86150
3 weeks ago
86 changed files with 0 additions and 7759 deletions
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*.jar |
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*.jar |
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*.class |
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*.log |
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# DataCollect 教学项目 — 最小可运行版本 |
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这是一个最小可用的 Java CLI 演示工程，目标：打印帮助信息以验证运行环境。 |
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构建： |
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```bash |
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mvn -q package |
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``` |
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运行（示例）： |
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```bash |
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java -jar target/datacollect-cli-0.1.0-jar-with-dependencies.jar --help |
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``` |
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项目结构（最小）： |
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- `src/main/java/com/example/datacollect/Main.java` — CLI 入口，打印帮助 |
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- `pom.xml` — Maven 构建配置，生成可执行 jar |
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<project xmlns="http://maven.apache.org/POM/4.0.0" |
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" |
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> |
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<modelVersion>4.0.0</modelVersion> |
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<groupId>com.example</groupId> |
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<artifactId>datacollect-cli</artifactId> |
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<version>0.1.0</version> |
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<properties> |
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<maven.compiler.source>11</maven.compiler.source> |
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<maven.compiler.target>11</maven.compiler.target> |
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</properties> |
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<build> |
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<plugins> |
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<plugin> |
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<groupId>org.apache.maven.plugins</groupId> |
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<artifactId>maven-compiler-plugin</artifactId> |
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<version>3.8.1</version> |
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</plugin> |
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<plugin> |
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<groupId>org.apache.maven.plugins</groupId> |
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<artifactId>maven-assembly-plugin</artifactId> |
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<version>3.3.0</version> |
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<configuration> |
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<archive> |
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<manifest> |
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<mainClass>com.example.datacollect.Main</mainClass> |
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</manifest> |
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</archive> |
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<descriptorRefs> |
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<descriptorRef>jar-with-dependencies</descriptorRef> |
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</descriptorRefs> |
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</configuration> |
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<executions> |
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<execution> |
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<id>make-assembly</id> |
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<phase>package</phase> |
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<goals> |
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<goal>single</goal> |
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</goals> |
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</execution> |
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</executions> |
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</plugin> |
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</plugins> |
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</build> |
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</project> |
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package com.example.datacollect; |
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import com.example.datacollect.controller.CrawlerController; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.ArrayList; |
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import java.util.List; |
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public class Main { |
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public static void main(String[] args) { |
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ConsoleView view = new ConsoleView(); |
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List<Article> articles = new ArrayList<>(); |
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CrawlerController controller = new CrawlerController(view, articles); |
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view.printSuccess("Welcome to CLI Crawler (w9_1)! Type help for commands."); |
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while (true) { |
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controller.handle(view.readLine()); |
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} |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.repository.ArticleRepository; |
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import com.example.datacollect.strategy.CrawlStrategy; |
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import com.example.datacollect.strategy.StrategyFactory; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.List; |
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public class AnalyzeCommand implements Command { |
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private final ConsoleView view; |
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public AnalyzeCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "analyze"; |
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} |
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@Override |
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public void execute(String[] args, ArticleRepository repository) { |
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if (args.length >= 2) { |
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String url = args[1]; |
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analyzeUrl(url); |
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} else { |
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analyzeRepository(repository); |
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} |
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} |
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private void analyzeUrl(String url) { |
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CrawlStrategy strategy = StrategyFactory.getStrategy(url); |
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if (strategy == null) { |
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view.printError("No strategy found for URL: " + url); |
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return; |
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} |
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view.printInfo("Analyzing URL: " + url); |
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view.printInfo("Using strategy: " + strategy.getClass().getSimpleName()); |
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List<Article> articles = strategy.crawl(url); |
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printAnalysis(articles); |
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view.printInfo("Note: Analysis results are NOT stored."); |
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} |
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private void analyzeRepository(ArticleRepository repository) { |
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List<Article> articles = repository.getAll(); |
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if (articles.isEmpty()) { |
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view.printInfo("No articles to analyze. Use 'analyze <url>' to analyze a URL without storing."); |
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return; |
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} |
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view.printInfo("Analyzing " + articles.size() + " articles from repository:"); |
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printAnalysis(articles); |
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} |
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private void printAnalysis(List<Article> articles) { |
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if (articles.isEmpty()) { |
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view.printInfo("No articles found."); |
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return; |
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} |
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int totalArticles = articles.size(); |
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int totalContentLength = 0; |
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int articlesWithAuthor = 0; |
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int articlesWithDate = 0; |
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for (Article article : articles) { |
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if (article.getContent() != null) { |
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totalContentLength += article.getContent().length(); |
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} |
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if (article.getAuthor() != null && !article.getAuthor().isEmpty()) { |
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articlesWithAuthor++; |
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} |
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if (article.getPublishDate() != null) { |
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articlesWithDate++; |
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} |
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} |
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double avgContentLength = totalArticles > 0 ? (double) totalContentLength / totalArticles : 0; |
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view.printInfo("=== Analysis Results ==="); |
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view.printInfo("Total articles: " + totalArticles); |
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view.printInfo("Total content length: " + totalContentLength); |
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view.printInfo("Average content length: " + String.format("%.2f", avgContentLength)); |
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view.printInfo("Articles with author: " + articlesWithAuthor); |
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view.printInfo("Articles with publish date: " + articlesWithDate); |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import java.util.List; |
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public interface Command { |
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String getName(); |
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void execute(String[] args, List<Article> articles); |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.List; |
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public class CrawlCommand implements Command { |
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private final ConsoleView view; |
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public CrawlCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "crawl"; |
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} |
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@Override |
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public void execute(String[] args, List<Article> articles) { |
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if (args.length < 2) { |
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view.printError("Usage: crawl <url>"); |
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return; |
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} |
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view.printInfo("Stub: would crawl " + args[1]); |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.List; |
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public class ExitCommand implements Command { |
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private final ConsoleView view; |
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public ExitCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "exit"; |
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} |
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@Override |
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public void execute(String[] args, List<Article> articles) { |
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view.printSuccess("Bye!"); |
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System.exit(0); |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.List; |
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public class HelpCommand implements Command { |
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private final ConsoleView view; |
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public HelpCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "help"; |
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} |
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@Override |
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public void execute(String[] args, List<Article> articles) { |
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view.printInfo("Commands:"); |
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view.printInfo(" crawl <url> - 爬取指定URL的文章"); |
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view.printInfo(" list - 列出已爬取的文章"); |
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view.printInfo(" history - 显示命令历史记录"); |
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view.printInfo(" help - 显示此帮助信息"); |
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view.printInfo(" exit - 退出程序"); |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.ArrayList; |
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import java.util.List; |
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public class HistoryCommand implements Command { |
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private static final List<String> commandHistory = new ArrayList<>(); |
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private final ConsoleView view; |
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public HistoryCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "history"; |
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} |
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@Override |
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public void execute(String[] args, List<Article> articles) { |
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if (commandHistory.isEmpty()) { |
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view.printInfo("No command history."); |
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return; |
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} |
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view.printInfo("Command History:"); |
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for (int i = 0; i < commandHistory.size(); i++) { |
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view.printInfo((i + 1) + ". " + commandHistory.get(i)); |
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} |
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} |
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public static void addCommand(String command) { |
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commandHistory.add(command); |
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} |
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public static List<String> getCommandHistory() { |
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return new ArrayList<>(commandHistory); |
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} |
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public static void clearHistory() { |
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commandHistory.clear(); |
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} |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.List; |
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public class ListCommand implements Command { |
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private final ConsoleView view; |
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public ListCommand(ConsoleView view) { |
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this.view = view; |
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} |
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@Override |
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public String getName() { |
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return "list"; |
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} |
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@Override |
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public void execute(String[] args, List<Article> articles) { |
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view.display(articles); |
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} |
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} |
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package com.example.datacollect.controller; |
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import com.example.datacollect.command.Command; |
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import com.example.datacollect.command.CrawlCommand; |
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import com.example.datacollect.command.ExitCommand; |
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import com.example.datacollect.command.HelpCommand; |
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import com.example.datacollect.command.HistoryCommand; |
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import com.example.datacollect.command.ListCommand; |
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import com.example.datacollect.model.Article; |
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import com.example.datacollect.view.ConsoleView; |
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import java.util.HashMap; |
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import java.util.List; |
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import java.util.Map; |
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public class CrawlerController { |
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private final Map<String, Command> commands = new HashMap<>(); |
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private final ConsoleView view; |
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private final List<Article> articles; |
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public CrawlerController(ConsoleView view, List<Article> articles) { |
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this.view = view; |
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this.articles = articles; |
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register(new HelpCommand(view)); |
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register(new ListCommand(view)); |
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register(new CrawlCommand(view)); |
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register(new ExitCommand(view)); |
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register(new HistoryCommand(view)); |
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} |
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private void register(Command command) { |
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commands.put(command.getName(), command); |
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} |
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public void handle(String input) { |
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String text = input == null ? "" : input.trim(); |
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if (text.isEmpty()) { |
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return; |
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} |
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// 记录命令历史
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HistoryCommand.addCommand(text); |
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String[] args = text.split("\\s+"); |
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String cmdName = args[0].toLowerCase(); |
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Command command = commands.get(cmdName); |
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if (command == null) { |
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view.printError("Unknown command: " + cmdName); |
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return; |
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} |
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command.execute(args, articles); |
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} |
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} |
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package com.example.datacollect.model; |
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import java.time.LocalDate; |
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public class Article { |
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private String title; |
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private String url; |
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private String content; |
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private String author; |
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private LocalDate publishDate; |
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public Article(String title, String url, String content) { |
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this.title = title; |
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this.url = url; |
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this.content = content; |
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} |
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public Article(String title, String url, String content, String author, LocalDate publishDate) { |
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this.title = title; |
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this.url = url; |
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this.content = content; |
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this.author = author; |
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this.publishDate = publishDate; |
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} |
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public String getTitle() { |
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return title; |
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} |
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public void setTitle(String title) { |
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this.title = title; |
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} |
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public String getUrl() { |
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return url; |
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} |
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public void setUrl(String url) { |
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this.url = url; |
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} |
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public String getContent() { |
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return content; |
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} |
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public void setContent(String content) { |
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this.content = content; |
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} |
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public String getAuthor() { |
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return author; |
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} |
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public void setAuthor(String author) { |
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this.author = author; |
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} |
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public LocalDate getPublishDate() { |
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return publishDate; |
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} |
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public void setPublishDate(LocalDate publishDate) { |
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this.publishDate = publishDate; |
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} |
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@Override |
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public String toString() { |
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return "Article{" |
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+ "title='" + title + '\'' |
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+ ", url='" + url + '\'' |
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+ ", author='" + author + '\'' |
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+ ", publishDate=" + publishDate |
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+ '}'; |
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} |
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} |
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@ -1,36 +0,0 @@ |
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package com.example.datacollect.repository; |
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import com.example.datacollect.model.Article; |
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import java.util.ArrayList; |
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import java.util.Collections; |
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import java.util.List; |
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public class ArticleRepository { |
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private final List<Article> articles = new ArrayList<>(); |
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public void add(Article article) { |
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if (article != null) { |
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articles.add(article); |
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} |
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||||
} |
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public void addAll(List<Article> articleList) { |
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if (articleList != null) { |
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||||
for (Article article : articleList) { |
|
||||
add(article); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
public List<Article> getAll() { |
|
||||
return Collections.unmodifiableList(articles); |
|
||||
} |
|
||||
|
|
||||
public void clear() { |
|
||||
articles.clear(); |
|
||||
} |
|
||||
|
|
||||
public int size() { |
|
||||
return articles.size(); |
|
||||
} |
|
||||
} |
|
||||
@ -1,20 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class BlogStrategy implements CrawlStrategy { |
|
||||
@Override |
|
||||
public boolean supports(String url) { |
|
||||
return url != null && (url.contains("blog") || url.contains("wordpress")); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> crawl(String url) { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
// 模拟博客爬取逻辑
|
|
||||
articles.add(new Article("博客文章标题", url, "博客文章内容", "作者", null)); |
|
||||
return articles; |
|
||||
} |
|
||||
} |
|
||||
@ -1,9 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface CrawlStrategy { |
|
||||
boolean supports(String url); |
|
||||
List<Article> crawl(String url); |
|
||||
} |
|
||||
@ -1,20 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class NewsStrategy implements CrawlStrategy { |
|
||||
@Override |
|
||||
public boolean supports(String url) { |
|
||||
return url != null && (url.contains("news") || url.contains("sina") || url.contains("163")); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> crawl(String url) { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
// 模拟新闻爬取逻辑
|
|
||||
articles.add(new Article("新闻标题", url, "新闻内容", "记者", null)); |
|
||||
return articles; |
|
||||
} |
|
||||
} |
|
||||
@ -1,26 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class StrategyFactory { |
|
||||
private static final List<CrawlStrategy> strategies = new ArrayList<>(); |
|
||||
|
|
||||
static { |
|
||||
strategies.add(new BlogStrategy()); |
|
||||
strategies.add(new NewsStrategy()); |
|
||||
} |
|
||||
|
|
||||
public static CrawlStrategy getStrategy(String url) { |
|
||||
for (CrawlStrategy strategy : strategies) { |
|
||||
if (strategy.supports(url)) { |
|
||||
return strategy; |
|
||||
} |
|
||||
} |
|
||||
return null; |
|
||||
} |
|
||||
|
|
||||
public static List<CrawlStrategy> getAllStrategies() { |
|
||||
return new ArrayList<>(strategies); |
|
||||
} |
|
||||
} |
|
||||
@ -1,42 +0,0 @@ |
|||||
package com.example.datacollect.view; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_RESET = "\u001B[0m"; |
|
||||
private static final String ANSI_GREEN = "\u001B[32m"; |
|
||||
private static final String ANSI_RED = "\u001B[31m"; |
|
||||
private static final String ANSI_BLUE = "\u001B[34m"; |
|
||||
|
|
||||
private final Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("> "); |
|
||||
return scanner.nextLine(); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
System.out.println(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
System.out.println(ANSI_BLUE + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("暂无文章，请先执行 crawl。"); |
|
||||
return; |
|
||||
} |
|
||||
for (int i = 0; i < articles.size(); i++) { |
|
||||
Article a = articles.get(i); |
|
||||
System.out.println((i + 1) + ". " + a.getTitle() + " | " + a.getUrl()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,758 +0,0 @@ |
|||||
--- |
|
||||
|
|
||||
# 教案：《高级程序设计》第9周——工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
| 项目 | 内容 | |
|
||||
|------|------| |
|
||||
| **课程名称** | 高级程序设计 | |
|
||||
| **周次** | 第9周 | |
|
||||
| **主题** | 工程架构——从"写代码"到"造系统" | |
|
||||
| **学时** | 2学时（90分钟） | |
|
||||
| **授课对象** | 具备Python基础、已完成Java面向对象特性学习的学生 | |
|
||||
| **教学环境** | JDK 17+、IntelliJ IDEA、Maven（模板） | |
|
||||
| **前情提要** | 本课程原计划使用JavaFX GUI，后根据教学反馈转向CLI + MVC + 爬虫工程化 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 教学调整说明：为什么选择CLI而不是GUI？ |
|
||||
|
|
||||
> **原计划**：JavaFX桌面应用 → **新计划**：CLI命令行应用 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **学生痛点** | "窗口点击"与后端能力无关 | 真正锻炼工程思维 | |
|
||||
| **AI辅助** | AI生成FXML，学生看不懂 | AI辅助重构架构 | |
|
||||
| **工程化** | 脱离真实后端开发场景 | 模拟真实服务器/大数据开发 | |
|
||||
| **核心转型** | "视觉装饰"优先 | "逻辑架构"优先 | |
|
||||
|
|
||||
**决策理由**： |
|
||||
1. **985学生需要的是工程思维**，不是拖控件 |
|
||||
2. **接口抽象**是弱项，CLI + MVC更能暴露这个问题 |
|
||||
3. **彩色终端**足够酷炫，且代码量可控 |
|
||||
|
|
||||
**更深层的教育价值**： |
|
||||
> 在GUI框架中，架构已被框架强制划定，学生只是"遵守规矩"；而CLI世界里没有任何框架告诉你模型在哪、视图在哪——**当外部约束消失，内部的工程纪律才真正建立**。这正是本节课要传递的核心精神。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 一、教学目标 |
|
||||
|
|
||||
| 目标维度 | 具体描述 | |
|
||||
|----------|----------| |
|
||||
| **知识掌握** | 理解MVC架构的职责划分及其演化脉络；掌握Maven项目结构与pom.xml基础；理解Command模式的路由原理。 | |
|
||||
| **工程实践** | 能搭建规范的Maven项目包结构；能实现基于Scanner的控制台交互；能用Command接口实现可扩展的命令路由；能识别架构中的"越权行为"。 | |
|
||||
| **思维转型** | 从"一个类写全部"转向"分层解耦"；从"修改现有代码"转向"新增类实现功能"；从"满足功能"转向"代码的工程洁癖"。 | |
|
||||
| **工具应用** | 利用AI辅助审查MVC职责越权；让AI扮演"架构审计师"检查分层是否清晰；理解AI生成代码中的架构缺陷。 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 二、教学重点与难点 |
|
||||
|
|
||||
| 项目 | 内容 | 突破方法 | |
|
||||
|------|------|----------| |
|
||||
| **重点** | MVC三层职责划分、CLI交互实现、Command接口解耦、代码中的工程细节（常量、输出归属） | 以"新增命令需要改什么"为切入点，展示Command模式的优势；通过现场"代码找茬"强化细节意识 | |
|
||||
| **难点** | Controller不写业务逻辑、Command接口的多态实现、共享数据模型的设计缺陷识别 | 现场演示：增加一个命令只需新建类，无需修改Controller；暴露`List<Article>`共享引用的问题并预告解决方案 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三、教学过程设计（90分钟） |
|
||||
|
|
||||
| 环节 | 时间 | 教学内容 | 师生活动 | AI协同点 | |
|
||||
|------|------|----------|----------|----------| |
|
||||
| **1. 痛点引入：从脚本到工程的鸿沟** | 10' | 展示"意大利面"式爬虫代码，演示改一处需要动全身 | **教师演示**：现场展示一段混乱代码，让学生找问题 | 用AI分析代码耦合度 | |
|
||||
| **2. CLI vs GUI：架构选择的思考** | 10' | 对比两种方案的优缺点，解释为什么CLI更适合培养工程思维 | **教师讲解**：用对比表格说明选择CLI的理由 | — | |
|
||||
| **3. MVC分层设计** | 20' | 讲解Model/View/Controller三层职责，用"餐厅类比"强化理解，随后批判类比局限性 | **教师讲解**：配合架构图讲解三层交互，引导学生寻找类比破绽 | 用AI生成MVC职责对照表 | |
|
||||
| **4. Command模式：可扩展的命令路由** | 15' | 引入Command接口，解释"一个命令就是一个类" | **类比**：Command像酒店的服务部门，Controller是前台 | 让AI解释Command模式的多态原理 | |
|
||||
| **5. Maven模板与环境** | 5' | 直接使用提供的Maven模板，讲解目录结构 | **教师演示**：解压模板 → IDEA打开 → 运行 | — | |
|
||||
| **6. 三层代码落地** | 20' | **Model**：Article实体<br>**View**：ConsoleView（ANSI常量）<br>**Command接口**+实现<br>**Controller**：Map路由 | **教师演示**：分步写出代码，刻意埋入1~2个"越权细节"让学生找茬 | 学生用AI做"架构审计" | |
|
||||
| **7. 架构反思与展望** | 5' | 指出当前`List<Article>`共享引用的问题，预告W10策略模式与仓库层 | **师生互动**：你发现这个设计有什么风险？ | 让AI分析共享可变状态的危害 | |
|
||||
| **8. 实践任务：空壳程序** | 5' | 搭建完整包结构，实现CLI循环 | 学生现场编码，教师巡视 | 完成后用AI检查包结构 | |
|
||||
| **9. 总结与过渡** | 5' | 本周实现了"骨架+命令可扩展"，下周填入"灵魂"——解析器，并解决数据安全问题 | 总结Command模式优势，预告策略模式 | — | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 四、核心教学内容脚本 |
|
||||
|
|
||||
### 4.1 痛点引入：从脚本到工程的鸿沟（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "同学们，前8周我们学的是Java语法，从变量到类，从继承到接口。但有一个问题：代码写完之后，怎么组织？" |
|
||||
> |
|
||||
> "来看这段代码——这是某个同学写的'爬虫'，他一个人完成了一个'完整'的项目。" |
|
||||
|
|
||||
**展示"脚本式"代码**： |
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
|
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问引导**： |
|
||||
1. "如果我想把标题保存到文件，要改哪里？" |
|
||||
2. "如果我想支持另一个网站，它的HTML结构不一样，要怎么办？" |
|
||||
3. "如果我想让输出变成彩色，要改哪里？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "看到了吗？才60行代码，已经'牵一发而动全身'了。这就是一个'脚本'的宿命——功能全混在一起，改一个小需求，整个文件都要翻。" |
|
||||
> |
|
||||
> "这周我们要解决：**怎么让代码'改起来不疼'？**" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.2 CLI vs GUI：架构选择的思考（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "既然要写一个'完整'的爬虫应用，我们有两个选择：图形界面（GUI）或命令行界面（CLI）。为什么我推荐CLI而不是GUI？" |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **代码量** | FXML + Controller + CSS，大量模板代码 | 纯Java，代码量可控 | |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **后端能力** | 几乎无关 | 模拟真实服务器开发 | |
|
||||
| **可测试性** | 难（需要UI测试框架） | 易（直接测试Command类） | |
|
||||
| **工程思维** | 弱（关注视觉） | 强（关注逻辑） | |
|
||||
|
|
||||
**核心观点**： |
|
||||
> **CLI更需要MVC！** GUI有现成的事件系统（点击按钮→触发事件），而CLI只有字符流。**没有架构，分分钟写成脚本**。MVC在CLI里是"刚需"，不是"装饰"。 |
|
||||
> |
|
||||
> **更深一层**：在GUI里，框架已经硬塞给你一套架构，你只是在填空；但在CLI里，所有结构都必须由你亲手搭建。**当外部约束消失，内部的工程纪律才真正开始建立**——这才是本节课的真正目的。 |
|
||||
|
|
||||
**CLI也能很酷**： |
|
||||
- ANSI彩色输出（红/绿/黄/蓝） |
|
||||
- 表格展示数据 |
|
||||
- 进度条动画 |
|
||||
- 模拟真实大数据开发场景 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.3 MVC分层设计（20分钟） |
|
||||
|
|
||||
#### 4.3.1 MVC的起源与演进 |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "MVC不是新东西，它是1970年代为桌面应用设计的架构思想。但它的核心——'职责分离'——在任何软件里都适用。" |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
#### 4.3.2 从GUI到CLI的映射 |
|
||||
|
|
||||
| GUI组件 | CLI对应 | 说明 | |
|
||||
|--------|--------|------| |
|
||||
| 窗口/按钮 | 命令行输入 | **View = 用户交互** | |
|
||||
| 数据模型 | Article实体类 | **Model = 数据结构** | |
|
||||
| 事件监听 | Command路由 | **Controller = 调度** | |
|
||||
|
|
||||
#### 4.3.3 MVC三层职责 |
|
||||
|
|
||||
**架构图示**： |
|
||||
|
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
│ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ - 接收命令（crawl, help, exit） │ |
|
||||
│ - 分发给对应的Command │ |
|
||||
│ 【口诀】：Controller不管"怎么做"， │ |
|
||||
│ 只管"派给谁" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
│ │ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ - 数据实体 │ │ - 输入解析 │ |
|
||||
│ - 业务逻辑 │ │ - 输出格式化 │ |
|
||||
│ 【口诀】： │ │ 【口诀】： │ |
|
||||
│ Model管"数据" │ │ View管"呈现" │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
**三层职责详解** |
|
||||
|
|
||||
| 层级 | 职责 | 典型代码 | 禁止做什么 | |
|
||||
|------|------|----------|------------| |
|
||||
| **Model** | 数据结构 + 业务逻辑 | `class Article { String title; String content; }` | 不能有`System.out.println`，不能有`Scanner` | |
|
||||
| **View** | 接收用户输入 + 格式化输出 | `class ConsoleView { String readInput(); void print(String); }` | 不能写爬虫逻辑，只做"传声筒" | |
|
||||
| **Controller** | 协调调度 | `class CrawlerController { void handle(String cmd) { ... } }` | 不能直接写业务细节，委托给Command | |
|
||||
|
|
||||
#### 4.3.4 类比强化："餐厅类比" |
|
||||
|
|
||||
> "把MVC想象成一家餐厅： |
|
||||
> - **Model是后厨**：只管做菜（数据加工），不管谁来吃、怎么端 |
|
||||
> - **View是服务员**：只管端菜和收钱（输入输出），不管菜怎么做 |
|
||||
> - **Controller是前台**：只管把顾客的点单传给后厨，把做好的菜端给顾客 |
|
||||
> |
|
||||
> 如果后厨开始管'谁来吃饭'，这餐厅就乱了。" |
|
||||
|
|
||||
#### 4.3.5 对"餐厅类比"的批判性思考（关键！） |
|
||||
|
|
||||
**教师导引**： |
|
||||
> "刚才的类比好理解吗？很好。但任何一个类比都有它的边界，如果把它当成真理，就会出问题。现在我们来给这个类比'找茬'。" |
|
||||
|
|
||||
**提问学生**： |
|
||||
1. "后厨真的完全不知道客人是谁吗？如果客人有忌口（比如不吃香菜），这个信息需不需要传到后厨？" |
|
||||
2. "服务员只是端菜吗？在真实餐厅里，服务员经常向后厨反馈'客人觉得今天的菜咸了'，这属于View→Model的反向影响吗？" |
|
||||
3. "在这个类比里，我们把前台（Controller）和后厨（Model）的关系说成单向的。但实际上，后厨做完了菜，需要通知前台'菜好了'，这不就是**观察者模式**吗？" |
|
||||
|
|
||||
**点明本质**： |
|
||||
> "实际MVC的数据流向常常是**双向**的：Controller调用Model的方法改变数据，Model变化后又通知View更新显示。只不过在本次CLI项目中，我们暂时使用'请求-响应'的单向简化模型——用户输入命令，系统处理，然后立即输出结果。这个简化版够用，但你要知道完整的MVC是更动态的。随着系统复杂，Model层需要一个专门的'仓库类'来管理数据，并通知视图刷新——这正是W10我们将要深入的内容。" |
|
||||
|
|
||||
#### 4.3.6 MVC的数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，目前暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.4 Command模式：可扩展的命令路由（15分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在引入一个设计模式——Command（命令）模式。它的核心思想是：**一个命令就是一个类**。" |
|
||||
|
|
||||
#### 4.4.1 为什么需要Command模式？ |
|
||||
|
|
||||
**演示：增加一个命令的代价（switch-case版）** |
|
||||
```java |
|
||||
// 现状代码 |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果我想增加10个命令，这个类要改多少次？" |
|
||||
- "如果我不小心删了一个case，整个程序还能跑吗？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "每加一个功能，就要在这个类里戳一个洞。**这就是'肥控制器'陷阱**——所有的逻辑都堆在Controller里，它变成了新的'意大利面'。" |
|
||||
|
|
||||
#### 4.4.2 Command模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| **Command接口** | 抽象的"订单" | `Command` 接口 | |
|
||||
| **ConcreteCommand** | 具体的订单 | `HelpCommand`、`CrawlCommand` | |
|
||||
| **Invoker** | 接单的前台 | `CrawlerController` | |
|
||||
| **Receiver** | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
#### 4.4.3 Command接口定义 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/command/Command.java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); // 命令名，如 "crawl" |
|
||||
void execute(String[] args, List<Article> articles); // 执行逻辑 |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.4.4 Controller的变革（从switch到Map） |
|
||||
|
|
||||
```java |
|
||||
// 修改后的Controller |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands; // 用Map存命令 |
|
||||
private ConsoleView view; // 持有View以输出错误 |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.commands = new HashMap<>(); |
|
||||
// 增加命令无需改Controller代码，只需在这里注册 |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmd = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command command = commands.get(cmd); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmd); // 通过View输出，而非直接System.out |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 执行命令，传入参数和文章列表 |
|
||||
command.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | execute()的多态调用 | |
|
||||
| 可测试性 | 难 | 每个Command可单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
**类比强化**： |
|
||||
> "Command模式就像**酒店的客房服务**：每个服务（清理、送餐、按摩）都是一个独立的部门。前台（Controller）只负责接电话，然后把请求'派发'给对应的部门。部门自己知道怎么干活，不需要前台教。" |
|
||||
> |
|
||||
> "如果想新增一个服务，前台只需要'登记'一下，不需要把现有部门重新装修。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.5 Maven模板与环境（5分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "这周我们不发愁pom.xml配置。我已经把 Maven 模板准备好了，你们只需要解压、打开、运行。" |
|
||||
|
|
||||
**模板使用流程**： |
|
||||
``` |
|
||||
1. 解压 [my-crawler-template.zip] |
|
||||
2. 用 IDEA 打开文件夹 |
|
||||
3. 右键 pom.xml → Maven → Reload Project |
|
||||
4. 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
**标准目录结构**： |
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/ |
|
||||
│ └── Article.java |
|
||||
├── view/ |
|
||||
│ └── ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java (接口) |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/ |
|
||||
└── CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.6 代码落地（20分钟） |
|
||||
|
|
||||
#### 4.6.1 Model层：Article实体 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/model/Article.java |
|
||||
package com.crawler.model; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { return title; } |
|
||||
public void setTitle(String title) { this.title = title; } |
|
||||
public String getUrl() { return url; } |
|
||||
public void setUrl(String url) { this.url = url; } |
|
||||
public String getContent() { return content; } |
|
||||
public void setContent(String content) { this.content = content; } |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{title='" + title + "', url='" + url + "'}"; |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.2 View层：ANSI常量集中管理（工程细节！） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/view/ConsoleView.java |
|
||||
package com.crawler.view; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
// ANSI颜色常量——集中管理，避免散落各处 |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
private static final String ANSI_CYAN = "\033[36m"; |
|
||||
private static final String ANSI_RESET = "\033[0m"; |
|
||||
|
|
||||
private Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("crawler> "); |
|
||||
return scanner.nextLine().trim(); |
|
||||
} |
|
||||
|
|
||||
public void print(String msg) { |
|
||||
System.out.println(msg); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
print(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
print(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
print(ANSI_CYAN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
// 展示文章列表 |
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("No articles yet. Use 'crawl <url>' first."); |
|
||||
return; |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
print("| Title | URL |"); |
|
||||
print("+----------+--------------------------------+"); |
|
||||
for (Article a : articles) { |
|
||||
String title = a.getTitle(); |
|
||||
if (title.length() > 10) title = title.substring(0, 10) + ".."; |
|
||||
String url = a.getUrl(); |
|
||||
if (url.length() > 30) url = url.substring(0, 27) + "..."; |
|
||||
print("| " + String.format("%-10s", title) + " | " + url + " |"); |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
printInfo("Total: " + articles.size() + " articles"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**教师提示**： |
|
||||
> "注意：所有ANSI转义码都被定义为`private static final`常量。如果把`\033[32m`散落在项目各处，一旦想调整颜色，就得满世界去改——这正是我们之前痛批的'意大利面'。**这就是工程细节**。" |
|
||||
|
|
||||
#### 4.6.3 Command接口与四个实现（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// Command.java |
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
|
|
||||
// HelpCommand.java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ListCommand.java |
|
||||
public class ListCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ListCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "list"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// CrawlCommand.java (存根) |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ExitCommand.java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); // 全部输出都通过View，绝不让System.out直接出现在这里 |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**故意埋设的"找茬点"**： |
|
||||
> "我在刚才的代码里有没有隐藏违反MVC原则的地方？`CrawlCommand`的存根里，`view.printInfo("Stub: Would crawl " + args[1]);` —— 这个字符串拼接算是"业务逻辑"吗？留给大家用AI架构审计时讨论。 |
|
||||
|
|
||||
#### 4.6.4 Controller：Map路由（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/controller/CrawlerController.java |
|
||||
package com.crawler.controller; |
|
||||
|
|
||||
import com.crawler.command.*; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
private ConsoleView view; // 持有View |
|
||||
private List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmdName = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command cmd = commands.get(cmdName); |
|
||||
if (cmd == null) { |
|
||||
view.printError("Unknown command: " + cmdName); // 错误信息也走View！ |
|
||||
return; |
|
||||
} |
|
||||
cmd.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.5 main方法：组装 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/App.java |
|
||||
package com.crawler; |
|
||||
|
|
||||
import com.crawler.controller.CrawlerController; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class App { |
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
view.printInfo("Type 'help' for commands."); |
|
||||
|
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.6 架构反思与展望：共享List<Article>的隐患（关键！） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在这个架构已经可用了。但请大家审视一下：我们所有的Command都直接拿到了`List<Article>`的引用。换句话说，任何一个命令都可以随意增、删、改这个列表。" |
|
||||
> |
|
||||
> "这就好像一家酒店，所有服务员、厨师、清洁工都能随意进出保险箱——**数据结构完全裸奔了**。" |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果CrawlCommand不小心写错了代码，把一个null塞进articles，HelpCommand会不会受影响？" |
|
||||
- "如果未来我们要在添加文章时也写入日志文件，现在的设计能优雅实现吗？还是得在所有Command里分别加日志代码？" |
|
||||
|
|
||||
**预告解决方案**： |
|
||||
> "下周，我们将引入**策略模式**和一个真正的**Model仓库层（ArticleRepository）**。这个仓库会把`List`封装起来，对外只提供`add()`、`getAll()`等安全接口。任何命令想修改数据，都必须通过仓库。这就是从'数据结构'到'模型层'的进化——我们W9先搭骨架，W10给它装上盔甲。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.7 实践任务（5分钟） |
|
||||
|
|
||||
**任务要求**： |
|
||||
1. 使用Maven模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现4个Command：help/list/crawl/exit |
|
||||
4. `list`命令能展示已抓取的文章 |
|
||||
5. 运行并测试循环 |
|
||||
6. **代码找茬（额外加分）**：找出你自己代码中是否存在`System.out`直接调用、硬编码ANSI字符串等"越权行为" |
|
||||
|
|
||||
**验收标准**： |
|
||||
- [x] Maven编译通过 |
|
||||
- [x] Command接口和4个实现分离在不同文件 |
|
||||
- [x] Controller里没有switch-case |
|
||||
- [x] 新增命令只需新建类，不改Controller |
|
||||
- [x] list命令能正确显示空列表 |
|
||||
- [x] 所有输出均通过ConsoleView完成，无直接System.out.println（main除外） |
|
||||
- [x] ANSI颜色码集中定义为View常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 五、课后作业 |
|
||||
|
|
||||
### 5.1 必做任务 |
|
||||
|
|
||||
1. **完善Article**：增加`author`、`publishDate`字段 |
|
||||
2. **★ HistoryCommand（强制作业）**： |
|
||||
- 实现`history`命令，记录用户输入过的所有命令 |
|
||||
- 使用`List<String>`存储历史（复习W8集合） |
|
||||
- 示例输出： |
|
||||
``` |
|
||||
crawler> history |
|
||||
1. help |
|
||||
2. list |
|
||||
3. crawl https://example.com |
|
||||
``` |
|
||||
3. **AI架构审计**：将类名和方法名发给AI，指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？Model层是否包含输入输出代码？View层是否越权写了业务逻辑？有没有地方直接使用了System.out或硬编码ANSI码？" |
|
||||
|
|
||||
### 5.2 选做任务 |
|
||||
|
|
||||
1. **命令别名**：给`crawl`增加别名`c`，`help`增加别名`h` |
|
||||
2. **URL验证**：检查URL格式是否以http://或https://开头 |
|
||||
3. **暗色主题**：实现不同的配色方案（利用View中的ANSI常量，只需修改一处即可） |
|
||||
4. **思考并回答**：分析`List<Article>`共享引用的潜在风险，写一段200字的小结 |
|
||||
|
|
||||
### 5.3 思考题 |
|
||||
|
|
||||
1. **Command vs switch-case**：增加10个命令，哪种方式代码改动量更小？ |
|
||||
2. **如果不用Command接口，直接用Map存命令类行不行？** 接口的意义是什么？ |
|
||||
3. **Controller里的`commands.put()`能否减少？** 提示：思考"注册机制" |
|
||||
4. **为什么ExitCommand里的`view.printSuccess("Bye!")`比直接`System.out.println`更"MVC"？** 提示：回忆View的职责 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 六、AI协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**学生执行步骤**： |
|
||||
1. 列出项目中所有类名（不含方法实现） |
|
||||
2. 将类名列表发给AI |
|
||||
3. 输入指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否清晰。Model层是否包含了不应该有的代码（Scanner/System.out）？View层是否越权写了业务逻辑？请指出任何一处直接使用System.out.println的地方，并建议如何改正。" |
|
||||
|
|
||||
**预期AI输出**： |
|
||||
- 指出哪一层有越权行为 |
|
||||
- 建议如何整改 |
|
||||
- 评价整体架构健康度 |
|
||||
|
|
||||
### 进阶AI探究（选做） |
|
||||
|
|
||||
> "假设我的Command接口中execute方法接收了一个`List<Article>`参数，请分析这种设计在工程上有什么隐患，并给出重构建议。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 七、教学反思与调整记录 |
|
||||
|
|
||||
| 日期 | 事项 | 调整内容 | |
|
||||
|------|------|----------| |
|
||||
| 2026-04-28 | 首次编写 | 基于CLI+MVC重构 | |
|
||||
| 2026-04-30 | 教授反馈 | 引入Command模式、提供Maven模板、升级AI协同比 | |
|
||||
| 2026-04-30 | 逻辑重排 | 按"问题→选择→架构→模式"顺序重写 | |
|
||||
| 2026-05-01 | v2 vs V3合并 | 融合深度改进：增加教育哲学、批判性思考、ANSI常量、共享List隐患、故意埋坑 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 附录1：Maven模板说明 |
|
||||
|
|
||||
> 老师提供`my-crawler-template.zip`压缩包，包含： |
|
||||
> - pom.xml（含Jsoup依赖） |
|
||||
> - 空的src/main/java结构 |
|
||||
> - .gitignore |
|
||||
|
|
||||
## 附录2：常见问题速查 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA不识别pom.xml | 右键 pom.xml → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → Editor → File Encodings → UTF-8 | |
|
||||
| 包名大小写 | 包名全小写，类名首字母大写 | |
|
||||
| Command找不到 | 检查是否 implements Command，是否 @Override getName() | |
|
||||
| 命令不生效 | 检查 commands.put() 是否注册了该命令 | |
|
||||
| 输出颜色乱码 | IDEA控制台需支持ANSI，Windows下建议使用Windows Terminal或调整设置 | |
|
||||
| 我的System.out为什么被老师说越权 | View层才是与用户交互的唯一出口，所有输出都应通过View，这样将来改成GUI或日志时只需改View | |
|
||||
|
|
||||
## 附录3：教学逻辑说明 |
|
||||
|
|
||||
| 顺序 | 内容 | 设计理由 | |
|
||||
|------|------|----------| |
|
||||
| 1 | 痛点引入 | 从问题出发，让学生感受"为什么需要架构" | |
|
||||
| 2 | CLI vs GUI | 解释技术选型，建立"工程思维 > 视觉装饰"的认知 | |
|
||||
| 3 | MVC分层 | 核心架构概念，理解职责分离，通过类比及批判加深理解 | |
|
||||
| 4 | Command模式 | 具体实现方式，解决"肥控制器"问题 | |
|
||||
| 5 | Maven | 工具链支持 | |
|
||||
| 6 | 代码落地 | 实践验证，刻意植入细节规范，训练工程洁癖 | |
|
||||
| 7 | 架构反思 | 暴露共享可变状态隐患，为W10策略模式+仓库层做铺垫 | |
|
||||
| 8 | 实践任务 | 现场编码验证 | |
|
||||
| 9 | 总结 | 强化认知，预告下周 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 版本说明 |
|
||||
|
|
||||
- **v1**：首次编写，CLI+MVC基础框架 |
|
||||
- **v2**：按"问题→选择→架构→模式"逻辑重排 |
|
||||
- **v3 (本版)**：融合v2结构 + V3深度改进，包含： |
|
||||
- 更深的CLI教育哲学 |
|
||||
- 餐厅类比批判性思考 |
|
||||
- ANSI常量集中管理工程细节 |
|
||||
- 全部输出走View |
|
||||
- 共享List架构隐患反思 |
|
||||
- 故意埋坑让学生找茬 |
|
||||
- W10铺垫（策略模式+仓库层） |
|
||||
@ -1,5 +0,0 @@ |
|||||
#Generated by Maven |
|
||||
#Thu Apr 30 11:50:54 CST 2026 |
|
||||
artifactId=datacollect-cli |
|
||||
groupId=com.example |
|
||||
version=0.1.0 |
|
||||
@ -1,530 +0,0 @@ |
|||||
## 高级程序设计 · 第9周 |
|
||||
|
|
||||
#### 工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
##### CLI + MVC + Command模式实战 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 📌 本周导航 |
|
||||
|
|
||||
- 痛点引入：脚本的宿命 |
|
||||
- CLI vs GUI：为什么选命令行？ |
|
||||
- MVC分层：职责分离的艺术 |
|
||||
- Command模式：可扩展的路由 |
|
||||
- Maven模板：工程化第一步 |
|
||||
- 代码落地：从接口到实现 |
|
||||
- 架构反思：共享数据的隐患 |
|
||||
- 实践任务 + 课后作业 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 1️⃣ 痛点引入：从脚本到工程的鸿沟 |
|
||||
|
|
||||
#### 这是一段“意大利面”爬虫 |
|
||||
|
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 脚本的三大痛点 |
|
||||
|
|
||||
| 需求 | 需要改哪里？ | |
|
||||
|------|--------------| |
|
||||
| 保存标题到文件 | 改 main 内部逻辑 | |
|
||||
| 支持不同网站结构 | 全部重写解析代码 | |
|
||||
| 彩色输出 | 一个一个改 print | |
|
||||
|
|
||||
> 😫 **牵一发而动全身 → 改起来疼** |
|
||||
|
|
||||
### 本周目标：**让代码“改起来不疼”** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 2️⃣ CLI vs GUI：架构选择的思考 |
|
||||
|
|
||||
### 图形界面 vs 命令行 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| 学习重心 | 布局、控件、事件 | **架构、分层、路由** | |
|
||||
| 后端能力 | 弱 | 模拟真实服务器 | |
|
||||
| 工程思维 | 弱（关注视觉） | **强（关注逻辑）** | |
|
||||
| 可测试性 | 难 | 易 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 核心观点 |
|
||||
|
|
||||
> **CLI 更需要 MVC！** |
|
||||
|
|
||||
- GUI 有现成事件系统，框架强塞给你一套架构 |
|
||||
- CLI 只有字符流 → **没有架构，分分钟写成脚本** |
|
||||
|
|
||||
> 🎯 **当外部约束消失，内部的工程纪律才真正开始建立** |
|
||||
|
|
||||
### CLI 也能很酷 |
|
||||
|
|
||||
- ANSI 彩色输出 |
|
||||
- 表格展示数据 |
|
||||
- 模拟大数据/后端开发 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 3️⃣ MVC 分层设计 |
|
||||
|
|
||||
### MVC 的起源与演进 |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
**核心不变：职责分离** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 三层职责 |
|
||||
|
|
||||
![[mvc.png]] |
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ 只管"派给谁"，不管"怎么做" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ 管"数据" │ │ 管"呈现" │ |
|
||||
│ + 业务逻辑 │ │ + 输入输出 │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三层“禁止做什么” |
|
||||
|
|
||||
| 层级 | 禁止行为 | |
|
||||
| -------------- | -------------------------------------- | |
|
||||
| **Model** | 不能有 `System.out.println`，不能有 `Scanner` | |
|
||||
| **View** | 不能写爬虫逻辑，只做“传声筒” | |
|
||||
| **Controller** | 不能直接写业务细节，委托给 Command | |
|
||||
|
|
||||
> 🔴 **越权就是架构腐败的开始** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🍽️ 餐厅类比（帮助理解） |
|
||||
|
|
||||
- **Model = 后厨**：只管做菜，不管谁来吃、怎么端 |
|
||||
- **View = 服务员**：只管端菜和收钱，不管菜怎么做 |
|
||||
- **Controller = 前台**：接单 → 派给后厨 → 叫服务员上菜 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤔 对类比的批判性思考（关键！） |
|
||||
|
|
||||
> 任何类比都有边界，不要当成真理 |
|
||||
|
|
||||
| 场景 | 暴露的问题 | |
|
||||
|------|------------| |
|
||||
| 客人有忌口（不吃香菜） | 信息需要传到后厨 → Model 可能需要知道 meta 信息 | |
|
||||
| 服务员反馈“今天的菜咸了” | View → Model 反向影响 | |
|
||||
| 后厨做完菜通知前台 | **观察者模式**，数据流可能是双向的 | |
|
||||
|
|
||||
**本课程简化模型**：请求-响应，单向流 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 4️⃣ Command 模式：可扩展的命令路由 |
|
||||
|
|
||||
### 为什么需要 Command 模式？ |
|
||||
|
|
||||
```java |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 每加一个功能，就要在这个类里戳一个洞 → **肥控制器陷阱** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| Command接口 | 抽象的“订单” | `Command` | |
|
||||
| ConcreteCommand | 具体的订单 | `HelpCommand` | |
|
||||
| Invoker | 接单的前台 | `CrawlerController` | |
|
||||
| Receiver | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 接口定义 |
|
||||
|
|
||||
```java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller 的变革：从 switch 到 Map |
|
||||
|
|
||||
```java |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
// 解析命令 → 从 Map 取 Command → 调用 execute |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> **增加新命令：只需新建类，Controller 零改动！** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 对比：switch-case vs Command |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改 Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | `execute()` 多态 | |
|
||||
| 可测试性 | 难 | 每个 Command 单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
> 🏨 **类比：酒店客房服务，前台只负责派单** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 5️⃣ Maven 模板与环境（5分钟） |
|
||||
|
|
||||
### 直接使用模板，不折腾配置 |
|
||||
|
|
||||
``` |
|
||||
my-crawler-template.zip |
|
||||
↓ 解压 + IDEA打开 |
|
||||
↓ 右键 pom.xml → Maven → Reload Project |
|
||||
↓ 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
### 标准目录结构 |
|
||||
|
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/Article.java |
|
||||
├── view/ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 6️⃣ 代码落地（分步实现） |
|
||||
|
|
||||
### Model：Article 实体 |
|
||||
|
|
||||
```java |
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
// 构造器、getter/setter、toString |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 📦 只存放数据，没有任何输入输出代码 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## View：ConsoleView（ANSI常量集中管理） |
|
||||
|
|
||||
```java |
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
// ... 其他常量 |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
public void printError(String msg) { ... } |
|
||||
public void display(List<Article> articles) { ... } |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✨ **所有颜色码集中定义 → 改主题只需改一处** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 实现示例（HelpCommand） |
|
||||
|
|
||||
```java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ⚠️ 全部输出通过 `view`，绝不让 `System.out` 直接出现在这里 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## CrawlCommand（存根，下周填坑） |
|
||||
|
|
||||
```java |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔍 **找茬点**：这里拼接字符串算是“业务逻辑”吗？留给大家用 AI 审计。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## ExitCommand |
|
||||
|
|
||||
```java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✅ 所有输出都通过 View → 将来改 GUI 只需换 View 实现 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller + main 组装 |
|
||||
|
|
||||
```java |
|
||||
// Controller 中持有 Map<String,Command> |
|
||||
// App.java 中： |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔁 完成交互循环 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 7️⃣ 架构反思：共享 List<Article> 的隐患 |
|
||||
|
|
||||
### 当前问题 |
|
||||
|
|
||||
- 所有 Command 都直接拿到 `List<Article>` 引用 |
|
||||
- 任何一个命令都可以随意增、删、改列表 |
|
||||
- 数据完全“裸奔” |
|
||||
|
|
||||
> 🚨 就像酒店所有员工都能进保险箱 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 提问 |
|
||||
|
|
||||
- 如果 `CrawlCommand` 不小心把 `null` 塞进列表，`ListCommand` 会怎样？ |
|
||||
- 如果我们要在添加文章时写日志，现在的设计能优雅实现吗？ |
|
||||
|
|
||||
### 预告解决方案（W10） |
|
||||
|
|
||||
- **策略模式** + **仓库层（ArticleRepository）** |
|
||||
- 封装 `List`，对外只暴露 `add()`、`getAll()` 等安全接口 |
|
||||
|
|
||||
> W9 搭骨架，W10 装上盔甲 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 8️⃣ 实践任务（现场5分钟） |
|
||||
|
|
||||
### 必做项 |
|
||||
|
|
||||
1. 使用 Maven 模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现 4 个 Command：help / list / crawl / exit |
|
||||
4. `list` 能展示已抓取的文章（目前存根即可） |
|
||||
5. 运行并测试循环 |
|
||||
|
|
||||
### 额外加分：代码找茬 |
|
||||
|
|
||||
- 检查是否仍有 `System.out` 直接调用 |
|
||||
- 检查 ANSI 码是否硬编码在多个地方 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 验收标准 |
|
||||
|
|
||||
- [x] Maven 编译通过 |
|
||||
- [x] Command 接口和 4 个实现在不同文件 |
|
||||
- [x] Controller 里没有 switch-case |
|
||||
- [x] 新增命令只需新建类，不改 Controller |
|
||||
- [x] list 能正确显示空列表 |
|
||||
- [x] 所有输出均通过 `ConsoleView` |
|
||||
- [x] ANSI 颜色码集中定义为常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 9️⃣ 课后作业 |
|
||||
|
|
||||
### 必做 |
|
||||
|
|
||||
1. **完善 Article**：增加 `author`、`publishDate` 字段 |
|
||||
2. **★ HistoryCommand**：记录用户输入过的所有命令（用 `List<String>`） |
|
||||
3. **AI 架构审计**：将类名发给 AI，指令： |
|
||||
> “作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？” |
|
||||
|
|
||||
### 选做 |
|
||||
|
|
||||
- 命令别名（c 代替 crawl） |
|
||||
- URL 格式验证 |
|
||||
- 暗色主题（修改一处常量） |
|
||||
- 思考题：分析 `List<Article>` 共享引用的风险（200字小结） |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤖 AI 协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**步骤**： |
|
||||
1. 列出所有类名（不含方法实现） |
|
||||
2. 发给 AI |
|
||||
3. 指令：“检查 MVC 分层是否清晰，是否有越权行为” |
|
||||
|
|
||||
### 进阶探究（选做） |
|
||||
|
|
||||
> “假设我的 Command 接口中 execute 方法接收了一个 `List<Article>` 参数，请分析这种设计在工程上有什么隐患，并给出重构建议。” |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 📚 总结与过渡 |
|
||||
|
|
||||
### 本周成果 |
|
||||
|
|
||||
- ✅ 工程化包结构 |
|
||||
- ✅ MVC 分层清晰 |
|
||||
- ✅ Command 模式实现可扩展路由 |
|
||||
- ✅ 所有输出走 View，常量集中管理 |
|
||||
|
|
||||
### 下周预告 |
|
||||
|
|
||||
- **策略模式**：封装爬取算法 |
|
||||
- **仓库层（Repository）**：武装 `List<Article>`，解决共享隐患 |
|
||||
|
|
||||
> 🚀 从“写代码”到“造系统”，踏出坚实第一步！ |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Q&A |
|
||||
|
|
||||
### 常见问题 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA 不识别 pom.xml | 右键 → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → File Encodings → UTF-8 | |
|
||||
| 输出颜色乱码 | Windows 建议使用 Windows Terminal | |
|
||||
| 我的 System.out 被批评 | View 才是唯一输出出口 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 谢谢！ |
|
||||
|
|
||||
### 课件已上传，模板在课程群 |
|
||||
|
|
||||
**保持工程洁癖，下周见！** |
|
||||
@ -1,4 +0,0 @@ |
|||||
*.jar |
|
||||
*.jar |
|
||||
*.class |
|
||||
*.log |
|
||||
@ -1,17 +0,0 @@ |
|||||
# DataCollect 教学项目 — 最小可运行版本 |
|
||||
|
|
||||
这是一个最小可用的 Java CLI 演示工程，目标：打印帮助信息以验证运行环境。 |
|
||||
|
|
||||
构建： |
|
||||
```bash |
|
||||
mvn -q package |
|
||||
``` |
|
||||
|
|
||||
运行（示例）： |
|
||||
```bash |
|
||||
java -jar target/datacollect-cli-0.1.0-jar-with-dependencies.jar --help |
|
||||
``` |
|
||||
|
|
||||
项目结构（最小）： |
|
||||
- `src/main/java/com/example/datacollect/Main.java` — CLI 入口，打印帮助 |
|
||||
- `pom.xml` — Maven 构建配置，生成可执行 jar |
|
||||
@ -1,59 +0,0 @@ |
|||||
<project xmlns="http://maven.apache.org/POM/4.0.0" |
|
||||
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" |
|
||||
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> |
|
||||
<modelVersion>4.0.0</modelVersion> |
|
||||
<groupId>com.example</groupId> |
|
||||
<artifactId>datacollect-cli</artifactId> |
|
||||
<version>0.1.0</version> |
|
||||
<properties> |
|
||||
<maven.compiler.source>11</maven.compiler.source> |
|
||||
<maven.compiler.target>11</maven.compiler.target> |
|
||||
</properties> |
|
||||
|
|
||||
<dependencies> |
|
||||
<dependency> |
|
||||
<groupId>org.jsoup</groupId> |
|
||||
<artifactId>jsoup</artifactId> |
|
||||
<version>1.17.2</version> |
|
||||
</dependency> |
|
||||
<dependency> |
|
||||
<groupId>ch.qos.logback</groupId> |
|
||||
<artifactId>logback-classic</artifactId> |
|
||||
<version>1.4.14</version> |
|
||||
</dependency> |
|
||||
</dependencies> |
|
||||
|
|
||||
<build> |
|
||||
<plugins> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-compiler-plugin</artifactId> |
|
||||
<version>3.8.1</version> |
|
||||
</plugin> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-assembly-plugin</artifactId> |
|
||||
<version>3.3.0</version> |
|
||||
<configuration> |
|
||||
<archive> |
|
||||
<manifest> |
|
||||
<mainClass>com.example.datacollect.Main</mainClass> |
|
||||
</manifest> |
|
||||
</archive> |
|
||||
<descriptorRefs> |
|
||||
<descriptorRef>jar-with-dependencies</descriptorRef> |
|
||||
</descriptorRefs> |
|
||||
</configuration> |
|
||||
<executions> |
|
||||
<execution> |
|
||||
<id>make-assembly</id> |
|
||||
<phase>package</phase> |
|
||||
<goals> |
|
||||
<goal>single</goal> |
|
||||
</goals> |
|
||||
</execution> |
|
||||
</executions> |
|
||||
</plugin> |
|
||||
</plugins> |
|
||||
</build> |
|
||||
</project> |
|
||||
@ -1,31 +0,0 @@ |
|||||
package com.example.datacollect; |
|
||||
|
|
||||
import com.example.datacollect.controller.CrawlerController; |
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
public class Main { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(Main.class); |
|
||||
|
|
||||
public static void main(String[] args) { |
|
||||
logger.info("Starting CLI Crawler application"); |
|
||||
|
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
ArticleRepository repository = new ArticleRepository(); |
|
||||
CrawlerController controller = new CrawlerController(view, repository); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler (W11)! Type help for commands."); |
|
||||
logger.info("Application started successfully"); |
|
||||
|
|
||||
while (true) { |
|
||||
try { |
|
||||
controller.handle(view.readLine()); |
|
||||
} catch (Exception e) { |
|
||||
logger.error("Error processing command", e); |
|
||||
view.printError("Error: " + e.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,106 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.strategy.CrawlStrategy; |
|
||||
import com.example.datacollect.strategy.StrategyFactory; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.List; |
|
||||
|
|
||||
public class AnalyzeCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(AnalyzeCommand.class); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public AnalyzeCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "analyze"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
logger.debug("Executing analyze command"); |
|
||||
|
|
||||
if (args.length >= 2) { |
|
||||
String url = args[1]; |
|
||||
analyzeUrl(url); |
|
||||
} else { |
|
||||
analyzeRepository(repository); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void analyzeUrl(String url) { |
|
||||
logger.info("Analyzing URL: {}", url); |
|
||||
CrawlStrategy strategy = StrategyFactory.getStrategy(url); |
|
||||
|
|
||||
if (strategy == null) { |
|
||||
logger.error("No strategy found for URL: {}", url); |
|
||||
view.printError("No strategy found for URL: " + url); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
view.printInfo("Analyzing URL: " + url); |
|
||||
view.printInfo("Using strategy: " + strategy.getClass().getSimpleName()); |
|
||||
|
|
||||
List<Article> articles = strategy.crawl(url); |
|
||||
|
|
||||
printAnalysis(articles); |
|
||||
logger.info("Analysis completed for URL: {}", url); |
|
||||
view.printInfo("Note: Analysis results are NOT stored."); |
|
||||
} |
|
||||
|
|
||||
private void analyzeRepository(ArticleRepository repository) { |
|
||||
List<Article> articles = repository.getAll(); |
|
||||
|
|
||||
if (articles.isEmpty()) { |
|
||||
logger.info("No articles to analyze"); |
|
||||
view.printInfo("No articles to analyze. Use 'analyze <url>' to analyze a URL without storing."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.info("Analyzing {} articles from repository", articles.size()); |
|
||||
view.printInfo("Analyzing " + articles.size() + " articles from repository:"); |
|
||||
printAnalysis(articles); |
|
||||
} |
|
||||
|
|
||||
private void printAnalysis(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
logger.info("No articles found for analysis"); |
|
||||
view.printInfo("No articles found."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
int totalArticles = articles.size(); |
|
||||
int totalContentLength = 0; |
|
||||
int articlesWithAuthor = 0; |
|
||||
int articlesWithDate = 0; |
|
||||
|
|
||||
for (Article article : articles) { |
|
||||
if (article.getContent() != null) { |
|
||||
totalContentLength += article.getContent().length(); |
|
||||
} |
|
||||
if (article.getAuthor() != null && !article.getAuthor().isEmpty()) { |
|
||||
articlesWithAuthor++; |
|
||||
} |
|
||||
if (article.getPublishDate() != null) { |
|
||||
articlesWithDate++; |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
double avgContentLength = totalArticles > 0 ? (double) totalContentLength / totalArticles : 0; |
|
||||
|
|
||||
logger.info("Analysis results: {} articles, {} avg length", totalArticles, avgContentLength); |
|
||||
view.printInfo("=== Analysis Results ==="); |
|
||||
view.printInfo("Total articles: " + totalArticles); |
|
||||
view.printInfo("Total content length: " + totalContentLength); |
|
||||
view.printInfo("Average content length: " + String.format("%.2f", avgContentLength)); |
|
||||
view.printInfo("Articles with author: " + articlesWithAuthor); |
|
||||
view.printInfo("Articles with publish date: " + articlesWithDate); |
|
||||
} |
|
||||
} |
|
||||
@ -1,9 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
@ -1,61 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.service.ScraperService; |
|
||||
import com.example.datacollect.strategy.CrawlStrategy; |
|
||||
import com.example.datacollect.strategy.StrategyFactory; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.List; |
|
||||
|
|
||||
public class CrawlCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(CrawlCommand.class); |
|
||||
private final ConsoleView view; |
|
||||
private final ScraperService scraperService; |
|
||||
|
|
||||
public CrawlCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
this.scraperService = new ScraperService(); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "crawl"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
if (args.length < 2) { |
|
||||
logger.warn("Missing URL argument"); |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
String url = args[1]; |
|
||||
logger.info("Crawl started for: {}", url); |
|
||||
|
|
||||
CrawlStrategy strategy = StrategyFactory.getStrategy(url); |
|
||||
|
|
||||
if (strategy == null) { |
|
||||
logger.error("No strategy found for URL: {}", url); |
|
||||
view.printError("No strategy found for URL: " + url); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.info("Using strategy: {}", strategy.getClass().getSimpleName()); |
|
||||
view.printInfo("Crawling " + url + " with strategy: " + strategy.getClass().getSimpleName()); |
|
||||
|
|
||||
try { |
|
||||
List<Article> articles = scraperService.scrapeWithRetry(strategy, url); |
|
||||
repository.addAll(articles); |
|
||||
logger.info("Crawled {} articles successfully", articles.size()); |
|
||||
view.printSuccess("Crawled " + articles.size() + " articles"); |
|
||||
} catch (Exception e) { |
|
||||
logger.error("Error crawling URL: {}", url, e); |
|
||||
view.printError("Error: " + e.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,27 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
public class ExitCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(ExitCommand.class); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ExitCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "exit"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
logger.info("User requested exit"); |
|
||||
view.printSuccess("Goodbye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
@ -1,32 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
public class HelpCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(HelpCommand.class); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HelpCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "help"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
logger.debug("Executing help command"); |
|
||||
view.printInfo("Commands:"); |
|
||||
view.printInfo(" crawl <url> - 爬取指定 URL 的文章"); |
|
||||
view.printInfo(" list - 列出已爬取的文章"); |
|
||||
view.printInfo(" analyze - 分析文章统计信息"); |
|
||||
view.printInfo(" history - 显示命令历史记录"); |
|
||||
view.printInfo(" help - 显示此帮助信息"); |
|
||||
view.printInfo(" exit - 退出程序"); |
|
||||
} |
|
||||
} |
|
||||
@ -1,55 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class HistoryCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(HistoryCommand.class); |
|
||||
private static final List<String> commandHistory = new ArrayList<>(); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HistoryCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "history"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
logger.debug("Executing history command"); |
|
||||
|
|
||||
if (commandHistory.isEmpty()) { |
|
||||
logger.info("Command history is empty"); |
|
||||
view.printInfo("No command history."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.info("Showing {} command history items", commandHistory.size()); |
|
||||
view.printInfo("Command History:"); |
|
||||
for (int i = 0; i < commandHistory.size(); i++) { |
|
||||
view.printInfo((i + 1) + ". " + commandHistory.get(i)); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
public static void addCommand(String command) { |
|
||||
commandHistory.add(command); |
|
||||
logger.debug("Command added to history: {}", command); |
|
||||
} |
|
||||
|
|
||||
public static List<String> getCommandHistory() { |
|
||||
return new ArrayList<>(commandHistory); |
|
||||
} |
|
||||
|
|
||||
public static void clearHistory() { |
|
||||
commandHistory.clear(); |
|
||||
logger.info("Command history cleared"); |
|
||||
} |
|
||||
} |
|
||||
@ -1,41 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ListCommand implements Command { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(ListCommand.class); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ListCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "list"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, ArticleRepository repository) { |
|
||||
logger.debug("Executing list command"); |
|
||||
List<Article> articles = repository.getAll(); |
|
||||
|
|
||||
if (articles.isEmpty()) { |
|
||||
logger.info("No articles found"); |
|
||||
view.printInfo("No articles yet. Use 'crawl <url>' to get started."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.info("Listing {} articles", articles.size()); |
|
||||
view.printInfo("=== Articles (" + articles.size() + ") ==="); |
|
||||
for (Article article : articles) { |
|
||||
view.printInfo(article.toString()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,59 +0,0 @@ |
|||||
package com.example.datacollect.controller; |
|
||||
|
|
||||
import com.example.datacollect.command.*; |
|
||||
import com.example.datacollect.repository.ArticleRepository; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.HashMap; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(CrawlerController.class); |
|
||||
private final Map<String, Command> commands = new HashMap<>(); |
|
||||
private final ConsoleView view; |
|
||||
private final ArticleRepository repository; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, ArticleRepository repository) { |
|
||||
this.view = view; |
|
||||
this.repository = repository; |
|
||||
logger.info("Initializing CrawlerController with {} commands", 6); |
|
||||
register(new HelpCommand(view)); |
|
||||
register(new ListCommand(view)); |
|
||||
register(new CrawlCommand(view)); |
|
||||
register(new ExitCommand(view)); |
|
||||
register(new HistoryCommand(view)); |
|
||||
register(new AnalyzeCommand(view)); |
|
||||
logger.info("CrawlerController initialized successfully"); |
|
||||
} |
|
||||
|
|
||||
private void register(Command command) { |
|
||||
commands.put(command.getName(), command); |
|
||||
logger.debug("Registered command: {}", command.getName()); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
String text = input == null ? "" : input.trim(); |
|
||||
if (text.isEmpty()) { |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.debug("Handling input: {}", text); |
|
||||
|
|
||||
// 记录命令历史
|
|
||||
HistoryCommand.addCommand(text); |
|
||||
|
|
||||
String[] args = text.split("\\s+"); |
|
||||
String cmdName = args[0].toLowerCase(); |
|
||||
Command command = commands.get(cmdName); |
|
||||
if (command == null) { |
|
||||
logger.warn("Unknown command: {}", cmdName); |
|
||||
view.printError("Unknown command: " + cmdName); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
logger.info("Executing command: {}", cmdName); |
|
||||
command.execute(args, repository); |
|
||||
} |
|
||||
} |
|
||||
@ -1,11 +0,0 @@ |
|||||
package com.example.datacollect.exception; |
|
||||
|
|
||||
public class CrawlerException extends RuntimeException { |
|
||||
public CrawlerException(String message) { |
|
||||
super(message); |
|
||||
} |
|
||||
|
|
||||
public CrawlerException(String message, Throwable cause) { |
|
||||
super(message, cause); |
|
||||
} |
|
||||
} |
|
||||
@ -1,11 +0,0 @@ |
|||||
package com.example.datacollect.exception; |
|
||||
|
|
||||
public class NetworkException extends CrawlerException { |
|
||||
public NetworkException(String message) { |
|
||||
super(message); |
|
||||
} |
|
||||
|
|
||||
public NetworkException(String message, Throwable cause) { |
|
||||
super(message, cause); |
|
||||
} |
|
||||
} |
|
||||
@ -1,11 +0,0 @@ |
|||||
package com.example.datacollect.exception; |
|
||||
|
|
||||
public class ParseException extends CrawlerException { |
|
||||
public ParseException(String message) { |
|
||||
super(message); |
|
||||
} |
|
||||
|
|
||||
public ParseException(String message, Throwable cause) { |
|
||||
super(message, cause); |
|
||||
} |
|
||||
} |
|
||||
@ -1,75 +0,0 @@ |
|||||
package com.example.datacollect.model; |
|
||||
|
|
||||
import java.time.LocalDate; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
private String author; |
|
||||
private LocalDate publishDate; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public Article(String title, String url, String content, String author, LocalDate publishDate) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
this.author = author; |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { |
|
||||
return title; |
|
||||
} |
|
||||
|
|
||||
public void setTitle(String title) { |
|
||||
this.title = title; |
|
||||
} |
|
||||
|
|
||||
public String getUrl() { |
|
||||
return url; |
|
||||
} |
|
||||
|
|
||||
public void setUrl(String url) { |
|
||||
this.url = url; |
|
||||
} |
|
||||
|
|
||||
public String getContent() { |
|
||||
return content; |
|
||||
} |
|
||||
|
|
||||
public void setContent(String content) { |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getAuthor() { |
|
||||
return author; |
|
||||
} |
|
||||
|
|
||||
public void setAuthor(String author) { |
|
||||
this.author = author; |
|
||||
} |
|
||||
|
|
||||
public LocalDate getPublishDate() { |
|
||||
return publishDate; |
|
||||
} |
|
||||
|
|
||||
public void setPublishDate(LocalDate publishDate) { |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{" |
|
||||
+ "title='" + title + '\'' |
|
||||
+ ", url='" + url + '\'' |
|
||||
+ ", author='" + author + '\'' |
|
||||
+ ", publishDate=" + publishDate |
|
||||
+ '}'; |
|
||||
} |
|
||||
} |
|
||||
@ -1,52 +0,0 @@ |
|||||
package com.example.datacollect.repository; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.ArrayList; |
|
||||
import java.util.Collections; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ArticleRepository { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(ArticleRepository.class); |
|
||||
private final List<Article> articles = new ArrayList<>(); |
|
||||
|
|
||||
public void add(Article article) { |
|
||||
if (article == null) { |
|
||||
logger.warn("Attempted to add null article"); |
|
||||
return; |
|
||||
} |
|
||||
if (article.getTitle() == null || article.getTitle().isEmpty()) { |
|
||||
logger.warn("Attempted to add article with empty title"); |
|
||||
return; |
|
||||
} |
|
||||
articles.add(article); |
|
||||
logger.debug("Added article: {}", article.getTitle()); |
|
||||
} |
|
||||
|
|
||||
public void addAll(List<Article> articleList) { |
|
||||
if (articleList == null) { |
|
||||
logger.warn("Attempted to add null article list"); |
|
||||
return; |
|
||||
} |
|
||||
for (Article article : articleList) { |
|
||||
add(article); |
|
||||
} |
|
||||
logger.info("Added {} articles", articleList.size()); |
|
||||
} |
|
||||
|
|
||||
public List<Article> getAll() { |
|
||||
return Collections.unmodifiableList(articles); |
|
||||
} |
|
||||
|
|
||||
public void clear() { |
|
||||
int size = articles.size(); |
|
||||
articles.clear(); |
|
||||
logger.info("Cleared {} articles from repository", size); |
|
||||
} |
|
||||
|
|
||||
public int size() { |
|
||||
return articles.size(); |
|
||||
} |
|
||||
} |
|
||||
@ -1,56 +0,0 @@ |
|||||
package com.example.datacollect.service; |
|
||||
|
|
||||
import com.example.datacollect.exception.CrawlerException; |
|
||||
import com.example.datacollect.exception.NetworkException; |
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.strategy.CrawlStrategy; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ScraperService { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(ScraperService.class); |
|
||||
|
|
||||
private static final int MAX_RETRY = 3; |
|
||||
private static final long INITIAL_DELAY_MS = 1000; |
|
||||
private static final double BACKOFF_MULTIPLIER = 2.0; |
|
||||
|
|
||||
public List<Article> scrapeWithRetry(CrawlStrategy strategy, String url) { |
|
||||
int attempt = 0; |
|
||||
long delay = INITIAL_DELAY_MS; |
|
||||
|
|
||||
while (attempt < MAX_RETRY) { |
|
||||
try { |
|
||||
attempt++; |
|
||||
logger.info("Attempt {}/{} to crawl {}", attempt, MAX_RETRY, url); |
|
||||
|
|
||||
List<Article> articles = strategy.crawl(url); |
|
||||
|
|
||||
if (attempt > 1) { |
|
||||
logger.info("Successfully crawled {} on attempt {}", url, attempt); |
|
||||
} |
|
||||
return articles; |
|
||||
|
|
||||
} catch (NetworkException e) { |
|
||||
logger.warn("Network error on attempt {} for {}: {}", attempt, url, e.getMessage()); |
|
||||
|
|
||||
if (attempt < MAX_RETRY) { |
|
||||
try { |
|
||||
logger.info("Retrying after {}ms...", delay); |
|
||||
Thread.sleep(delay); |
|
||||
delay = (long) (delay * BACKOFF_MULTIPLIER); |
|
||||
} catch (InterruptedException ie) { |
|
||||
Thread.currentThread().interrupt(); |
|
||||
throw new CrawlerException("Interrupted during retry wait", ie); |
|
||||
} |
|
||||
} else { |
|
||||
logger.error("Failed to crawl {} after {} attempts due to network errors", url, MAX_RETRY); |
|
||||
throw new CrawlerException("Failed to crawl " + url + " after " + MAX_RETRY + " attempts", e); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
throw new CrawlerException("Unexpected error: max retry attempts exhausted"); |
|
||||
} |
|
||||
} |
|
||||
@ -1,93 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.exception.NetworkException; |
|
||||
import com.example.datacollect.exception.ParseException; |
|
||||
import org.jsoup.Jsoup; |
|
||||
import org.jsoup.nodes.Document; |
|
||||
import org.jsoup.nodes.Element; |
|
||||
import org.jsoup.select.Elements; |
|
||||
|
|
||||
import java.io.IOException; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class BlogStrategy implements CrawlStrategy { |
|
||||
@Override |
|
||||
public boolean supports(String url) { |
|
||||
return url != null && (url.contains("blog") || url.contains("wordpress") || url.contains("lofter") || url.contains("hexo")); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> crawl(String url) { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url) |
|
||||
.userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36") |
|
||||
.timeout(10000) |
|
||||
.get(); |
|
||||
articles = parse(doc, url); |
|
||||
} catch (IOException e) { |
|
||||
throw new NetworkException("网络请求失败：" + e.getMessage(), e); |
|
||||
} catch (ParseException e) { |
|
||||
throw e; |
|
||||
} catch (Exception e) { |
|
||||
articles.add(new Article("爬取失败", url, "错误：" + e.getMessage(), "系统", null)); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> parse(Document doc, String url) throws ParseException { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
if (url.contains("lofter")) { |
|
||||
crawlLofter(doc, url, articles); |
|
||||
} else if (url.contains("wordpress")) { |
|
||||
crawlWordpress(doc, url, articles); |
|
||||
} else { |
|
||||
crawlGenericBlog(doc, url, articles); |
|
||||
} |
|
||||
} catch (Exception e) { |
|
||||
throw new ParseException("解析博客网站失败：" + e.getMessage(), e); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
private void crawlLofter(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".m-post"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select(".m-post-title a").text(); |
|
||||
String link = item.select(".m-post-title a").attr("href"); |
|
||||
String author = item.select(".m-user-name").text(); |
|
||||
String summary = item.select(".m-post-content").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary.length() > 300 ? summary.substring(0, 300) : summary, author, null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlWordpress(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".post"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select(".entry-title a").text(); |
|
||||
String link = item.select(".entry-title a").attr("href"); |
|
||||
String author = item.select(".author").text(); |
|
||||
String summary = item.select(".entry-summary").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary.length() > 300 ? summary.substring(0, 300) : summary, author, null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlGenericBlog(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".article, .post, .blog-post"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select("h1, h2, .title").text(); |
|
||||
String content = item.select(".content, .post-content").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, url, content.length() > 300 ? content.substring(0, 300) : content, "未知作者", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,12 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.exception.ParseException; |
|
||||
import org.jsoup.nodes.Document; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface CrawlStrategy { |
|
||||
boolean supports(String url); |
|
||||
List<Article> crawl(String url); |
|
||||
List<Article> parse(Document doc, String url) throws ParseException; |
|
||||
} |
|
||||
@ -1,118 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.exception.NetworkException; |
|
||||
import com.example.datacollect.exception.ParseException; |
|
||||
import org.jsoup.Jsoup; |
|
||||
import org.jsoup.nodes.Document; |
|
||||
import org.jsoup.nodes.Element; |
|
||||
import org.jsoup.select.Elements; |
|
||||
|
|
||||
import java.io.IOException; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class NewsStrategy implements CrawlStrategy { |
|
||||
@Override |
|
||||
public boolean supports(String url) { |
|
||||
return url != null && (url.contains("news") || url.contains("sina") || url.contains("163") || url.contains("sohu") || url.contains("qq.com")); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> crawl(String url) { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url) |
|
||||
.userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36") |
|
||||
.timeout(10000) |
|
||||
.get(); |
|
||||
articles = parse(doc, url); |
|
||||
} catch (IOException e) { |
|
||||
throw new NetworkException("网络请求失败：" + e.getMessage(), e); |
|
||||
} catch (ParseException e) { |
|
||||
throw e; |
|
||||
} catch (Exception e) { |
|
||||
articles.add(new Article("爬取失败", url, "错误：" + e.getMessage(), "系统", null)); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> parse(Document doc, String url) throws ParseException { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
if (url.contains("sina")) { |
|
||||
crawlSina(doc, url, articles); |
|
||||
} else if (url.contains("163") || url.contains("netease")) { |
|
||||
crawlNetease(doc, url, articles); |
|
||||
} else if (url.contains("sohu")) { |
|
||||
crawlSohu(doc, url, articles); |
|
||||
} else if (url.contains("qq")) { |
|
||||
crawlQQ(doc, url, articles); |
|
||||
} else { |
|
||||
crawlGenericNews(doc, url, articles); |
|
||||
} |
|
||||
} catch (Exception e) { |
|
||||
throw new ParseException("解析新闻网站失败：" + e.getMessage(), e); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
private void crawlSina(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".news-item"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select("a").text(); |
|
||||
String link = item.select("a").attr("href"); |
|
||||
String summary = item.select(".news-summary").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary.length() > 300 ? summary.substring(0, 300) : summary, "新浪新闻", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlNetease(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".news-list li"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select("a").text(); |
|
||||
String link = item.select("a").attr("href"); |
|
||||
if (!link.startsWith("http")) link = "https://news.163.com" + link; |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, "", "网易新闻", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlSohu(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".news-item h3 a"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.text(); |
|
||||
String link = item.attr("href"); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, "", "搜狐新闻", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlQQ(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".list li a"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.text(); |
|
||||
String link = item.attr("href"); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, "", "腾讯新闻", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlGenericNews(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".news, .article-item"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select("h2, h3, .title").text(); |
|
||||
String link = item.select("a").attr("href"); |
|
||||
if (!link.startsWith("http")) link = url + link; |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, "", "新闻网站", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,27 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class StrategyFactory { |
|
||||
private static final List<CrawlStrategy> strategies = new ArrayList<>(); |
|
||||
|
|
||||
static { |
|
||||
strategies.add(new BlogStrategy()); |
|
||||
strategies.add(new NewsStrategy()); |
|
||||
strategies.add(new TechStrategy()); |
|
||||
} |
|
||||
|
|
||||
public static CrawlStrategy getStrategy(String url) { |
|
||||
for (CrawlStrategy strategy : strategies) { |
|
||||
if (strategy.supports(url)) { |
|
||||
return strategy; |
|
||||
} |
|
||||
} |
|
||||
return null; |
|
||||
} |
|
||||
|
|
||||
public static List<CrawlStrategy> getAllStrategies() { |
|
||||
return new ArrayList<>(strategies); |
|
||||
} |
|
||||
} |
|
||||
@ -1,105 +0,0 @@ |
|||||
package com.example.datacollect.strategy; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.exception.NetworkException; |
|
||||
import com.example.datacollect.exception.ParseException; |
|
||||
import org.jsoup.Jsoup; |
|
||||
import org.jsoup.nodes.Document; |
|
||||
import org.jsoup.nodes.Element; |
|
||||
import org.jsoup.select.Elements; |
|
||||
|
|
||||
import java.io.IOException; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class TechStrategy implements CrawlStrategy { |
|
||||
@Override |
|
||||
public boolean supports(String url) { |
|
||||
return url != null && (url.contains("csdn") || url.contains("oschina") || url.contains("iteye") || url.contains("cnblogs")); |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> crawl(String url) { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url) |
|
||||
.userAgent("Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36") |
|
||||
.timeout(10000) |
|
||||
.get(); |
|
||||
articles = parse(doc, url); |
|
||||
} catch (IOException e) { |
|
||||
throw new NetworkException("网络请求失败：" + e.getMessage(), e); |
|
||||
} catch (ParseException e) { |
|
||||
throw e; |
|
||||
} catch (Exception e) { |
|
||||
articles.add(new Article("爬取失败", url, "错误：" + e.getMessage(), "系统", null)); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public List<Article> parse(Document doc, String url) throws ParseException { |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
try { |
|
||||
if (url.contains("csdn")) { |
|
||||
crawlCsdn(doc, url, articles); |
|
||||
} else if (url.contains("cnblogs")) { |
|
||||
crawlCnblogs(doc, url, articles); |
|
||||
} else if (url.contains("oschina")) { |
|
||||
crawlOschina(doc, url, articles); |
|
||||
} else { |
|
||||
crawlGeneric(doc, url, articles); |
|
||||
} |
|
||||
} catch (Exception e) { |
|
||||
throw new ParseException("解析技术网站失败：" + e.getMessage(), e); |
|
||||
} |
|
||||
return articles; |
|
||||
} |
|
||||
|
|
||||
private void crawlCsdn(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".article-item-box"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select("h4 a").text(); |
|
||||
String link = item.select("h4 a").attr("href"); |
|
||||
String author = item.select(".name").text(); |
|
||||
String summary = item.select(".content").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary, author, null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlCnblogs(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".post-item"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select(".post-item-title a").text(); |
|
||||
String link = item.select(".post-item-title a").attr("href"); |
|
||||
String author = item.select(".post-item-author a").text(); |
|
||||
String summary = item.select(".post-item-summary").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary, author, null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlOschina(Document doc, String url, List<Article> articles) { |
|
||||
Elements items = doc.select(".news-list .news-item"); |
|
||||
for (Element item : items) { |
|
||||
String title = item.select(".title a").text(); |
|
||||
String link = "https://www.oschina.net" + item.select(".title a").attr("href"); |
|
||||
String author = item.select(".author").text(); |
|
||||
String summary = item.select(".description").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, link, summary, author, null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
private void crawlGeneric(Document doc, String url, List<Article> articles) { |
|
||||
String title = doc.title(); |
|
||||
String content = doc.select("article, .article-content, .post-content").text(); |
|
||||
if (!title.isEmpty()) { |
|
||||
articles.add(new Article(title, url, content.length() > 500 ? content.substring(0, 500) : content, "未知", null)); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,53 +0,0 @@ |
|||||
package com.example.datacollect.view; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import org.slf4j.Logger; |
|
||||
import org.slf4j.LoggerFactory; |
|
||||
|
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
private static final Logger logger = LoggerFactory.getLogger(ConsoleView.class); |
|
||||
private static final String ANSI_RESET = "\u001B[0m"; |
|
||||
private static final String ANSI_GREEN = "\u001B[32m"; |
|
||||
private static final String ANSI_RED = "\u001B[31m"; |
|
||||
private static final String ANSI_BLUE = "\u001B[34m"; |
|
||||
|
|
||||
private final Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("> "); |
|
||||
String line = scanner.nextLine(); |
|
||||
logger.debug("User input: {}", line); |
|
||||
return line; |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
logger.info("Success: {}", msg); |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
logger.error("Error: {}", msg); |
|
||||
System.out.println(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
logger.debug("Info: {}", msg); |
|
||||
System.out.println(ANSI_BLUE + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
logger.info("No articles to display"); |
|
||||
printInfo("暂无文章，请先执行 crawl。"); |
|
||||
return; |
|
||||
} |
|
||||
logger.info("Displaying {} articles", articles.size()); |
|
||||
for (int i = 0; i < articles.size(); i++) { |
|
||||
Article a = articles.get(i); |
|
||||
System.out.println((i + 1) + ". " + a.getTitle() + " | " + a.getUrl()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,22 +0,0 @@ |
|||||
<configuration> |
|
||||
<appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender"> |
|
||||
<encoder> |
|
||||
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern> |
|
||||
</encoder> |
|
||||
</appender> |
|
||||
|
|
||||
<appender name="FILE" class="ch.qos.logback.core.FileAppender"> |
|
||||
<file>logs/crawler.log</file> |
|
||||
<encoder> |
|
||||
<pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern> |
|
||||
</encoder> |
|
||||
</appender> |
|
||||
|
|
||||
<root level="INFO"> |
|
||||
<appender-ref ref="CONSOLE" /> |
|
||||
<appender-ref ref="FILE" /> |
|
||||
</root> |
|
||||
|
|
||||
<logger name="com.example.datacollect" level="DEBUG" /> |
|
||||
<logger name="org.jsoup" level="WARN" /> |
|
||||
</configuration> |
|
||||
@ -1,758 +0,0 @@ |
|||||
--- |
|
||||
|
|
||||
# 教案：《高级程序设计》第9周——工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
| 项目 | 内容 | |
|
||||
|------|------| |
|
||||
| **课程名称** | 高级程序设计 | |
|
||||
| **周次** | 第9周 | |
|
||||
| **主题** | 工程架构——从"写代码"到"造系统" | |
|
||||
| **学时** | 2学时（90分钟） | |
|
||||
| **授课对象** | 具备Python基础、已完成Java面向对象特性学习的学生 | |
|
||||
| **教学环境** | JDK 17+、IntelliJ IDEA、Maven（模板） | |
|
||||
| **前情提要** | 本课程原计划使用JavaFX GUI，后根据教学反馈转向CLI + MVC + 爬虫工程化 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 教学调整说明：为什么选择CLI而不是GUI？ |
|
||||
|
|
||||
> **原计划**：JavaFX桌面应用 → **新计划**：CLI命令行应用 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **学生痛点** | "窗口点击"与后端能力无关 | 真正锻炼工程思维 | |
|
||||
| **AI辅助** | AI生成FXML，学生看不懂 | AI辅助重构架构 | |
|
||||
| **工程化** | 脱离真实后端开发场景 | 模拟真实服务器/大数据开发 | |
|
||||
| **核心转型** | "视觉装饰"优先 | "逻辑架构"优先 | |
|
||||
|
|
||||
**决策理由**： |
|
||||
1. **985学生需要的是工程思维**，不是拖控件 |
|
||||
2. **接口抽象**是弱项，CLI + MVC更能暴露这个问题 |
|
||||
3. **彩色终端**足够酷炫，且代码量可控 |
|
||||
|
|
||||
**更深层的教育价值**： |
|
||||
> 在GUI框架中，架构已被框架强制划定，学生只是"遵守规矩"；而CLI世界里没有任何框架告诉你模型在哪、视图在哪——**当外部约束消失，内部的工程纪律才真正建立**。这正是本节课要传递的核心精神。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 一、教学目标 |
|
||||
|
|
||||
| 目标维度 | 具体描述 | |
|
||||
|----------|----------| |
|
||||
| **知识掌握** | 理解MVC架构的职责划分及其演化脉络；掌握Maven项目结构与pom.xml基础；理解Command模式的路由原理。 | |
|
||||
| **工程实践** | 能搭建规范的Maven项目包结构；能实现基于Scanner的控制台交互；能用Command接口实现可扩展的命令路由；能识别架构中的"越权行为"。 | |
|
||||
| **思维转型** | 从"一个类写全部"转向"分层解耦"；从"修改现有代码"转向"新增类实现功能"；从"满足功能"转向"代码的工程洁癖"。 | |
|
||||
| **工具应用** | 利用AI辅助审查MVC职责越权；让AI扮演"架构审计师"检查分层是否清晰；理解AI生成代码中的架构缺陷。 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 二、教学重点与难点 |
|
||||
|
|
||||
| 项目 | 内容 | 突破方法 | |
|
||||
|------|------|----------| |
|
||||
| **重点** | MVC三层职责划分、CLI交互实现、Command接口解耦、代码中的工程细节（常量、输出归属） | 以"新增命令需要改什么"为切入点，展示Command模式的优势；通过现场"代码找茬"强化细节意识 | |
|
||||
| **难点** | Controller不写业务逻辑、Command接口的多态实现、共享数据模型的设计缺陷识别 | 现场演示：增加一个命令只需新建类，无需修改Controller；暴露`List<Article>`共享引用的问题并预告解决方案 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三、教学过程设计（90分钟） |
|
||||
|
|
||||
| 环节 | 时间 | 教学内容 | 师生活动 | AI协同点 | |
|
||||
|------|------|----------|----------|----------| |
|
||||
| **1. 痛点引入：从脚本到工程的鸿沟** | 10' | 展示"意大利面"式爬虫代码，演示改一处需要动全身 | **教师演示**：现场展示一段混乱代码，让学生找问题 | 用AI分析代码耦合度 | |
|
||||
| **2. CLI vs GUI：架构选择的思考** | 10' | 对比两种方案的优缺点，解释为什么CLI更适合培养工程思维 | **教师讲解**：用对比表格说明选择CLI的理由 | — | |
|
||||
| **3. MVC分层设计** | 20' | 讲解Model/View/Controller三层职责，用"餐厅类比"强化理解，随后批判类比局限性 | **教师讲解**：配合架构图讲解三层交互，引导学生寻找类比破绽 | 用AI生成MVC职责对照表 | |
|
||||
| **4. Command模式：可扩展的命令路由** | 15' | 引入Command接口，解释"一个命令就是一个类" | **类比**：Command像酒店的服务部门，Controller是前台 | 让AI解释Command模式的多态原理 | |
|
||||
| **5. Maven模板与环境** | 5' | 直接使用提供的Maven模板，讲解目录结构 | **教师演示**：解压模板 → IDEA打开 → 运行 | — | |
|
||||
| **6. 三层代码落地** | 20' | **Model**：Article实体<br>**View**：ConsoleView（ANSI常量）<br>**Command接口**+实现<br>**Controller**：Map路由 | **教师演示**：分步写出代码，刻意埋入1~2个"越权细节"让学生找茬 | 学生用AI做"架构审计" | |
|
||||
| **7. 架构反思与展望** | 5' | 指出当前`List<Article>`共享引用的问题，预告W10策略模式与仓库层 | **师生互动**：你发现这个设计有什么风险？ | 让AI分析共享可变状态的危害 | |
|
||||
| **8. 实践任务：空壳程序** | 5' | 搭建完整包结构，实现CLI循环 | 学生现场编码，教师巡视 | 完成后用AI检查包结构 | |
|
||||
| **9. 总结与过渡** | 5' | 本周实现了"骨架+命令可扩展"，下周填入"灵魂"——解析器，并解决数据安全问题 | 总结Command模式优势，预告策略模式 | — | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 四、核心教学内容脚本 |
|
||||
|
|
||||
### 4.1 痛点引入：从脚本到工程的鸿沟（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "同学们，前8周我们学的是Java语法，从变量到类，从继承到接口。但有一个问题：代码写完之后，怎么组织？" |
|
||||
> |
|
||||
> "来看这段代码——这是某个同学写的'爬虫'，他一个人完成了一个'完整'的项目。" |
|
||||
|
|
||||
**展示"脚本式"代码**： |
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
|
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问引导**： |
|
||||
1. "如果我想把标题保存到文件，要改哪里？" |
|
||||
2. "如果我想支持另一个网站，它的HTML结构不一样，要怎么办？" |
|
||||
3. "如果我想让输出变成彩色，要改哪里？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "看到了吗？才60行代码，已经'牵一发而动全身'了。这就是一个'脚本'的宿命——功能全混在一起，改一个小需求，整个文件都要翻。" |
|
||||
> |
|
||||
> "这周我们要解决：**怎么让代码'改起来不疼'？**" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.2 CLI vs GUI：架构选择的思考（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "既然要写一个'完整'的爬虫应用，我们有两个选择：图形界面（GUI）或命令行界面（CLI）。为什么我推荐CLI而不是GUI？" |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **代码量** | FXML + Controller + CSS，大量模板代码 | 纯Java，代码量可控 | |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **后端能力** | 几乎无关 | 模拟真实服务器开发 | |
|
||||
| **可测试性** | 难（需要UI测试框架） | 易（直接测试Command类） | |
|
||||
| **工程思维** | 弱（关注视觉） | 强（关注逻辑） | |
|
||||
|
|
||||
**核心观点**： |
|
||||
> **CLI更需要MVC！** GUI有现成的事件系统（点击按钮→触发事件），而CLI只有字符流。**没有架构，分分钟写成脚本**。MVC在CLI里是"刚需"，不是"装饰"。 |
|
||||
> |
|
||||
> **更深一层**：在GUI里，框架已经硬塞给你一套架构，你只是在填空；但在CLI里，所有结构都必须由你亲手搭建。**当外部约束消失，内部的工程纪律才真正开始建立**——这才是本节课的真正目的。 |
|
||||
|
|
||||
**CLI也能很酷**： |
|
||||
- ANSI彩色输出（红/绿/黄/蓝） |
|
||||
- 表格展示数据 |
|
||||
- 进度条动画 |
|
||||
- 模拟真实大数据开发场景 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.3 MVC分层设计（20分钟） |
|
||||
|
|
||||
#### 4.3.1 MVC的起源与演进 |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "MVC不是新东西，它是1970年代为桌面应用设计的架构思想。但它的核心——'职责分离'——在任何软件里都适用。" |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
#### 4.3.2 从GUI到CLI的映射 |
|
||||
|
|
||||
| GUI组件 | CLI对应 | 说明 | |
|
||||
|--------|--------|------| |
|
||||
| 窗口/按钮 | 命令行输入 | **View = 用户交互** | |
|
||||
| 数据模型 | Article实体类 | **Model = 数据结构** | |
|
||||
| 事件监听 | Command路由 | **Controller = 调度** | |
|
||||
|
|
||||
#### 4.3.3 MVC三层职责 |
|
||||
|
|
||||
**架构图示**： |
|
||||
|
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
│ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ - 接收命令（crawl, help, exit） │ |
|
||||
│ - 分发给对应的Command │ |
|
||||
│ 【口诀】：Controller不管"怎么做"， │ |
|
||||
│ 只管"派给谁" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
│ │ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ - 数据实体 │ │ - 输入解析 │ |
|
||||
│ - 业务逻辑 │ │ - 输出格式化 │ |
|
||||
│ 【口诀】： │ │ 【口诀】： │ |
|
||||
│ Model管"数据" │ │ View管"呈现" │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
**三层职责详解** |
|
||||
|
|
||||
| 层级 | 职责 | 典型代码 | 禁止做什么 | |
|
||||
|------|------|----------|------------| |
|
||||
| **Model** | 数据结构 + 业务逻辑 | `class Article { String title; String content; }` | 不能有`System.out.println`，不能有`Scanner` | |
|
||||
| **View** | 接收用户输入 + 格式化输出 | `class ConsoleView { String readInput(); void print(String); }` | 不能写爬虫逻辑，只做"传声筒" | |
|
||||
| **Controller** | 协调调度 | `class CrawlerController { void handle(String cmd) { ... } }` | 不能直接写业务细节，委托给Command | |
|
||||
|
|
||||
#### 4.3.4 类比强化："餐厅类比" |
|
||||
|
|
||||
> "把MVC想象成一家餐厅： |
|
||||
> - **Model是后厨**：只管做菜（数据加工），不管谁来吃、怎么端 |
|
||||
> - **View是服务员**：只管端菜和收钱（输入输出），不管菜怎么做 |
|
||||
> - **Controller是前台**：只管把顾客的点单传给后厨，把做好的菜端给顾客 |
|
||||
> |
|
||||
> 如果后厨开始管'谁来吃饭'，这餐厅就乱了。" |
|
||||
|
|
||||
#### 4.3.5 对"餐厅类比"的批判性思考（关键！） |
|
||||
|
|
||||
**教师导引**： |
|
||||
> "刚才的类比好理解吗？很好。但任何一个类比都有它的边界，如果把它当成真理，就会出问题。现在我们来给这个类比'找茬'。" |
|
||||
|
|
||||
**提问学生**： |
|
||||
1. "后厨真的完全不知道客人是谁吗？如果客人有忌口（比如不吃香菜），这个信息需不需要传到后厨？" |
|
||||
2. "服务员只是端菜吗？在真实餐厅里，服务员经常向后厨反馈'客人觉得今天的菜咸了'，这属于View→Model的反向影响吗？" |
|
||||
3. "在这个类比里，我们把前台（Controller）和后厨（Model）的关系说成单向的。但实际上，后厨做完了菜，需要通知前台'菜好了'，这不就是**观察者模式**吗？" |
|
||||
|
|
||||
**点明本质**： |
|
||||
> "实际MVC的数据流向常常是**双向**的：Controller调用Model的方法改变数据，Model变化后又通知View更新显示。只不过在本次CLI项目中，我们暂时使用'请求-响应'的单向简化模型——用户输入命令，系统处理，然后立即输出结果。这个简化版够用，但你要知道完整的MVC是更动态的。随着系统复杂，Model层需要一个专门的'仓库类'来管理数据，并通知视图刷新——这正是W10我们将要深入的内容。" |
|
||||
|
|
||||
#### 4.3.6 MVC的数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，目前暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.4 Command模式：可扩展的命令路由（15分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在引入一个设计模式——Command（命令）模式。它的核心思想是：**一个命令就是一个类**。" |
|
||||
|
|
||||
#### 4.4.1 为什么需要Command模式？ |
|
||||
|
|
||||
**演示：增加一个命令的代价（switch-case版）** |
|
||||
```java |
|
||||
// 现状代码 |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果我想增加10个命令，这个类要改多少次？" |
|
||||
- "如果我不小心删了一个case，整个程序还能跑吗？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "每加一个功能，就要在这个类里戳一个洞。**这就是'肥控制器'陷阱**——所有的逻辑都堆在Controller里，它变成了新的'意大利面'。" |
|
||||
|
|
||||
#### 4.4.2 Command模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| **Command接口** | 抽象的"订单" | `Command` 接口 | |
|
||||
| **ConcreteCommand** | 具体的订单 | `HelpCommand`、`CrawlCommand` | |
|
||||
| **Invoker** | 接单的前台 | `CrawlerController` | |
|
||||
| **Receiver** | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
#### 4.4.3 Command接口定义 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/command/Command.java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); // 命令名，如 "crawl" |
|
||||
void execute(String[] args, List<Article> articles); // 执行逻辑 |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.4.4 Controller的变革（从switch到Map） |
|
||||
|
|
||||
```java |
|
||||
// 修改后的Controller |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands; // 用Map存命令 |
|
||||
private ConsoleView view; // 持有View以输出错误 |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.commands = new HashMap<>(); |
|
||||
// 增加命令无需改Controller代码，只需在这里注册 |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmd = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command command = commands.get(cmd); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmd); // 通过View输出，而非直接System.out |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 执行命令，传入参数和文章列表 |
|
||||
command.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | execute()的多态调用 | |
|
||||
| 可测试性 | 难 | 每个Command可单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
**类比强化**： |
|
||||
> "Command模式就像**酒店的客房服务**：每个服务（清理、送餐、按摩）都是一个独立的部门。前台（Controller）只负责接电话，然后把请求'派发'给对应的部门。部门自己知道怎么干活，不需要前台教。" |
|
||||
> |
|
||||
> "如果想新增一个服务，前台只需要'登记'一下，不需要把现有部门重新装修。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.5 Maven模板与环境（5分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "这周我们不发愁pom.xml配置。我已经把 Maven 模板准备好了，你们只需要解压、打开、运行。" |
|
||||
|
|
||||
**模板使用流程**： |
|
||||
``` |
|
||||
1. 解压 [my-crawler-template.zip] |
|
||||
2. 用 IDEA 打开文件夹 |
|
||||
3. 右键 pom.xml → Maven → Reload Project |
|
||||
4. 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
**标准目录结构**： |
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/ |
|
||||
│ └── Article.java |
|
||||
├── view/ |
|
||||
│ └── ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java (接口) |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/ |
|
||||
└── CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.6 代码落地（20分钟） |
|
||||
|
|
||||
#### 4.6.1 Model层：Article实体 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/model/Article.java |
|
||||
package com.crawler.model; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { return title; } |
|
||||
public void setTitle(String title) { this.title = title; } |
|
||||
public String getUrl() { return url; } |
|
||||
public void setUrl(String url) { this.url = url; } |
|
||||
public String getContent() { return content; } |
|
||||
public void setContent(String content) { this.content = content; } |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{title='" + title + "', url='" + url + "'}"; |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.2 View层：ANSI常量集中管理（工程细节！） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/view/ConsoleView.java |
|
||||
package com.crawler.view; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
// ANSI颜色常量——集中管理，避免散落各处 |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
private static final String ANSI_CYAN = "\033[36m"; |
|
||||
private static final String ANSI_RESET = "\033[0m"; |
|
||||
|
|
||||
private Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("crawler> "); |
|
||||
return scanner.nextLine().trim(); |
|
||||
} |
|
||||
|
|
||||
public void print(String msg) { |
|
||||
System.out.println(msg); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
print(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
print(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
print(ANSI_CYAN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
// 展示文章列表 |
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("No articles yet. Use 'crawl <url>' first."); |
|
||||
return; |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
print("| Title | URL |"); |
|
||||
print("+----------+--------------------------------+"); |
|
||||
for (Article a : articles) { |
|
||||
String title = a.getTitle(); |
|
||||
if (title.length() > 10) title = title.substring(0, 10) + ".."; |
|
||||
String url = a.getUrl(); |
|
||||
if (url.length() > 30) url = url.substring(0, 27) + "..."; |
|
||||
print("| " + String.format("%-10s", title) + " | " + url + " |"); |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
printInfo("Total: " + articles.size() + " articles"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**教师提示**： |
|
||||
> "注意：所有ANSI转义码都被定义为`private static final`常量。如果把`\033[32m`散落在项目各处，一旦想调整颜色，就得满世界去改——这正是我们之前痛批的'意大利面'。**这就是工程细节**。" |
|
||||
|
|
||||
#### 4.6.3 Command接口与四个实现（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// Command.java |
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
|
|
||||
// HelpCommand.java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ListCommand.java |
|
||||
public class ListCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ListCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "list"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// CrawlCommand.java (存根) |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ExitCommand.java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); // 全部输出都通过View，绝不让System.out直接出现在这里 |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**故意埋设的"找茬点"**： |
|
||||
> "我在刚才的代码里有没有隐藏违反MVC原则的地方？`CrawlCommand`的存根里，`view.printInfo("Stub: Would crawl " + args[1]);` —— 这个字符串拼接算是"业务逻辑"吗？留给大家用AI架构审计时讨论。 |
|
||||
|
|
||||
#### 4.6.4 Controller：Map路由（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/controller/CrawlerController.java |
|
||||
package com.crawler.controller; |
|
||||
|
|
||||
import com.crawler.command.*; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
private ConsoleView view; // 持有View |
|
||||
private List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmdName = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command cmd = commands.get(cmdName); |
|
||||
if (cmd == null) { |
|
||||
view.printError("Unknown command: " + cmdName); // 错误信息也走View！ |
|
||||
return; |
|
||||
} |
|
||||
cmd.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.5 main方法：组装 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/App.java |
|
||||
package com.crawler; |
|
||||
|
|
||||
import com.crawler.controller.CrawlerController; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class App { |
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
view.printInfo("Type 'help' for commands."); |
|
||||
|
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.6 架构反思与展望：共享List<Article>的隐患（关键！） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在这个架构已经可用了。但请大家审视一下：我们所有的Command都直接拿到了`List<Article>`的引用。换句话说，任何一个命令都可以随意增、删、改这个列表。" |
|
||||
> |
|
||||
> "这就好像一家酒店，所有服务员、厨师、清洁工都能随意进出保险箱——**数据结构完全裸奔了**。" |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果CrawlCommand不小心写错了代码，把一个null塞进articles，HelpCommand会不会受影响？" |
|
||||
- "如果未来我们要在添加文章时也写入日志文件，现在的设计能优雅实现吗？还是得在所有Command里分别加日志代码？" |
|
||||
|
|
||||
**预告解决方案**： |
|
||||
> "下周，我们将引入**策略模式**和一个真正的**Model仓库层（ArticleRepository）**。这个仓库会把`List`封装起来，对外只提供`add()`、`getAll()`等安全接口。任何命令想修改数据，都必须通过仓库。这就是从'数据结构'到'模型层'的进化——我们W9先搭骨架，W10给它装上盔甲。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.7 实践任务（5分钟） |
|
||||
|
|
||||
**任务要求**： |
|
||||
1. 使用Maven模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现4个Command：help/list/crawl/exit |
|
||||
4. `list`命令能展示已抓取的文章 |
|
||||
5. 运行并测试循环 |
|
||||
6. **代码找茬（额外加分）**：找出你自己代码中是否存在`System.out`直接调用、硬编码ANSI字符串等"越权行为" |
|
||||
|
|
||||
**验收标准**： |
|
||||
- [x] Maven编译通过 |
|
||||
- [x] Command接口和4个实现分离在不同文件 |
|
||||
- [x] Controller里没有switch-case |
|
||||
- [x] 新增命令只需新建类，不改Controller |
|
||||
- [x] list命令能正确显示空列表 |
|
||||
- [x] 所有输出均通过ConsoleView完成，无直接System.out.println（main除外） |
|
||||
- [x] ANSI颜色码集中定义为View常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 五、课后作业 |
|
||||
|
|
||||
### 5.1 必做任务 |
|
||||
|
|
||||
1. **完善Article**：增加`author`、`publishDate`字段 |
|
||||
2. **★ HistoryCommand（强制作业）**： |
|
||||
- 实现`history`命令，记录用户输入过的所有命令 |
|
||||
- 使用`List<String>`存储历史（复习W8集合） |
|
||||
- 示例输出： |
|
||||
``` |
|
||||
crawler> history |
|
||||
1. help |
|
||||
2. list |
|
||||
3. crawl https://example.com |
|
||||
``` |
|
||||
3. **AI架构审计**：将类名和方法名发给AI，指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？Model层是否包含输入输出代码？View层是否越权写了业务逻辑？有没有地方直接使用了System.out或硬编码ANSI码？" |
|
||||
|
|
||||
### 5.2 选做任务 |
|
||||
|
|
||||
1. **命令别名**：给`crawl`增加别名`c`，`help`增加别名`h` |
|
||||
2. **URL验证**：检查URL格式是否以http://或https://开头 |
|
||||
3. **暗色主题**：实现不同的配色方案（利用View中的ANSI常量，只需修改一处即可） |
|
||||
4. **思考并回答**：分析`List<Article>`共享引用的潜在风险，写一段200字的小结 |
|
||||
|
|
||||
### 5.3 思考题 |
|
||||
|
|
||||
1. **Command vs switch-case**：增加10个命令，哪种方式代码改动量更小？ |
|
||||
2. **如果不用Command接口，直接用Map存命令类行不行？** 接口的意义是什么？ |
|
||||
3. **Controller里的`commands.put()`能否减少？** 提示：思考"注册机制" |
|
||||
4. **为什么ExitCommand里的`view.printSuccess("Bye!")`比直接`System.out.println`更"MVC"？** 提示：回忆View的职责 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 六、AI协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**学生执行步骤**： |
|
||||
1. 列出项目中所有类名（不含方法实现） |
|
||||
2. 将类名列表发给AI |
|
||||
3. 输入指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否清晰。Model层是否包含了不应该有的代码（Scanner/System.out）？View层是否越权写了业务逻辑？请指出任何一处直接使用System.out.println的地方，并建议如何改正。" |
|
||||
|
|
||||
**预期AI输出**： |
|
||||
- 指出哪一层有越权行为 |
|
||||
- 建议如何整改 |
|
||||
- 评价整体架构健康度 |
|
||||
|
|
||||
### 进阶AI探究（选做） |
|
||||
|
|
||||
> "假设我的Command接口中execute方法接收了一个`List<Article>`参数，请分析这种设计在工程上有什么隐患，并给出重构建议。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 七、教学反思与调整记录 |
|
||||
|
|
||||
| 日期 | 事项 | 调整内容 | |
|
||||
|------|------|----------| |
|
||||
| 2026-04-28 | 首次编写 | 基于CLI+MVC重构 | |
|
||||
| 2026-04-30 | 教授反馈 | 引入Command模式、提供Maven模板、升级AI协同比 | |
|
||||
| 2026-04-30 | 逻辑重排 | 按"问题→选择→架构→模式"顺序重写 | |
|
||||
| 2026-05-01 | v2 vs V3合并 | 融合深度改进：增加教育哲学、批判性思考、ANSI常量、共享List隐患、故意埋坑 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 附录1：Maven模板说明 |
|
||||
|
|
||||
> 老师提供`my-crawler-template.zip`压缩包，包含： |
|
||||
> - pom.xml（含Jsoup依赖） |
|
||||
> - 空的src/main/java结构 |
|
||||
> - .gitignore |
|
||||
|
|
||||
## 附录2：常见问题速查 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA不识别pom.xml | 右键 pom.xml → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → Editor → File Encodings → UTF-8 | |
|
||||
| 包名大小写 | 包名全小写，类名首字母大写 | |
|
||||
| Command找不到 | 检查是否 implements Command，是否 @Override getName() | |
|
||||
| 命令不生效 | 检查 commands.put() 是否注册了该命令 | |
|
||||
| 输出颜色乱码 | IDEA控制台需支持ANSI，Windows下建议使用Windows Terminal或调整设置 | |
|
||||
| 我的System.out为什么被老师说越权 | View层才是与用户交互的唯一出口，所有输出都应通过View，这样将来改成GUI或日志时只需改View | |
|
||||
|
|
||||
## 附录3：教学逻辑说明 |
|
||||
|
|
||||
| 顺序 | 内容 | 设计理由 | |
|
||||
|------|------|----------| |
|
||||
| 1 | 痛点引入 | 从问题出发，让学生感受"为什么需要架构" | |
|
||||
| 2 | CLI vs GUI | 解释技术选型，建立"工程思维 > 视觉装饰"的认知 | |
|
||||
| 3 | MVC分层 | 核心架构概念，理解职责分离，通过类比及批判加深理解 | |
|
||||
| 4 | Command模式 | 具体实现方式，解决"肥控制器"问题 | |
|
||||
| 5 | Maven | 工具链支持 | |
|
||||
| 6 | 代码落地 | 实践验证，刻意植入细节规范，训练工程洁癖 | |
|
||||
| 7 | 架构反思 | 暴露共享可变状态隐患，为W10策略模式+仓库层做铺垫 | |
|
||||
| 8 | 实践任务 | 现场编码验证 | |
|
||||
| 9 | 总结 | 强化认知，预告下周 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 版本说明 |
|
||||
|
|
||||
- **v1**：首次编写，CLI+MVC基础框架 |
|
||||
- **v2**：按"问题→选择→架构→模式"逻辑重排 |
|
||||
- **v3 (本版)**：融合v2结构 + V3深度改进，包含： |
|
||||
- 更深的CLI教育哲学 |
|
||||
- 餐厅类比批判性思考 |
|
||||
- ANSI常量集中管理工程细节 |
|
||||
- 全部输出走View |
|
||||
- 共享List架构隐患反思 |
|
||||
- 故意埋坑让学生找茬 |
|
||||
- W10铺垫（策略模式+仓库层） |
|
||||
@ -1,5 +0,0 @@ |
|||||
#Generated by Maven |
|
||||
#Thu Apr 30 11:50:54 CST 2026 |
|
||||
artifactId=datacollect-cli |
|
||||
groupId=com.example |
|
||||
version=0.1.0 |
|
||||
@ -1,530 +0,0 @@ |
|||||
## 高级程序设计 · 第9周 |
|
||||
|
|
||||
#### 工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
##### CLI + MVC + Command模式实战 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 📌 本周导航 |
|
||||
|
|
||||
- 痛点引入：脚本的宿命 |
|
||||
- CLI vs GUI：为什么选命令行？ |
|
||||
- MVC分层：职责分离的艺术 |
|
||||
- Command模式：可扩展的路由 |
|
||||
- Maven模板：工程化第一步 |
|
||||
- 代码落地：从接口到实现 |
|
||||
- 架构反思：共享数据的隐患 |
|
||||
- 实践任务 + 课后作业 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 1️⃣ 痛点引入：从脚本到工程的鸿沟 |
|
||||
|
|
||||
#### 这是一段“意大利面”爬虫 |
|
||||
|
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 脚本的三大痛点 |
|
||||
|
|
||||
| 需求 | 需要改哪里？ | |
|
||||
|------|--------------| |
|
||||
| 保存标题到文件 | 改 main 内部逻辑 | |
|
||||
| 支持不同网站结构 | 全部重写解析代码 | |
|
||||
| 彩色输出 | 一个一个改 print | |
|
||||
|
|
||||
> 😫 **牵一发而动全身 → 改起来疼** |
|
||||
|
|
||||
### 本周目标：**让代码“改起来不疼”** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 2️⃣ CLI vs GUI：架构选择的思考 |
|
||||
|
|
||||
### 图形界面 vs 命令行 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| 学习重心 | 布局、控件、事件 | **架构、分层、路由** | |
|
||||
| 后端能力 | 弱 | 模拟真实服务器 | |
|
||||
| 工程思维 | 弱（关注视觉） | **强（关注逻辑）** | |
|
||||
| 可测试性 | 难 | 易 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 核心观点 |
|
||||
|
|
||||
> **CLI 更需要 MVC！** |
|
||||
|
|
||||
- GUI 有现成事件系统，框架强塞给你一套架构 |
|
||||
- CLI 只有字符流 → **没有架构，分分钟写成脚本** |
|
||||
|
|
||||
> 🎯 **当外部约束消失，内部的工程纪律才真正开始建立** |
|
||||
|
|
||||
### CLI 也能很酷 |
|
||||
|
|
||||
- ANSI 彩色输出 |
|
||||
- 表格展示数据 |
|
||||
- 模拟大数据/后端开发 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 3️⃣ MVC 分层设计 |
|
||||
|
|
||||
### MVC 的起源与演进 |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
**核心不变：职责分离** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 三层职责 |
|
||||
|
|
||||
![[mvc.png]] |
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ 只管"派给谁"，不管"怎么做" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ 管"数据" │ │ 管"呈现" │ |
|
||||
│ + 业务逻辑 │ │ + 输入输出 │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三层“禁止做什么” |
|
||||
|
|
||||
| 层级 | 禁止行为 | |
|
||||
| -------------- | -------------------------------------- | |
|
||||
| **Model** | 不能有 `System.out.println`，不能有 `Scanner` | |
|
||||
| **View** | 不能写爬虫逻辑，只做“传声筒” | |
|
||||
| **Controller** | 不能直接写业务细节，委托给 Command | |
|
||||
|
|
||||
> 🔴 **越权就是架构腐败的开始** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🍽️ 餐厅类比（帮助理解） |
|
||||
|
|
||||
- **Model = 后厨**：只管做菜，不管谁来吃、怎么端 |
|
||||
- **View = 服务员**：只管端菜和收钱，不管菜怎么做 |
|
||||
- **Controller = 前台**：接单 → 派给后厨 → 叫服务员上菜 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤔 对类比的批判性思考（关键！） |
|
||||
|
|
||||
> 任何类比都有边界，不要当成真理 |
|
||||
|
|
||||
| 场景 | 暴露的问题 | |
|
||||
|------|------------| |
|
||||
| 客人有忌口（不吃香菜） | 信息需要传到后厨 → Model 可能需要知道 meta 信息 | |
|
||||
| 服务员反馈“今天的菜咸了” | View → Model 反向影响 | |
|
||||
| 后厨做完菜通知前台 | **观察者模式**，数据流可能是双向的 | |
|
||||
|
|
||||
**本课程简化模型**：请求-响应，单向流 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 4️⃣ Command 模式：可扩展的命令路由 |
|
||||
|
|
||||
### 为什么需要 Command 模式？ |
|
||||
|
|
||||
```java |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 每加一个功能，就要在这个类里戳一个洞 → **肥控制器陷阱** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| Command接口 | 抽象的“订单” | `Command` | |
|
||||
| ConcreteCommand | 具体的订单 | `HelpCommand` | |
|
||||
| Invoker | 接单的前台 | `CrawlerController` | |
|
||||
| Receiver | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 接口定义 |
|
||||
|
|
||||
```java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller 的变革：从 switch 到 Map |
|
||||
|
|
||||
```java |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
// 解析命令 → 从 Map 取 Command → 调用 execute |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> **增加新命令：只需新建类，Controller 零改动！** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 对比：switch-case vs Command |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改 Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | `execute()` 多态 | |
|
||||
| 可测试性 | 难 | 每个 Command 单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
> 🏨 **类比：酒店客房服务，前台只负责派单** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 5️⃣ Maven 模板与环境（5分钟） |
|
||||
|
|
||||
### 直接使用模板，不折腾配置 |
|
||||
|
|
||||
``` |
|
||||
my-crawler-template.zip |
|
||||
↓ 解压 + IDEA打开 |
|
||||
↓ 右键 pom.xml → Maven → Reload Project |
|
||||
↓ 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
### 标准目录结构 |
|
||||
|
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/Article.java |
|
||||
├── view/ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 6️⃣ 代码落地（分步实现） |
|
||||
|
|
||||
### Model：Article 实体 |
|
||||
|
|
||||
```java |
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
// 构造器、getter/setter、toString |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 📦 只存放数据，没有任何输入输出代码 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## View：ConsoleView（ANSI常量集中管理） |
|
||||
|
|
||||
```java |
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
// ... 其他常量 |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
public void printError(String msg) { ... } |
|
||||
public void display(List<Article> articles) { ... } |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✨ **所有颜色码集中定义 → 改主题只需改一处** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 实现示例（HelpCommand） |
|
||||
|
|
||||
```java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ⚠️ 全部输出通过 `view`，绝不让 `System.out` 直接出现在这里 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## CrawlCommand（存根，下周填坑） |
|
||||
|
|
||||
```java |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔍 **找茬点**：这里拼接字符串算是“业务逻辑”吗？留给大家用 AI 审计。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## ExitCommand |
|
||||
|
|
||||
```java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✅ 所有输出都通过 View → 将来改 GUI 只需换 View 实现 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller + main 组装 |
|
||||
|
|
||||
```java |
|
||||
// Controller 中持有 Map<String,Command> |
|
||||
// App.java 中： |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔁 完成交互循环 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 7️⃣ 架构反思：共享 List<Article> 的隐患 |
|
||||
|
|
||||
### 当前问题 |
|
||||
|
|
||||
- 所有 Command 都直接拿到 `List<Article>` 引用 |
|
||||
- 任何一个命令都可以随意增、删、改列表 |
|
||||
- 数据完全“裸奔” |
|
||||
|
|
||||
> 🚨 就像酒店所有员工都能进保险箱 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 提问 |
|
||||
|
|
||||
- 如果 `CrawlCommand` 不小心把 `null` 塞进列表，`ListCommand` 会怎样？ |
|
||||
- 如果我们要在添加文章时写日志，现在的设计能优雅实现吗？ |
|
||||
|
|
||||
### 预告解决方案（W10） |
|
||||
|
|
||||
- **策略模式** + **仓库层（ArticleRepository）** |
|
||||
- 封装 `List`，对外只暴露 `add()`、`getAll()` 等安全接口 |
|
||||
|
|
||||
> W9 搭骨架，W10 装上盔甲 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 8️⃣ 实践任务（现场5分钟） |
|
||||
|
|
||||
### 必做项 |
|
||||
|
|
||||
1. 使用 Maven 模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现 4 个 Command：help / list / crawl / exit |
|
||||
4. `list` 能展示已抓取的文章（目前存根即可） |
|
||||
5. 运行并测试循环 |
|
||||
|
|
||||
### 额外加分：代码找茬 |
|
||||
|
|
||||
- 检查是否仍有 `System.out` 直接调用 |
|
||||
- 检查 ANSI 码是否硬编码在多个地方 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 验收标准 |
|
||||
|
|
||||
- [x] Maven 编译通过 |
|
||||
- [x] Command 接口和 4 个实现在不同文件 |
|
||||
- [x] Controller 里没有 switch-case |
|
||||
- [x] 新增命令只需新建类，不改 Controller |
|
||||
- [x] list 能正确显示空列表 |
|
||||
- [x] 所有输出均通过 `ConsoleView` |
|
||||
- [x] ANSI 颜色码集中定义为常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 9️⃣ 课后作业 |
|
||||
|
|
||||
### 必做 |
|
||||
|
|
||||
1. **完善 Article**：增加 `author`、`publishDate` 字段 |
|
||||
2. **★ HistoryCommand**：记录用户输入过的所有命令（用 `List<String>`） |
|
||||
3. **AI 架构审计**：将类名发给 AI，指令： |
|
||||
> “作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？” |
|
||||
|
|
||||
### 选做 |
|
||||
|
|
||||
- 命令别名（c 代替 crawl） |
|
||||
- URL 格式验证 |
|
||||
- 暗色主题（修改一处常量） |
|
||||
- 思考题：分析 `List<Article>` 共享引用的风险（200字小结） |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤖 AI 协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**步骤**： |
|
||||
1. 列出所有类名（不含方法实现） |
|
||||
2. 发给 AI |
|
||||
3. 指令：“检查 MVC 分层是否清晰，是否有越权行为” |
|
||||
|
|
||||
### 进阶探究（选做） |
|
||||
|
|
||||
> “假设我的 Command 接口中 execute 方法接收了一个 `List<Article>` 参数，请分析这种设计在工程上有什么隐患，并给出重构建议。” |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 📚 总结与过渡 |
|
||||
|
|
||||
### 本周成果 |
|
||||
|
|
||||
- ✅ 工程化包结构 |
|
||||
- ✅ MVC 分层清晰 |
|
||||
- ✅ Command 模式实现可扩展路由 |
|
||||
- ✅ 所有输出走 View，常量集中管理 |
|
||||
|
|
||||
### 下周预告 |
|
||||
|
|
||||
- **策略模式**：封装爬取算法 |
|
||||
- **仓库层（Repository）**：武装 `List<Article>`，解决共享隐患 |
|
||||
|
|
||||
> 🚀 从“写代码”到“造系统”，踏出坚实第一步！ |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Q&A |
|
||||
|
|
||||
### 常见问题 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA 不识别 pom.xml | 右键 → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → File Encodings → UTF-8 | |
|
||||
| 输出颜色乱码 | Windows 建议使用 Windows Terminal | |
|
||||
| 我的 System.out 被批评 | View 才是唯一输出出口 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 谢谢！ |
|
||||
|
|
||||
### 课件已上传，模板在课程群 |
|
||||
|
|
||||
**保持工程洁癖，下周见！** |
|
||||
@ -1,4 +0,0 @@ |
|||||
*.jar |
|
||||
*.jar |
|
||||
*.class |
|
||||
*.log |
|
||||
@ -1,17 +0,0 @@ |
|||||
# DataCollect 教学项目 — 最小可运行版本 |
|
||||
|
|
||||
这是一个最小可用的 Java CLI 演示工程，目标：打印帮助信息以验证运行环境。 |
|
||||
|
|
||||
构建： |
|
||||
```bash |
|
||||
mvn -q package |
|
||||
``` |
|
||||
|
|
||||
运行（示例）： |
|
||||
```bash |
|
||||
java -jar target/datacollect-cli-0.1.0-jar-with-dependencies.jar --help |
|
||||
``` |
|
||||
|
|
||||
项目结构（最小）： |
|
||||
- `src/main/java/com/example/datacollect/Main.java` — CLI 入口，打印帮助 |
|
||||
- `pom.xml` — Maven 构建配置，生成可执行 jar |
|
||||
@ -1,45 +0,0 @@ |
|||||
<project xmlns="http://maven.apache.org/POM/4.0.0" |
|
||||
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" |
|
||||
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> |
|
||||
<modelVersion>4.0.0</modelVersion> |
|
||||
<groupId>com.example</groupId> |
|
||||
<artifactId>datacollect-cli</artifactId> |
|
||||
<version>0.1.0</version> |
|
||||
<properties> |
|
||||
<maven.compiler.source>11</maven.compiler.source> |
|
||||
<maven.compiler.target>11</maven.compiler.target> |
|
||||
</properties> |
|
||||
<build> |
|
||||
<plugins> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-compiler-plugin</artifactId> |
|
||||
<version>3.8.1</version> |
|
||||
</plugin> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-assembly-plugin</artifactId> |
|
||||
<version>3.3.0</version> |
|
||||
<configuration> |
|
||||
<archive> |
|
||||
<manifest> |
|
||||
<mainClass>com.example.datacollect.Main</mainClass> |
|
||||
</manifest> |
|
||||
</archive> |
|
||||
<descriptorRefs> |
|
||||
<descriptorRef>jar-with-dependencies</descriptorRef> |
|
||||
</descriptorRefs> |
|
||||
</configuration> |
|
||||
<executions> |
|
||||
<execution> |
|
||||
<id>make-assembly</id> |
|
||||
<phase>package</phase> |
|
||||
<goals> |
|
||||
<goal>single</goal> |
|
||||
</goals> |
|
||||
</execution> |
|
||||
</executions> |
|
||||
</plugin> |
|
||||
</plugins> |
|
||||
</build> |
|
||||
</project> |
|
||||
@ -1,21 +0,0 @@ |
|||||
package com.example.datacollect; |
|
||||
|
|
||||
import com.example.datacollect.controller.CrawlerController; |
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class Main { |
|
||||
|
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler (w9_1)! Type help for commands."); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,9 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
@ -1,27 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class CrawlCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public CrawlCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "crawl"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
@ -1,24 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ExitCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ExitCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "exit"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
@ -1,28 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class HelpCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HelpCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "help"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands:"); |
|
||||
view.printInfo(" crawl <url> - 爬取指定URL的文章"); |
|
||||
view.printInfo(" list - 列出已爬取的文章"); |
|
||||
view.printInfo(" history - 显示命令历史记录"); |
|
||||
view.printInfo(" help - 显示此帮助信息"); |
|
||||
view.printInfo(" exit - 退出程序"); |
|
||||
} |
|
||||
} |
|
||||
@ -1,45 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class HistoryCommand implements Command { |
|
||||
private static final List<String> commandHistory = new ArrayList<>(); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HistoryCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "history"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (commandHistory.isEmpty()) { |
|
||||
view.printInfo("No command history."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
view.printInfo("Command History:"); |
|
||||
for (int i = 0; i < commandHistory.size(); i++) { |
|
||||
view.printInfo((i + 1) + ". " + commandHistory.get(i)); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
public static void addCommand(String command) { |
|
||||
commandHistory.add(command); |
|
||||
} |
|
||||
|
|
||||
public static List<String> getCommandHistory() { |
|
||||
return new ArrayList<>(commandHistory); |
|
||||
} |
|
||||
|
|
||||
public static void clearHistory() { |
|
||||
commandHistory.clear(); |
|
||||
} |
|
||||
} |
|
||||
@ -1,23 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ListCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ListCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "list"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
@ -1,52 +0,0 @@ |
|||||
package com.example.datacollect.controller; |
|
||||
|
|
||||
import com.example.datacollect.command.Command; |
|
||||
import com.example.datacollect.command.CrawlCommand; |
|
||||
import com.example.datacollect.command.ExitCommand; |
|
||||
import com.example.datacollect.command.HelpCommand; |
|
||||
import com.example.datacollect.command.HistoryCommand; |
|
||||
import com.example.datacollect.command.ListCommand; |
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private final Map<String, Command> commands = new HashMap<>(); |
|
||||
private final ConsoleView view; |
|
||||
private final List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
register(new HelpCommand(view)); |
|
||||
register(new ListCommand(view)); |
|
||||
register(new CrawlCommand(view)); |
|
||||
register(new ExitCommand(view)); |
|
||||
register(new HistoryCommand(view)); |
|
||||
} |
|
||||
|
|
||||
private void register(Command command) { |
|
||||
commands.put(command.getName(), command); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
String text = input == null ? "" : input.trim(); |
|
||||
if (text.isEmpty()) { |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 记录命令历史
|
|
||||
HistoryCommand.addCommand(text); |
|
||||
|
|
||||
String[] args = text.split("\\s+"); |
|
||||
String cmdName = args[0].toLowerCase(); |
|
||||
Command command = commands.get(cmdName); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmdName); |
|
||||
return; |
|
||||
} |
|
||||
command.execute(args, articles); |
|
||||
} |
|
||||
} |
|
||||
@ -1,75 +0,0 @@ |
|||||
package com.example.datacollect.model; |
|
||||
|
|
||||
import java.time.LocalDate; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
private String author; |
|
||||
private LocalDate publishDate; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public Article(String title, String url, String content, String author, LocalDate publishDate) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
this.author = author; |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { |
|
||||
return title; |
|
||||
} |
|
||||
|
|
||||
public void setTitle(String title) { |
|
||||
this.title = title; |
|
||||
} |
|
||||
|
|
||||
public String getUrl() { |
|
||||
return url; |
|
||||
} |
|
||||
|
|
||||
public void setUrl(String url) { |
|
||||
this.url = url; |
|
||||
} |
|
||||
|
|
||||
public String getContent() { |
|
||||
return content; |
|
||||
} |
|
||||
|
|
||||
public void setContent(String content) { |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getAuthor() { |
|
||||
return author; |
|
||||
} |
|
||||
|
|
||||
public void setAuthor(String author) { |
|
||||
this.author = author; |
|
||||
} |
|
||||
|
|
||||
public LocalDate getPublishDate() { |
|
||||
return publishDate; |
|
||||
} |
|
||||
|
|
||||
public void setPublishDate(LocalDate publishDate) { |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{" |
|
||||
+ "title='" + title + '\'' |
|
||||
+ ", url='" + url + '\'' |
|
||||
+ ", author='" + author + '\'' |
|
||||
+ ", publishDate=" + publishDate |
|
||||
+ '}'; |
|
||||
} |
|
||||
} |
|
||||
@ -1,42 +0,0 @@ |
|||||
package com.example.datacollect.view; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_RESET = "\u001B[0m"; |
|
||||
private static final String ANSI_GREEN = "\u001B[32m"; |
|
||||
private static final String ANSI_RED = "\u001B[31m"; |
|
||||
private static final String ANSI_BLUE = "\u001B[34m"; |
|
||||
|
|
||||
private final Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("> "); |
|
||||
return scanner.nextLine(); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
System.out.println(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
System.out.println(ANSI_BLUE + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("暂无文章，请先执行 crawl。"); |
|
||||
return; |
|
||||
} |
|
||||
for (int i = 0; i < articles.size(); i++) { |
|
||||
Article a = articles.get(i); |
|
||||
System.out.println((i + 1) + ". " + a.getTitle() + " | " + a.getUrl()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,758 +0,0 @@ |
|||||
--- |
|
||||
|
|
||||
# 教案：《高级程序设计》第9周——工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
| 项目 | 内容 | |
|
||||
|------|------| |
|
||||
| **课程名称** | 高级程序设计 | |
|
||||
| **周次** | 第9周 | |
|
||||
| **主题** | 工程架构——从"写代码"到"造系统" | |
|
||||
| **学时** | 2学时（90分钟） | |
|
||||
| **授课对象** | 具备Python基础、已完成Java面向对象特性学习的学生 | |
|
||||
| **教学环境** | JDK 17+、IntelliJ IDEA、Maven（模板） | |
|
||||
| **前情提要** | 本课程原计划使用JavaFX GUI，后根据教学反馈转向CLI + MVC + 爬虫工程化 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 教学调整说明：为什么选择CLI而不是GUI？ |
|
||||
|
|
||||
> **原计划**：JavaFX桌面应用 → **新计划**：CLI命令行应用 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **学生痛点** | "窗口点击"与后端能力无关 | 真正锻炼工程思维 | |
|
||||
| **AI辅助** | AI生成FXML，学生看不懂 | AI辅助重构架构 | |
|
||||
| **工程化** | 脱离真实后端开发场景 | 模拟真实服务器/大数据开发 | |
|
||||
| **核心转型** | "视觉装饰"优先 | "逻辑架构"优先 | |
|
||||
|
|
||||
**决策理由**： |
|
||||
1. **985学生需要的是工程思维**，不是拖控件 |
|
||||
2. **接口抽象**是弱项，CLI + MVC更能暴露这个问题 |
|
||||
3. **彩色终端**足够酷炫，且代码量可控 |
|
||||
|
|
||||
**更深层的教育价值**： |
|
||||
> 在GUI框架中，架构已被框架强制划定，学生只是"遵守规矩"；而CLI世界里没有任何框架告诉你模型在哪、视图在哪——**当外部约束消失，内部的工程纪律才真正建立**。这正是本节课要传递的核心精神。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 一、教学目标 |
|
||||
|
|
||||
| 目标维度 | 具体描述 | |
|
||||
|----------|----------| |
|
||||
| **知识掌握** | 理解MVC架构的职责划分及其演化脉络；掌握Maven项目结构与pom.xml基础；理解Command模式的路由原理。 | |
|
||||
| **工程实践** | 能搭建规范的Maven项目包结构；能实现基于Scanner的控制台交互；能用Command接口实现可扩展的命令路由；能识别架构中的"越权行为"。 | |
|
||||
| **思维转型** | 从"一个类写全部"转向"分层解耦"；从"修改现有代码"转向"新增类实现功能"；从"满足功能"转向"代码的工程洁癖"。 | |
|
||||
| **工具应用** | 利用AI辅助审查MVC职责越权；让AI扮演"架构审计师"检查分层是否清晰；理解AI生成代码中的架构缺陷。 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 二、教学重点与难点 |
|
||||
|
|
||||
| 项目 | 内容 | 突破方法 | |
|
||||
|------|------|----------| |
|
||||
| **重点** | MVC三层职责划分、CLI交互实现、Command接口解耦、代码中的工程细节（常量、输出归属） | 以"新增命令需要改什么"为切入点，展示Command模式的优势；通过现场"代码找茬"强化细节意识 | |
|
||||
| **难点** | Controller不写业务逻辑、Command接口的多态实现、共享数据模型的设计缺陷识别 | 现场演示：增加一个命令只需新建类，无需修改Controller；暴露`List<Article>`共享引用的问题并预告解决方案 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三、教学过程设计（90分钟） |
|
||||
|
|
||||
| 环节 | 时间 | 教学内容 | 师生活动 | AI协同点 | |
|
||||
|------|------|----------|----------|----------| |
|
||||
| **1. 痛点引入：从脚本到工程的鸿沟** | 10' | 展示"意大利面"式爬虫代码，演示改一处需要动全身 | **教师演示**：现场展示一段混乱代码，让学生找问题 | 用AI分析代码耦合度 | |
|
||||
| **2. CLI vs GUI：架构选择的思考** | 10' | 对比两种方案的优缺点，解释为什么CLI更适合培养工程思维 | **教师讲解**：用对比表格说明选择CLI的理由 | — | |
|
||||
| **3. MVC分层设计** | 20' | 讲解Model/View/Controller三层职责，用"餐厅类比"强化理解，随后批判类比局限性 | **教师讲解**：配合架构图讲解三层交互，引导学生寻找类比破绽 | 用AI生成MVC职责对照表 | |
|
||||
| **4. Command模式：可扩展的命令路由** | 15' | 引入Command接口，解释"一个命令就是一个类" | **类比**：Command像酒店的服务部门，Controller是前台 | 让AI解释Command模式的多态原理 | |
|
||||
| **5. Maven模板与环境** | 5' | 直接使用提供的Maven模板，讲解目录结构 | **教师演示**：解压模板 → IDEA打开 → 运行 | — | |
|
||||
| **6. 三层代码落地** | 20' | **Model**：Article实体<br>**View**：ConsoleView（ANSI常量）<br>**Command接口**+实现<br>**Controller**：Map路由 | **教师演示**：分步写出代码，刻意埋入1~2个"越权细节"让学生找茬 | 学生用AI做"架构审计" | |
|
||||
| **7. 架构反思与展望** | 5' | 指出当前`List<Article>`共享引用的问题，预告W10策略模式与仓库层 | **师生互动**：你发现这个设计有什么风险？ | 让AI分析共享可变状态的危害 | |
|
||||
| **8. 实践任务：空壳程序** | 5' | 搭建完整包结构，实现CLI循环 | 学生现场编码，教师巡视 | 完成后用AI检查包结构 | |
|
||||
| **9. 总结与过渡** | 5' | 本周实现了"骨架+命令可扩展"，下周填入"灵魂"——解析器，并解决数据安全问题 | 总结Command模式优势，预告策略模式 | — | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 四、核心教学内容脚本 |
|
||||
|
|
||||
### 4.1 痛点引入：从脚本到工程的鸿沟（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "同学们，前8周我们学的是Java语法，从变量到类，从继承到接口。但有一个问题：代码写完之后，怎么组织？" |
|
||||
> |
|
||||
> "来看这段代码——这是某个同学写的'爬虫'，他一个人完成了一个'完整'的项目。" |
|
||||
|
|
||||
**展示"脚本式"代码**： |
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
|
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问引导**： |
|
||||
1. "如果我想把标题保存到文件，要改哪里？" |
|
||||
2. "如果我想支持另一个网站，它的HTML结构不一样，要怎么办？" |
|
||||
3. "如果我想让输出变成彩色，要改哪里？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "看到了吗？才60行代码，已经'牵一发而动全身'了。这就是一个'脚本'的宿命——功能全混在一起，改一个小需求，整个文件都要翻。" |
|
||||
> |
|
||||
> "这周我们要解决：**怎么让代码'改起来不疼'？**" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.2 CLI vs GUI：架构选择的思考（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "既然要写一个'完整'的爬虫应用，我们有两个选择：图形界面（GUI）或命令行界面（CLI）。为什么我推荐CLI而不是GUI？" |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **代码量** | FXML + Controller + CSS，大量模板代码 | 纯Java，代码量可控 | |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **后端能力** | 几乎无关 | 模拟真实服务器开发 | |
|
||||
| **可测试性** | 难（需要UI测试框架） | 易（直接测试Command类） | |
|
||||
| **工程思维** | 弱（关注视觉） | 强（关注逻辑） | |
|
||||
|
|
||||
**核心观点**： |
|
||||
> **CLI更需要MVC！** GUI有现成的事件系统（点击按钮→触发事件），而CLI只有字符流。**没有架构，分分钟写成脚本**。MVC在CLI里是"刚需"，不是"装饰"。 |
|
||||
> |
|
||||
> **更深一层**：在GUI里，框架已经硬塞给你一套架构，你只是在填空；但在CLI里，所有结构都必须由你亲手搭建。**当外部约束消失，内部的工程纪律才真正开始建立**——这才是本节课的真正目的。 |
|
||||
|
|
||||
**CLI也能很酷**： |
|
||||
- ANSI彩色输出（红/绿/黄/蓝） |
|
||||
- 表格展示数据 |
|
||||
- 进度条动画 |
|
||||
- 模拟真实大数据开发场景 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.3 MVC分层设计（20分钟） |
|
||||
|
|
||||
#### 4.3.1 MVC的起源与演进 |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "MVC不是新东西，它是1970年代为桌面应用设计的架构思想。但它的核心——'职责分离'——在任何软件里都适用。" |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
#### 4.3.2 从GUI到CLI的映射 |
|
||||
|
|
||||
| GUI组件 | CLI对应 | 说明 | |
|
||||
|--------|--------|------| |
|
||||
| 窗口/按钮 | 命令行输入 | **View = 用户交互** | |
|
||||
| 数据模型 | Article实体类 | **Model = 数据结构** | |
|
||||
| 事件监听 | Command路由 | **Controller = 调度** | |
|
||||
|
|
||||
#### 4.3.3 MVC三层职责 |
|
||||
|
|
||||
**架构图示**： |
|
||||
|
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
│ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ - 接收命令（crawl, help, exit） │ |
|
||||
│ - 分发给对应的Command │ |
|
||||
│ 【口诀】：Controller不管"怎么做"， │ |
|
||||
│ 只管"派给谁" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
│ │ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ - 数据实体 │ │ - 输入解析 │ |
|
||||
│ - 业务逻辑 │ │ - 输出格式化 │ |
|
||||
│ 【口诀】： │ │ 【口诀】： │ |
|
||||
│ Model管"数据" │ │ View管"呈现" │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
**三层职责详解** |
|
||||
|
|
||||
| 层级 | 职责 | 典型代码 | 禁止做什么 | |
|
||||
|------|------|----------|------------| |
|
||||
| **Model** | 数据结构 + 业务逻辑 | `class Article { String title; String content; }` | 不能有`System.out.println`，不能有`Scanner` | |
|
||||
| **View** | 接收用户输入 + 格式化输出 | `class ConsoleView { String readInput(); void print(String); }` | 不能写爬虫逻辑，只做"传声筒" | |
|
||||
| **Controller** | 协调调度 | `class CrawlerController { void handle(String cmd) { ... } }` | 不能直接写业务细节，委托给Command | |
|
||||
|
|
||||
#### 4.3.4 类比强化："餐厅类比" |
|
||||
|
|
||||
> "把MVC想象成一家餐厅： |
|
||||
> - **Model是后厨**：只管做菜（数据加工），不管谁来吃、怎么端 |
|
||||
> - **View是服务员**：只管端菜和收钱（输入输出），不管菜怎么做 |
|
||||
> - **Controller是前台**：只管把顾客的点单传给后厨，把做好的菜端给顾客 |
|
||||
> |
|
||||
> 如果后厨开始管'谁来吃饭'，这餐厅就乱了。" |
|
||||
|
|
||||
#### 4.3.5 对"餐厅类比"的批判性思考（关键！） |
|
||||
|
|
||||
**教师导引**： |
|
||||
> "刚才的类比好理解吗？很好。但任何一个类比都有它的边界，如果把它当成真理，就会出问题。现在我们来给这个类比'找茬'。" |
|
||||
|
|
||||
**提问学生**： |
|
||||
1. "后厨真的完全不知道客人是谁吗？如果客人有忌口（比如不吃香菜），这个信息需不需要传到后厨？" |
|
||||
2. "服务员只是端菜吗？在真实餐厅里，服务员经常向后厨反馈'客人觉得今天的菜咸了'，这属于View→Model的反向影响吗？" |
|
||||
3. "在这个类比里，我们把前台（Controller）和后厨（Model）的关系说成单向的。但实际上，后厨做完了菜，需要通知前台'菜好了'，这不就是**观察者模式**吗？" |
|
||||
|
|
||||
**点明本质**： |
|
||||
> "实际MVC的数据流向常常是**双向**的：Controller调用Model的方法改变数据，Model变化后又通知View更新显示。只不过在本次CLI项目中，我们暂时使用'请求-响应'的单向简化模型——用户输入命令，系统处理，然后立即输出结果。这个简化版够用，但你要知道完整的MVC是更动态的。随着系统复杂，Model层需要一个专门的'仓库类'来管理数据，并通知视图刷新——这正是W10我们将要深入的内容。" |
|
||||
|
|
||||
#### 4.3.6 MVC的数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，目前暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.4 Command模式：可扩展的命令路由（15分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在引入一个设计模式——Command（命令）模式。它的核心思想是：**一个命令就是一个类**。" |
|
||||
|
|
||||
#### 4.4.1 为什么需要Command模式？ |
|
||||
|
|
||||
**演示：增加一个命令的代价（switch-case版）** |
|
||||
```java |
|
||||
// 现状代码 |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果我想增加10个命令，这个类要改多少次？" |
|
||||
- "如果我不小心删了一个case，整个程序还能跑吗？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "每加一个功能，就要在这个类里戳一个洞。**这就是'肥控制器'陷阱**——所有的逻辑都堆在Controller里，它变成了新的'意大利面'。" |
|
||||
|
|
||||
#### 4.4.2 Command模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| **Command接口** | 抽象的"订单" | `Command` 接口 | |
|
||||
| **ConcreteCommand** | 具体的订单 | `HelpCommand`、`CrawlCommand` | |
|
||||
| **Invoker** | 接单的前台 | `CrawlerController` | |
|
||||
| **Receiver** | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
#### 4.4.3 Command接口定义 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/command/Command.java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); // 命令名，如 "crawl" |
|
||||
void execute(String[] args, List<Article> articles); // 执行逻辑 |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.4.4 Controller的变革（从switch到Map） |
|
||||
|
|
||||
```java |
|
||||
// 修改后的Controller |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands; // 用Map存命令 |
|
||||
private ConsoleView view; // 持有View以输出错误 |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.commands = new HashMap<>(); |
|
||||
// 增加命令无需改Controller代码，只需在这里注册 |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmd = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command command = commands.get(cmd); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmd); // 通过View输出，而非直接System.out |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 执行命令，传入参数和文章列表 |
|
||||
command.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | execute()的多态调用 | |
|
||||
| 可测试性 | 难 | 每个Command可单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
**类比强化**： |
|
||||
> "Command模式就像**酒店的客房服务**：每个服务（清理、送餐、按摩）都是一个独立的部门。前台（Controller）只负责接电话，然后把请求'派发'给对应的部门。部门自己知道怎么干活，不需要前台教。" |
|
||||
> |
|
||||
> "如果想新增一个服务，前台只需要'登记'一下，不需要把现有部门重新装修。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.5 Maven模板与环境（5分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "这周我们不发愁pom.xml配置。我已经把 Maven 模板准备好了，你们只需要解压、打开、运行。" |
|
||||
|
|
||||
**模板使用流程**： |
|
||||
``` |
|
||||
1. 解压 [my-crawler-template.zip] |
|
||||
2. 用 IDEA 打开文件夹 |
|
||||
3. 右键 pom.xml → Maven → Reload Project |
|
||||
4. 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
**标准目录结构**： |
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/ |
|
||||
│ └── Article.java |
|
||||
├── view/ |
|
||||
│ └── ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java (接口) |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/ |
|
||||
└── CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.6 代码落地（20分钟） |
|
||||
|
|
||||
#### 4.6.1 Model层：Article实体 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/model/Article.java |
|
||||
package com.crawler.model; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { return title; } |
|
||||
public void setTitle(String title) { this.title = title; } |
|
||||
public String getUrl() { return url; } |
|
||||
public void setUrl(String url) { this.url = url; } |
|
||||
public String getContent() { return content; } |
|
||||
public void setContent(String content) { this.content = content; } |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{title='" + title + "', url='" + url + "'}"; |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.2 View层：ANSI常量集中管理（工程细节！） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/view/ConsoleView.java |
|
||||
package com.crawler.view; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
// ANSI颜色常量——集中管理，避免散落各处 |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
private static final String ANSI_CYAN = "\033[36m"; |
|
||||
private static final String ANSI_RESET = "\033[0m"; |
|
||||
|
|
||||
private Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("crawler> "); |
|
||||
return scanner.nextLine().trim(); |
|
||||
} |
|
||||
|
|
||||
public void print(String msg) { |
|
||||
System.out.println(msg); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
print(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
print(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
print(ANSI_CYAN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
// 展示文章列表 |
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("No articles yet. Use 'crawl <url>' first."); |
|
||||
return; |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
print("| Title | URL |"); |
|
||||
print("+----------+--------------------------------+"); |
|
||||
for (Article a : articles) { |
|
||||
String title = a.getTitle(); |
|
||||
if (title.length() > 10) title = title.substring(0, 10) + ".."; |
|
||||
String url = a.getUrl(); |
|
||||
if (url.length() > 30) url = url.substring(0, 27) + "..."; |
|
||||
print("| " + String.format("%-10s", title) + " | " + url + " |"); |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
printInfo("Total: " + articles.size() + " articles"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**教师提示**： |
|
||||
> "注意：所有ANSI转义码都被定义为`private static final`常量。如果把`\033[32m`散落在项目各处，一旦想调整颜色，就得满世界去改——这正是我们之前痛批的'意大利面'。**这就是工程细节**。" |
|
||||
|
|
||||
#### 4.6.3 Command接口与四个实现（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// Command.java |
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
|
|
||||
// HelpCommand.java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ListCommand.java |
|
||||
public class ListCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ListCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "list"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// CrawlCommand.java (存根) |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ExitCommand.java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); // 全部输出都通过View，绝不让System.out直接出现在这里 |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**故意埋设的"找茬点"**： |
|
||||
> "我在刚才的代码里有没有隐藏违反MVC原则的地方？`CrawlCommand`的存根里，`view.printInfo("Stub: Would crawl " + args[1]);` —— 这个字符串拼接算是"业务逻辑"吗？留给大家用AI架构审计时讨论。 |
|
||||
|
|
||||
#### 4.6.4 Controller：Map路由（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/controller/CrawlerController.java |
|
||||
package com.crawler.controller; |
|
||||
|
|
||||
import com.crawler.command.*; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
private ConsoleView view; // 持有View |
|
||||
private List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmdName = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command cmd = commands.get(cmdName); |
|
||||
if (cmd == null) { |
|
||||
view.printError("Unknown command: " + cmdName); // 错误信息也走View！ |
|
||||
return; |
|
||||
} |
|
||||
cmd.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.5 main方法：组装 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/App.java |
|
||||
package com.crawler; |
|
||||
|
|
||||
import com.crawler.controller.CrawlerController; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class App { |
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
view.printInfo("Type 'help' for commands."); |
|
||||
|
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.6 架构反思与展望：共享List<Article>的隐患（关键！） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在这个架构已经可用了。但请大家审视一下：我们所有的Command都直接拿到了`List<Article>`的引用。换句话说，任何一个命令都可以随意增、删、改这个列表。" |
|
||||
> |
|
||||
> "这就好像一家酒店，所有服务员、厨师、清洁工都能随意进出保险箱——**数据结构完全裸奔了**。" |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果CrawlCommand不小心写错了代码，把一个null塞进articles，HelpCommand会不会受影响？" |
|
||||
- "如果未来我们要在添加文章时也写入日志文件，现在的设计能优雅实现吗？还是得在所有Command里分别加日志代码？" |
|
||||
|
|
||||
**预告解决方案**： |
|
||||
> "下周，我们将引入**策略模式**和一个真正的**Model仓库层（ArticleRepository）**。这个仓库会把`List`封装起来，对外只提供`add()`、`getAll()`等安全接口。任何命令想修改数据，都必须通过仓库。这就是从'数据结构'到'模型层'的进化——我们W9先搭骨架，W10给它装上盔甲。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.7 实践任务（5分钟） |
|
||||
|
|
||||
**任务要求**： |
|
||||
1. 使用Maven模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现4个Command：help/list/crawl/exit |
|
||||
4. `list`命令能展示已抓取的文章 |
|
||||
5. 运行并测试循环 |
|
||||
6. **代码找茬（额外加分）**：找出你自己代码中是否存在`System.out`直接调用、硬编码ANSI字符串等"越权行为" |
|
||||
|
|
||||
**验收标准**： |
|
||||
- [x] Maven编译通过 |
|
||||
- [x] Command接口和4个实现分离在不同文件 |
|
||||
- [x] Controller里没有switch-case |
|
||||
- [x] 新增命令只需新建类，不改Controller |
|
||||
- [x] list命令能正确显示空列表 |
|
||||
- [x] 所有输出均通过ConsoleView完成，无直接System.out.println（main除外） |
|
||||
- [x] ANSI颜色码集中定义为View常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 五、课后作业 |
|
||||
|
|
||||
### 5.1 必做任务 |
|
||||
|
|
||||
1. **完善Article**：增加`author`、`publishDate`字段 |
|
||||
2. **★ HistoryCommand（强制作业）**： |
|
||||
- 实现`history`命令，记录用户输入过的所有命令 |
|
||||
- 使用`List<String>`存储历史（复习W8集合） |
|
||||
- 示例输出： |
|
||||
``` |
|
||||
crawler> history |
|
||||
1. help |
|
||||
2. list |
|
||||
3. crawl https://example.com |
|
||||
``` |
|
||||
3. **AI架构审计**：将类名和方法名发给AI，指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？Model层是否包含输入输出代码？View层是否越权写了业务逻辑？有没有地方直接使用了System.out或硬编码ANSI码？" |
|
||||
|
|
||||
### 5.2 选做任务 |
|
||||
|
|
||||
1. **命令别名**：给`crawl`增加别名`c`，`help`增加别名`h` |
|
||||
2. **URL验证**：检查URL格式是否以http://或https://开头 |
|
||||
3. **暗色主题**：实现不同的配色方案（利用View中的ANSI常量，只需修改一处即可） |
|
||||
4. **思考并回答**：分析`List<Article>`共享引用的潜在风险，写一段200字的小结 |
|
||||
|
|
||||
### 5.3 思考题 |
|
||||
|
|
||||
1. **Command vs switch-case**：增加10个命令，哪种方式代码改动量更小？ |
|
||||
2. **如果不用Command接口，直接用Map存命令类行不行？** 接口的意义是什么？ |
|
||||
3. **Controller里的`commands.put()`能否减少？** 提示：思考"注册机制" |
|
||||
4. **为什么ExitCommand里的`view.printSuccess("Bye!")`比直接`System.out.println`更"MVC"？** 提示：回忆View的职责 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 六、AI协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**学生执行步骤**： |
|
||||
1. 列出项目中所有类名（不含方法实现） |
|
||||
2. 将类名列表发给AI |
|
||||
3. 输入指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否清晰。Model层是否包含了不应该有的代码（Scanner/System.out）？View层是否越权写了业务逻辑？请指出任何一处直接使用System.out.println的地方，并建议如何改正。" |
|
||||
|
|
||||
**预期AI输出**： |
|
||||
- 指出哪一层有越权行为 |
|
||||
- 建议如何整改 |
|
||||
- 评价整体架构健康度 |
|
||||
|
|
||||
### 进阶AI探究（选做） |
|
||||
|
|
||||
> "假设我的Command接口中execute方法接收了一个`List<Article>`参数，请分析这种设计在工程上有什么隐患，并给出重构建议。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 七、教学反思与调整记录 |
|
||||
|
|
||||
| 日期 | 事项 | 调整内容 | |
|
||||
|------|------|----------| |
|
||||
| 2026-04-28 | 首次编写 | 基于CLI+MVC重构 | |
|
||||
| 2026-04-30 | 教授反馈 | 引入Command模式、提供Maven模板、升级AI协同比 | |
|
||||
| 2026-04-30 | 逻辑重排 | 按"问题→选择→架构→模式"顺序重写 | |
|
||||
| 2026-05-01 | v2 vs V3合并 | 融合深度改进：增加教育哲学、批判性思考、ANSI常量、共享List隐患、故意埋坑 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 附录1：Maven模板说明 |
|
||||
|
|
||||
> 老师提供`my-crawler-template.zip`压缩包，包含： |
|
||||
> - pom.xml（含Jsoup依赖） |
|
||||
> - 空的src/main/java结构 |
|
||||
> - .gitignore |
|
||||
|
|
||||
## 附录2：常见问题速查 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA不识别pom.xml | 右键 pom.xml → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → Editor → File Encodings → UTF-8 | |
|
||||
| 包名大小写 | 包名全小写，类名首字母大写 | |
|
||||
| Command找不到 | 检查是否 implements Command，是否 @Override getName() | |
|
||||
| 命令不生效 | 检查 commands.put() 是否注册了该命令 | |
|
||||
| 输出颜色乱码 | IDEA控制台需支持ANSI，Windows下建议使用Windows Terminal或调整设置 | |
|
||||
| 我的System.out为什么被老师说越权 | View层才是与用户交互的唯一出口，所有输出都应通过View，这样将来改成GUI或日志时只需改View | |
|
||||
|
|
||||
## 附录3：教学逻辑说明 |
|
||||
|
|
||||
| 顺序 | 内容 | 设计理由 | |
|
||||
|------|------|----------| |
|
||||
| 1 | 痛点引入 | 从问题出发，让学生感受"为什么需要架构" | |
|
||||
| 2 | CLI vs GUI | 解释技术选型，建立"工程思维 > 视觉装饰"的认知 | |
|
||||
| 3 | MVC分层 | 核心架构概念，理解职责分离，通过类比及批判加深理解 | |
|
||||
| 4 | Command模式 | 具体实现方式，解决"肥控制器"问题 | |
|
||||
| 5 | Maven | 工具链支持 | |
|
||||
| 6 | 代码落地 | 实践验证，刻意植入细节规范，训练工程洁癖 | |
|
||||
| 7 | 架构反思 | 暴露共享可变状态隐患，为W10策略模式+仓库层做铺垫 | |
|
||||
| 8 | 实践任务 | 现场编码验证 | |
|
||||
| 9 | 总结 | 强化认知，预告下周 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 版本说明 |
|
||||
|
|
||||
- **v1**：首次编写，CLI+MVC基础框架 |
|
||||
- **v2**：按"问题→选择→架构→模式"逻辑重排 |
|
||||
- **v3 (本版)**：融合v2结构 + V3深度改进，包含： |
|
||||
- 更深的CLI教育哲学 |
|
||||
- 餐厅类比批判性思考 |
|
||||
- ANSI常量集中管理工程细节 |
|
||||
- 全部输出走View |
|
||||
- 共享List架构隐患反思 |
|
||||
- 故意埋坑让学生找茬 |
|
||||
- W10铺垫（策略模式+仓库层） |
|
||||
@ -1,5 +0,0 @@ |
|||||
#Generated by Maven |
|
||||
#Thu Apr 30 11:50:54 CST 2026 |
|
||||
artifactId=datacollect-cli |
|
||||
groupId=com.example |
|
||||
version=0.1.0 |
|
||||
@ -1,530 +0,0 @@ |
|||||
## 高级程序设计 · 第9周 |
|
||||
|
|
||||
#### 工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
##### CLI + MVC + Command模式实战 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 📌 本周导航 |
|
||||
|
|
||||
- 痛点引入：脚本的宿命 |
|
||||
- CLI vs GUI：为什么选命令行？ |
|
||||
- MVC分层：职责分离的艺术 |
|
||||
- Command模式：可扩展的路由 |
|
||||
- Maven模板：工程化第一步 |
|
||||
- 代码落地：从接口到实现 |
|
||||
- 架构反思：共享数据的隐患 |
|
||||
- 实践任务 + 课后作业 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 1️⃣ 痛点引入：从脚本到工程的鸿沟 |
|
||||
|
|
||||
#### 这是一段“意大利面”爬虫 |
|
||||
|
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 脚本的三大痛点 |
|
||||
|
|
||||
| 需求 | 需要改哪里？ | |
|
||||
|------|--------------| |
|
||||
| 保存标题到文件 | 改 main 内部逻辑 | |
|
||||
| 支持不同网站结构 | 全部重写解析代码 | |
|
||||
| 彩色输出 | 一个一个改 print | |
|
||||
|
|
||||
> 😫 **牵一发而动全身 → 改起来疼** |
|
||||
|
|
||||
### 本周目标：**让代码“改起来不疼”** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 2️⃣ CLI vs GUI：架构选择的思考 |
|
||||
|
|
||||
### 图形界面 vs 命令行 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| 学习重心 | 布局、控件、事件 | **架构、分层、路由** | |
|
||||
| 后端能力 | 弱 | 模拟真实服务器 | |
|
||||
| 工程思维 | 弱（关注视觉） | **强（关注逻辑）** | |
|
||||
| 可测试性 | 难 | 易 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 核心观点 |
|
||||
|
|
||||
> **CLI 更需要 MVC！** |
|
||||
|
|
||||
- GUI 有现成事件系统，框架强塞给你一套架构 |
|
||||
- CLI 只有字符流 → **没有架构，分分钟写成脚本** |
|
||||
|
|
||||
> 🎯 **当外部约束消失，内部的工程纪律才真正开始建立** |
|
||||
|
|
||||
### CLI 也能很酷 |
|
||||
|
|
||||
- ANSI 彩色输出 |
|
||||
- 表格展示数据 |
|
||||
- 模拟大数据/后端开发 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 3️⃣ MVC 分层设计 |
|
||||
|
|
||||
### MVC 的起源与演进 |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
**核心不变：职责分离** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 三层职责 |
|
||||
|
|
||||
![[mvc.png]] |
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ 只管"派给谁"，不管"怎么做" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ 管"数据" │ │ 管"呈现" │ |
|
||||
│ + 业务逻辑 │ │ + 输入输出 │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三层“禁止做什么” |
|
||||
|
|
||||
| 层级 | 禁止行为 | |
|
||||
| -------------- | -------------------------------------- | |
|
||||
| **Model** | 不能有 `System.out.println`，不能有 `Scanner` | |
|
||||
| **View** | 不能写爬虫逻辑，只做“传声筒” | |
|
||||
| **Controller** | 不能直接写业务细节，委托给 Command | |
|
||||
|
|
||||
> 🔴 **越权就是架构腐败的开始** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🍽️ 餐厅类比（帮助理解） |
|
||||
|
|
||||
- **Model = 后厨**：只管做菜，不管谁来吃、怎么端 |
|
||||
- **View = 服务员**：只管端菜和收钱，不管菜怎么做 |
|
||||
- **Controller = 前台**：接单 → 派给后厨 → 叫服务员上菜 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤔 对类比的批判性思考（关键！） |
|
||||
|
|
||||
> 任何类比都有边界，不要当成真理 |
|
||||
|
|
||||
| 场景 | 暴露的问题 | |
|
||||
|------|------------| |
|
||||
| 客人有忌口（不吃香菜） | 信息需要传到后厨 → Model 可能需要知道 meta 信息 | |
|
||||
| 服务员反馈“今天的菜咸了” | View → Model 反向影响 | |
|
||||
| 后厨做完菜通知前台 | **观察者模式**，数据流可能是双向的 | |
|
||||
|
|
||||
**本课程简化模型**：请求-响应，单向流 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 4️⃣ Command 模式：可扩展的命令路由 |
|
||||
|
|
||||
### 为什么需要 Command 模式？ |
|
||||
|
|
||||
```java |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 每加一个功能，就要在这个类里戳一个洞 → **肥控制器陷阱** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| Command接口 | 抽象的“订单” | `Command` | |
|
||||
| ConcreteCommand | 具体的订单 | `HelpCommand` | |
|
||||
| Invoker | 接单的前台 | `CrawlerController` | |
|
||||
| Receiver | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 接口定义 |
|
||||
|
|
||||
```java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller 的变革：从 switch 到 Map |
|
||||
|
|
||||
```java |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
// 解析命令 → 从 Map 取 Command → 调用 execute |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> **增加新命令：只需新建类，Controller 零改动！** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 对比：switch-case vs Command |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改 Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | `execute()` 多态 | |
|
||||
| 可测试性 | 难 | 每个 Command 单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
> 🏨 **类比：酒店客房服务，前台只负责派单** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 5️⃣ Maven 模板与环境（5分钟） |
|
||||
|
|
||||
### 直接使用模板，不折腾配置 |
|
||||
|
|
||||
``` |
|
||||
my-crawler-template.zip |
|
||||
↓ 解压 + IDEA打开 |
|
||||
↓ 右键 pom.xml → Maven → Reload Project |
|
||||
↓ 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
### 标准目录结构 |
|
||||
|
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/Article.java |
|
||||
├── view/ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 6️⃣ 代码落地（分步实现） |
|
||||
|
|
||||
### Model：Article 实体 |
|
||||
|
|
||||
```java |
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
// 构造器、getter/setter、toString |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 📦 只存放数据，没有任何输入输出代码 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## View：ConsoleView（ANSI常量集中管理） |
|
||||
|
|
||||
```java |
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
// ... 其他常量 |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
public void printError(String msg) { ... } |
|
||||
public void display(List<Article> articles) { ... } |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✨ **所有颜色码集中定义 → 改主题只需改一处** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 实现示例（HelpCommand） |
|
||||
|
|
||||
```java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ⚠️ 全部输出通过 `view`，绝不让 `System.out` 直接出现在这里 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## CrawlCommand（存根，下周填坑） |
|
||||
|
|
||||
```java |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔍 **找茬点**：这里拼接字符串算是“业务逻辑”吗？留给大家用 AI 审计。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## ExitCommand |
|
||||
|
|
||||
```java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✅ 所有输出都通过 View → 将来改 GUI 只需换 View 实现 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller + main 组装 |
|
||||
|
|
||||
```java |
|
||||
// Controller 中持有 Map<String,Command> |
|
||||
// App.java 中： |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔁 完成交互循环 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 7️⃣ 架构反思：共享 List<Article> 的隐患 |
|
||||
|
|
||||
### 当前问题 |
|
||||
|
|
||||
- 所有 Command 都直接拿到 `List<Article>` 引用 |
|
||||
- 任何一个命令都可以随意增、删、改列表 |
|
||||
- 数据完全“裸奔” |
|
||||
|
|
||||
> 🚨 就像酒店所有员工都能进保险箱 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 提问 |
|
||||
|
|
||||
- 如果 `CrawlCommand` 不小心把 `null` 塞进列表，`ListCommand` 会怎样？ |
|
||||
- 如果我们要在添加文章时写日志，现在的设计能优雅实现吗？ |
|
||||
|
|
||||
### 预告解决方案（W10） |
|
||||
|
|
||||
- **策略模式** + **仓库层（ArticleRepository）** |
|
||||
- 封装 `List`，对外只暴露 `add()`、`getAll()` 等安全接口 |
|
||||
|
|
||||
> W9 搭骨架，W10 装上盔甲 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 8️⃣ 实践任务（现场5分钟） |
|
||||
|
|
||||
### 必做项 |
|
||||
|
|
||||
1. 使用 Maven 模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现 4 个 Command：help / list / crawl / exit |
|
||||
4. `list` 能展示已抓取的文章（目前存根即可） |
|
||||
5. 运行并测试循环 |
|
||||
|
|
||||
### 额外加分：代码找茬 |
|
||||
|
|
||||
- 检查是否仍有 `System.out` 直接调用 |
|
||||
- 检查 ANSI 码是否硬编码在多个地方 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 验收标准 |
|
||||
|
|
||||
- [x] Maven 编译通过 |
|
||||
- [x] Command 接口和 4 个实现在不同文件 |
|
||||
- [x] Controller 里没有 switch-case |
|
||||
- [x] 新增命令只需新建类，不改 Controller |
|
||||
- [x] list 能正确显示空列表 |
|
||||
- [x] 所有输出均通过 `ConsoleView` |
|
||||
- [x] ANSI 颜色码集中定义为常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 9️⃣ 课后作业 |
|
||||
|
|
||||
### 必做 |
|
||||
|
|
||||
1. **完善 Article**：增加 `author`、`publishDate` 字段 |
|
||||
2. **★ HistoryCommand**：记录用户输入过的所有命令（用 `List<String>`） |
|
||||
3. **AI 架构审计**：将类名发给 AI，指令： |
|
||||
> “作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？” |
|
||||
|
|
||||
### 选做 |
|
||||
|
|
||||
- 命令别名（c 代替 crawl） |
|
||||
- URL 格式验证 |
|
||||
- 暗色主题（修改一处常量） |
|
||||
- 思考题：分析 `List<Article>` 共享引用的风险（200字小结） |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤖 AI 协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**步骤**： |
|
||||
1. 列出所有类名（不含方法实现） |
|
||||
2. 发给 AI |
|
||||
3. 指令：“检查 MVC 分层是否清晰，是否有越权行为” |
|
||||
|
|
||||
### 进阶探究（选做） |
|
||||
|
|
||||
> “假设我的 Command 接口中 execute 方法接收了一个 `List<Article>` 参数，请分析这种设计在工程上有什么隐患，并给出重构建议。” |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 📚 总结与过渡 |
|
||||
|
|
||||
### 本周成果 |
|
||||
|
|
||||
- ✅ 工程化包结构 |
|
||||
- ✅ MVC 分层清晰 |
|
||||
- ✅ Command 模式实现可扩展路由 |
|
||||
- ✅ 所有输出走 View，常量集中管理 |
|
||||
|
|
||||
### 下周预告 |
|
||||
|
|
||||
- **策略模式**：封装爬取算法 |
|
||||
- **仓库层（Repository）**：武装 `List<Article>`，解决共享隐患 |
|
||||
|
|
||||
> 🚀 从“写代码”到“造系统”，踏出坚实第一步！ |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Q&A |
|
||||
|
|
||||
### 常见问题 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA 不识别 pom.xml | 右键 → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → File Encodings → UTF-8 | |
|
||||
| 输出颜色乱码 | Windows 建议使用 Windows Terminal | |
|
||||
| 我的 System.out 被批评 | View 才是唯一输出出口 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 谢谢！ |
|
||||
|
|
||||
### 课件已上传，模板在课程群 |
|
||||
|
|
||||
**保持工程洁癖，下周见！** |
|
||||
@ -1,4 +0,0 @@ |
|||||
*.jar |
|
||||
*.jar |
|
||||
*.class |
|
||||
*.log |
|
||||
@ -1,17 +0,0 @@ |
|||||
# DataCollect 教学项目 — 最小可运行版本 |
|
||||
|
|
||||
这是一个最小可用的 Java CLI 演示工程，目标：打印帮助信息以验证运行环境。 |
|
||||
|
|
||||
构建： |
|
||||
```bash |
|
||||
mvn -q package |
|
||||
``` |
|
||||
|
|
||||
运行（示例）： |
|
||||
```bash |
|
||||
java -jar target/datacollect-cli-0.1.0-jar-with-dependencies.jar --help |
|
||||
``` |
|
||||
|
|
||||
项目结构（最小）： |
|
||||
- `src/main/java/com/example/datacollect/Main.java` — CLI 入口，打印帮助 |
|
||||
- `pom.xml` — Maven 构建配置，生成可执行 jar |
|
||||
@ -1,45 +0,0 @@ |
|||||
<project xmlns="http://maven.apache.org/POM/4.0.0" |
|
||||
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" |
|
||||
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> |
|
||||
<modelVersion>4.0.0</modelVersion> |
|
||||
<groupId>com.example</groupId> |
|
||||
<artifactId>datacollect-cli</artifactId> |
|
||||
<version>0.1.0</version> |
|
||||
<properties> |
|
||||
<maven.compiler.source>11</maven.compiler.source> |
|
||||
<maven.compiler.target>11</maven.compiler.target> |
|
||||
</properties> |
|
||||
<build> |
|
||||
<plugins> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-compiler-plugin</artifactId> |
|
||||
<version>3.8.1</version> |
|
||||
</plugin> |
|
||||
<plugin> |
|
||||
<groupId>org.apache.maven.plugins</groupId> |
|
||||
<artifactId>maven-assembly-plugin</artifactId> |
|
||||
<version>3.3.0</version> |
|
||||
<configuration> |
|
||||
<archive> |
|
||||
<manifest> |
|
||||
<mainClass>com.example.datacollect.Main</mainClass> |
|
||||
</manifest> |
|
||||
</archive> |
|
||||
<descriptorRefs> |
|
||||
<descriptorRef>jar-with-dependencies</descriptorRef> |
|
||||
</descriptorRefs> |
|
||||
</configuration> |
|
||||
<executions> |
|
||||
<execution> |
|
||||
<id>make-assembly</id> |
|
||||
<phase>package</phase> |
|
||||
<goals> |
|
||||
<goal>single</goal> |
|
||||
</goals> |
|
||||
</execution> |
|
||||
</executions> |
|
||||
</plugin> |
|
||||
</plugins> |
|
||||
</build> |
|
||||
</project> |
|
||||
@ -1,21 +0,0 @@ |
|||||
package com.example.datacollect; |
|
||||
|
|
||||
import com.example.datacollect.controller.CrawlerController; |
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class Main { |
|
||||
|
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler (w9_1)! Type help for commands."); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,9 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
@ -1,27 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class CrawlCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public CrawlCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "crawl"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
@ -1,24 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ExitCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ExitCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "exit"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
@ -1,28 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class HelpCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HelpCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "help"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands:"); |
|
||||
view.printInfo(" crawl <url> - 爬取指定URL的文章"); |
|
||||
view.printInfo(" list - 列出已爬取的文章"); |
|
||||
view.printInfo(" history - 显示命令历史记录"); |
|
||||
view.printInfo(" help - 显示此帮助信息"); |
|
||||
view.printInfo(" exit - 退出程序"); |
|
||||
} |
|
||||
} |
|
||||
@ -1,45 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class HistoryCommand implements Command { |
|
||||
private static final List<String> commandHistory = new ArrayList<>(); |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public HistoryCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "history"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (commandHistory.isEmpty()) { |
|
||||
view.printInfo("No command history."); |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
view.printInfo("Command History:"); |
|
||||
for (int i = 0; i < commandHistory.size(); i++) { |
|
||||
view.printInfo((i + 1) + ". " + commandHistory.get(i)); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
public static void addCommand(String command) { |
|
||||
commandHistory.add(command); |
|
||||
} |
|
||||
|
|
||||
public static List<String> getCommandHistory() { |
|
||||
return new ArrayList<>(commandHistory); |
|
||||
} |
|
||||
|
|
||||
public static void clearHistory() { |
|
||||
commandHistory.clear(); |
|
||||
} |
|
||||
} |
|
||||
@ -1,23 +0,0 @@ |
|||||
package com.example.datacollect.command; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class ListCommand implements Command { |
|
||||
private final ConsoleView view; |
|
||||
|
|
||||
public ListCommand(ConsoleView view) { |
|
||||
this.view = view; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String getName() { |
|
||||
return "list"; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
@ -1,52 +0,0 @@ |
|||||
package com.example.datacollect.controller; |
|
||||
|
|
||||
import com.example.datacollect.command.Command; |
|
||||
import com.example.datacollect.command.CrawlCommand; |
|
||||
import com.example.datacollect.command.ExitCommand; |
|
||||
import com.example.datacollect.command.HelpCommand; |
|
||||
import com.example.datacollect.command.HistoryCommand; |
|
||||
import com.example.datacollect.command.ListCommand; |
|
||||
import com.example.datacollect.model.Article; |
|
||||
import com.example.datacollect.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private final Map<String, Command> commands = new HashMap<>(); |
|
||||
private final ConsoleView view; |
|
||||
private final List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
register(new HelpCommand(view)); |
|
||||
register(new ListCommand(view)); |
|
||||
register(new CrawlCommand(view)); |
|
||||
register(new ExitCommand(view)); |
|
||||
register(new HistoryCommand(view)); |
|
||||
} |
|
||||
|
|
||||
private void register(Command command) { |
|
||||
commands.put(command.getName(), command); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
String text = input == null ? "" : input.trim(); |
|
||||
if (text.isEmpty()) { |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 记录命令历史
|
|
||||
HistoryCommand.addCommand(text); |
|
||||
|
|
||||
String[] args = text.split("\\s+"); |
|
||||
String cmdName = args[0].toLowerCase(); |
|
||||
Command command = commands.get(cmdName); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmdName); |
|
||||
return; |
|
||||
} |
|
||||
command.execute(args, articles); |
|
||||
} |
|
||||
} |
|
||||
@ -1,75 +0,0 @@ |
|||||
package com.example.datacollect.model; |
|
||||
|
|
||||
import java.time.LocalDate; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
private String author; |
|
||||
private LocalDate publishDate; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public Article(String title, String url, String content, String author, LocalDate publishDate) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
this.author = author; |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { |
|
||||
return title; |
|
||||
} |
|
||||
|
|
||||
public void setTitle(String title) { |
|
||||
this.title = title; |
|
||||
} |
|
||||
|
|
||||
public String getUrl() { |
|
||||
return url; |
|
||||
} |
|
||||
|
|
||||
public void setUrl(String url) { |
|
||||
this.url = url; |
|
||||
} |
|
||||
|
|
||||
public String getContent() { |
|
||||
return content; |
|
||||
} |
|
||||
|
|
||||
public void setContent(String content) { |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getAuthor() { |
|
||||
return author; |
|
||||
} |
|
||||
|
|
||||
public void setAuthor(String author) { |
|
||||
this.author = author; |
|
||||
} |
|
||||
|
|
||||
public LocalDate getPublishDate() { |
|
||||
return publishDate; |
|
||||
} |
|
||||
|
|
||||
public void setPublishDate(LocalDate publishDate) { |
|
||||
this.publishDate = publishDate; |
|
||||
} |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{" |
|
||||
+ "title='" + title + '\'' |
|
||||
+ ", url='" + url + '\'' |
|
||||
+ ", author='" + author + '\'' |
|
||||
+ ", publishDate=" + publishDate |
|
||||
+ '}'; |
|
||||
} |
|
||||
} |
|
||||
@ -1,42 +0,0 @@ |
|||||
package com.example.datacollect.view; |
|
||||
|
|
||||
import com.example.datacollect.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_RESET = "\u001B[0m"; |
|
||||
private static final String ANSI_GREEN = "\u001B[32m"; |
|
||||
private static final String ANSI_RED = "\u001B[31m"; |
|
||||
private static final String ANSI_BLUE = "\u001B[34m"; |
|
||||
|
|
||||
private final Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("> "); |
|
||||
return scanner.nextLine(); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
System.out.println(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
System.out.println(ANSI_BLUE + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("暂无文章，请先执行 crawl。"); |
|
||||
return; |
|
||||
} |
|
||||
for (int i = 0; i < articles.size(); i++) { |
|
||||
Article a = articles.get(i); |
|
||||
System.out.println((i + 1) + ". " + a.getTitle() + " | " + a.getUrl()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
@ -1,758 +0,0 @@ |
|||||
--- |
|
||||
|
|
||||
# 教案：《高级程序设计》第9周——工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
| 项目 | 内容 | |
|
||||
|------|------| |
|
||||
| **课程名称** | 高级程序设计 | |
|
||||
| **周次** | 第9周 | |
|
||||
| **主题** | 工程架构——从"写代码"到"造系统" | |
|
||||
| **学时** | 2学时（90分钟） | |
|
||||
| **授课对象** | 具备Python基础、已完成Java面向对象特性学习的学生 | |
|
||||
| **教学环境** | JDK 17+、IntelliJ IDEA、Maven（模板） | |
|
||||
| **前情提要** | 本课程原计划使用JavaFX GUI，后根据教学反馈转向CLI + MVC + 爬虫工程化 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 教学调整说明：为什么选择CLI而不是GUI？ |
|
||||
|
|
||||
> **原计划**：JavaFX桌面应用 → **新计划**：CLI命令行应用 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **学生痛点** | "窗口点击"与后端能力无关 | 真正锻炼工程思维 | |
|
||||
| **AI辅助** | AI生成FXML，学生看不懂 | AI辅助重构架构 | |
|
||||
| **工程化** | 脱离真实后端开发场景 | 模拟真实服务器/大数据开发 | |
|
||||
| **核心转型** | "视觉装饰"优先 | "逻辑架构"优先 | |
|
||||
|
|
||||
**决策理由**： |
|
||||
1. **985学生需要的是工程思维**，不是拖控件 |
|
||||
2. **接口抽象**是弱项，CLI + MVC更能暴露这个问题 |
|
||||
3. **彩色终端**足够酷炫，且代码量可控 |
|
||||
|
|
||||
**更深层的教育价值**： |
|
||||
> 在GUI框架中，架构已被框架强制划定，学生只是"遵守规矩"；而CLI世界里没有任何框架告诉你模型在哪、视图在哪——**当外部约束消失，内部的工程纪律才真正建立**。这正是本节课要传递的核心精神。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 一、教学目标 |
|
||||
|
|
||||
| 目标维度 | 具体描述 | |
|
||||
|----------|----------| |
|
||||
| **知识掌握** | 理解MVC架构的职责划分及其演化脉络；掌握Maven项目结构与pom.xml基础；理解Command模式的路由原理。 | |
|
||||
| **工程实践** | 能搭建规范的Maven项目包结构；能实现基于Scanner的控制台交互；能用Command接口实现可扩展的命令路由；能识别架构中的"越权行为"。 | |
|
||||
| **思维转型** | 从"一个类写全部"转向"分层解耦"；从"修改现有代码"转向"新增类实现功能"；从"满足功能"转向"代码的工程洁癖"。 | |
|
||||
| **工具应用** | 利用AI辅助审查MVC职责越权；让AI扮演"架构审计师"检查分层是否清晰；理解AI生成代码中的架构缺陷。 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 二、教学重点与难点 |
|
||||
|
|
||||
| 项目 | 内容 | 突破方法 | |
|
||||
|------|------|----------| |
|
||||
| **重点** | MVC三层职责划分、CLI交互实现、Command接口解耦、代码中的工程细节（常量、输出归属） | 以"新增命令需要改什么"为切入点，展示Command模式的优势；通过现场"代码找茬"强化细节意识 | |
|
||||
| **难点** | Controller不写业务逻辑、Command接口的多态实现、共享数据模型的设计缺陷识别 | 现场演示：增加一个命令只需新建类，无需修改Controller；暴露`List<Article>`共享引用的问题并预告解决方案 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三、教学过程设计（90分钟） |
|
||||
|
|
||||
| 环节 | 时间 | 教学内容 | 师生活动 | AI协同点 | |
|
||||
|------|------|----------|----------|----------| |
|
||||
| **1. 痛点引入：从脚本到工程的鸿沟** | 10' | 展示"意大利面"式爬虫代码，演示改一处需要动全身 | **教师演示**：现场展示一段混乱代码，让学生找问题 | 用AI分析代码耦合度 | |
|
||||
| **2. CLI vs GUI：架构选择的思考** | 10' | 对比两种方案的优缺点，解释为什么CLI更适合培养工程思维 | **教师讲解**：用对比表格说明选择CLI的理由 | — | |
|
||||
| **3. MVC分层设计** | 20' | 讲解Model/View/Controller三层职责，用"餐厅类比"强化理解，随后批判类比局限性 | **教师讲解**：配合架构图讲解三层交互，引导学生寻找类比破绽 | 用AI生成MVC职责对照表 | |
|
||||
| **4. Command模式：可扩展的命令路由** | 15' | 引入Command接口，解释"一个命令就是一个类" | **类比**：Command像酒店的服务部门，Controller是前台 | 让AI解释Command模式的多态原理 | |
|
||||
| **5. Maven模板与环境** | 5' | 直接使用提供的Maven模板，讲解目录结构 | **教师演示**：解压模板 → IDEA打开 → 运行 | — | |
|
||||
| **6. 三层代码落地** | 20' | **Model**：Article实体<br>**View**：ConsoleView（ANSI常量）<br>**Command接口**+实现<br>**Controller**：Map路由 | **教师演示**：分步写出代码，刻意埋入1~2个"越权细节"让学生找茬 | 学生用AI做"架构审计" | |
|
||||
| **7. 架构反思与展望** | 5' | 指出当前`List<Article>`共享引用的问题，预告W10策略模式与仓库层 | **师生互动**：你发现这个设计有什么风险？ | 让AI分析共享可变状态的危害 | |
|
||||
| **8. 实践任务：空壳程序** | 5' | 搭建完整包结构，实现CLI循环 | 学生现场编码，教师巡视 | 完成后用AI检查包结构 | |
|
||||
| **9. 总结与过渡** | 5' | 本周实现了"骨架+命令可扩展"，下周填入"灵魂"——解析器，并解决数据安全问题 | 总结Command模式优势，预告策略模式 | — | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 四、核心教学内容脚本 |
|
||||
|
|
||||
### 4.1 痛点引入：从脚本到工程的鸿沟（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "同学们，前8周我们学的是Java语法，从变量到类，从继承到接口。但有一个问题：代码写完之后，怎么组织？" |
|
||||
> |
|
||||
> "来看这段代码——这是某个同学写的'爬虫'，他一个人完成了一个'完整'的项目。" |
|
||||
|
|
||||
**展示"脚本式"代码**： |
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
|
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问引导**： |
|
||||
1. "如果我想把标题保存到文件，要改哪里？" |
|
||||
2. "如果我想支持另一个网站，它的HTML结构不一样，要怎么办？" |
|
||||
3. "如果我想让输出变成彩色，要改哪里？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "看到了吗？才60行代码，已经'牵一发而动全身'了。这就是一个'脚本'的宿命——功能全混在一起，改一个小需求，整个文件都要翻。" |
|
||||
> |
|
||||
> "这周我们要解决：**怎么让代码'改起来不疼'？**" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.2 CLI vs GUI：架构选择的思考（10分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "既然要写一个'完整'的爬虫应用，我们有两个选择：图形界面（GUI）或命令行界面（CLI）。为什么我推荐CLI而不是GUI？" |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| **代码量** | FXML + Controller + CSS，大量模板代码 | 纯Java，代码量可控 | |
|
||||
| **学习重心** | 布局、控件、事件监听 | 架构、分层、命令路由 | |
|
||||
| **后端能力** | 几乎无关 | 模拟真实服务器开发 | |
|
||||
| **可测试性** | 难（需要UI测试框架） | 易（直接测试Command类） | |
|
||||
| **工程思维** | 弱（关注视觉） | 强（关注逻辑） | |
|
||||
|
|
||||
**核心观点**： |
|
||||
> **CLI更需要MVC！** GUI有现成的事件系统（点击按钮→触发事件），而CLI只有字符流。**没有架构，分分钟写成脚本**。MVC在CLI里是"刚需"，不是"装饰"。 |
|
||||
> |
|
||||
> **更深一层**：在GUI里，框架已经硬塞给你一套架构，你只是在填空；但在CLI里，所有结构都必须由你亲手搭建。**当外部约束消失，内部的工程纪律才真正开始建立**——这才是本节课的真正目的。 |
|
||||
|
|
||||
**CLI也能很酷**： |
|
||||
- ANSI彩色输出（红/绿/黄/蓝） |
|
||||
- 表格展示数据 |
|
||||
- 进度条动画 |
|
||||
- 模拟真实大数据开发场景 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.3 MVC分层设计（20分钟） |
|
||||
|
|
||||
#### 4.3.1 MVC的起源与演进 |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "MVC不是新东西，它是1970年代为桌面应用设计的架构思想。但它的核心——'职责分离'——在任何软件里都适用。" |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
#### 4.3.2 从GUI到CLI的映射 |
|
||||
|
|
||||
| GUI组件 | CLI对应 | 说明 | |
|
||||
|--------|--------|------| |
|
||||
| 窗口/按钮 | 命令行输入 | **View = 用户交互** | |
|
||||
| 数据模型 | Article实体类 | **Model = 数据结构** | |
|
||||
| 事件监听 | Command路由 | **Controller = 调度** | |
|
||||
|
|
||||
#### 4.3.3 MVC三层职责 |
|
||||
|
|
||||
**架构图示**： |
|
||||
|
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
│ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ - 接收命令（crawl, help, exit） │ |
|
||||
│ - 分发给对应的Command │ |
|
||||
│ 【口诀】：Controller不管"怎么做"， │ |
|
||||
│ 只管"派给谁" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
│ │ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ - 数据实体 │ │ - 输入解析 │ |
|
||||
│ - 业务逻辑 │ │ - 输出格式化 │ |
|
||||
│ 【口诀】： │ │ 【口诀】： │ |
|
||||
│ Model管"数据" │ │ View管"呈现" │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
**三层职责详解** |
|
||||
|
|
||||
| 层级 | 职责 | 典型代码 | 禁止做什么 | |
|
||||
|------|------|----------|------------| |
|
||||
| **Model** | 数据结构 + 业务逻辑 | `class Article { String title; String content; }` | 不能有`System.out.println`，不能有`Scanner` | |
|
||||
| **View** | 接收用户输入 + 格式化输出 | `class ConsoleView { String readInput(); void print(String); }` | 不能写爬虫逻辑，只做"传声筒" | |
|
||||
| **Controller** | 协调调度 | `class CrawlerController { void handle(String cmd) { ... } }` | 不能直接写业务细节，委托给Command | |
|
||||
|
|
||||
#### 4.3.4 类比强化："餐厅类比" |
|
||||
|
|
||||
> "把MVC想象成一家餐厅： |
|
||||
> - **Model是后厨**：只管做菜（数据加工），不管谁来吃、怎么端 |
|
||||
> - **View是服务员**：只管端菜和收钱（输入输出），不管菜怎么做 |
|
||||
> - **Controller是前台**：只管把顾客的点单传给后厨，把做好的菜端给顾客 |
|
||||
> |
|
||||
> 如果后厨开始管'谁来吃饭'，这餐厅就乱了。" |
|
||||
|
|
||||
#### 4.3.5 对"餐厅类比"的批判性思考（关键！） |
|
||||
|
|
||||
**教师导引**： |
|
||||
> "刚才的类比好理解吗？很好。但任何一个类比都有它的边界，如果把它当成真理，就会出问题。现在我们来给这个类比'找茬'。" |
|
||||
|
|
||||
**提问学生**： |
|
||||
1. "后厨真的完全不知道客人是谁吗？如果客人有忌口（比如不吃香菜），这个信息需不需要传到后厨？" |
|
||||
2. "服务员只是端菜吗？在真实餐厅里，服务员经常向后厨反馈'客人觉得今天的菜咸了'，这属于View→Model的反向影响吗？" |
|
||||
3. "在这个类比里，我们把前台（Controller）和后厨（Model）的关系说成单向的。但实际上，后厨做完了菜，需要通知前台'菜好了'，这不就是**观察者模式**吗？" |
|
||||
|
|
||||
**点明本质**： |
|
||||
> "实际MVC的数据流向常常是**双向**的：Controller调用Model的方法改变数据，Model变化后又通知View更新显示。只不过在本次CLI项目中，我们暂时使用'请求-响应'的单向简化模型——用户输入命令，系统处理，然后立即输出结果。这个简化版够用，但你要知道完整的MVC是更动态的。随着系统复杂，Model层需要一个专门的'仓库类'来管理数据，并通知视图刷新——这正是W10我们将要深入的内容。" |
|
||||
|
|
||||
#### 4.3.6 MVC的数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，目前暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.4 Command模式：可扩展的命令路由（15分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在引入一个设计模式——Command（命令）模式。它的核心思想是：**一个命令就是一个类**。" |
|
||||
|
|
||||
#### 4.4.1 为什么需要Command模式？ |
|
||||
|
|
||||
**演示：增加一个命令的代价（switch-case版）** |
|
||||
```java |
|
||||
// 现状代码 |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果我想增加10个命令，这个类要改多少次？" |
|
||||
- "如果我不小心删了一个case，整个程序还能跑吗？" |
|
||||
|
|
||||
**痛点提炼**： |
|
||||
> "每加一个功能，就要在这个类里戳一个洞。**这就是'肥控制器'陷阱**——所有的逻辑都堆在Controller里，它变成了新的'意大利面'。" |
|
||||
|
|
||||
#### 4.4.2 Command模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| **Command接口** | 抽象的"订单" | `Command` 接口 | |
|
||||
| **ConcreteCommand** | 具体的订单 | `HelpCommand`、`CrawlCommand` | |
|
||||
| **Invoker** | 接单的前台 | `CrawlerController` | |
|
||||
| **Receiver** | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
#### 4.4.3 Command接口定义 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/command/Command.java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); // 命令名，如 "crawl" |
|
||||
void execute(String[] args, List<Article> articles); // 执行逻辑 |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.4.4 Controller的变革（从switch到Map） |
|
||||
|
|
||||
```java |
|
||||
// 修改后的Controller |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands; // 用Map存命令 |
|
||||
private ConsoleView view; // 持有View以输出错误 |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.commands = new HashMap<>(); |
|
||||
// 增加命令无需改Controller代码，只需在这里注册 |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmd = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command command = commands.get(cmd); |
|
||||
if (command == null) { |
|
||||
view.printError("Unknown command: " + cmd); // 通过View输出，而非直接System.out |
|
||||
return; |
|
||||
} |
|
||||
|
|
||||
// 执行命令，传入参数和文章列表 |
|
||||
command.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**对比表格** |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | execute()的多态调用 | |
|
||||
| 可测试性 | 难 | 每个Command可单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
**类比强化**： |
|
||||
> "Command模式就像**酒店的客房服务**：每个服务（清理、送餐、按摩）都是一个独立的部门。前台（Controller）只负责接电话，然后把请求'派发'给对应的部门。部门自己知道怎么干活，不需要前台教。" |
|
||||
> |
|
||||
> "如果想新增一个服务，前台只需要'登记'一下，不需要把现有部门重新装修。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.5 Maven模板与环境（5分钟） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "这周我们不发愁pom.xml配置。我已经把 Maven 模板准备好了，你们只需要解压、打开、运行。" |
|
||||
|
|
||||
**模板使用流程**： |
|
||||
``` |
|
||||
1. 解压 [my-crawler-template.zip] |
|
||||
2. 用 IDEA 打开文件夹 |
|
||||
3. 右键 pom.xml → Maven → Reload Project |
|
||||
4. 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
**标准目录结构**： |
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/ |
|
||||
│ └── Article.java |
|
||||
├── view/ |
|
||||
│ └── ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java (接口) |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/ |
|
||||
└── CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.6 代码落地（20分钟） |
|
||||
|
|
||||
#### 4.6.1 Model层：Article实体 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/model/Article.java |
|
||||
package com.crawler.model; |
|
||||
|
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
|
|
||||
public Article(String title, String url, String content) { |
|
||||
this.title = title; |
|
||||
this.url = url; |
|
||||
this.content = content; |
|
||||
} |
|
||||
|
|
||||
public String getTitle() { return title; } |
|
||||
public void setTitle(String title) { this.title = title; } |
|
||||
public String getUrl() { return url; } |
|
||||
public void setUrl(String url) { this.url = url; } |
|
||||
public String getContent() { return content; } |
|
||||
public void setContent(String content) { this.content = content; } |
|
||||
|
|
||||
@Override |
|
||||
public String toString() { |
|
||||
return "Article{title='" + title + "', url='" + url + "'}"; |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.2 View层：ANSI常量集中管理（工程细节！） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/view/ConsoleView.java |
|
||||
package com.crawler.view; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
import java.util.Scanner; |
|
||||
|
|
||||
public class ConsoleView { |
|
||||
// ANSI颜色常量——集中管理，避免散落各处 |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
private static final String ANSI_CYAN = "\033[36m"; |
|
||||
private static final String ANSI_RESET = "\033[0m"; |
|
||||
|
|
||||
private Scanner scanner = new Scanner(System.in); |
|
||||
|
|
||||
public String readLine() { |
|
||||
System.out.print("crawler> "); |
|
||||
return scanner.nextLine().trim(); |
|
||||
} |
|
||||
|
|
||||
public void print(String msg) { |
|
||||
System.out.println(msg); |
|
||||
} |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
print(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printError(String msg) { |
|
||||
print(ANSI_RED + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
public void printInfo(String msg) { |
|
||||
print(ANSI_CYAN + msg + ANSI_RESET); |
|
||||
} |
|
||||
|
|
||||
// 展示文章列表 |
|
||||
public void display(List<Article> articles) { |
|
||||
if (articles.isEmpty()) { |
|
||||
printInfo("No articles yet. Use 'crawl <url>' first."); |
|
||||
return; |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
print("| Title | URL |"); |
|
||||
print("+----------+--------------------------------+"); |
|
||||
for (Article a : articles) { |
|
||||
String title = a.getTitle(); |
|
||||
if (title.length() > 10) title = title.substring(0, 10) + ".."; |
|
||||
String url = a.getUrl(); |
|
||||
if (url.length() > 30) url = url.substring(0, 27) + "..."; |
|
||||
print("| " + String.format("%-10s", title) + " | " + url + " |"); |
|
||||
} |
|
||||
print("+----------+--------------------------------+"); |
|
||||
printInfo("Total: " + articles.size() + " articles"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**教师提示**： |
|
||||
> "注意：所有ANSI转义码都被定义为`private static final`常量。如果把`\033[32m`散落在项目各处，一旦想调整颜色，就得满世界去改——这正是我们之前痛批的'意大利面'。**这就是工程细节**。" |
|
||||
|
|
||||
#### 4.6.3 Command接口与四个实现（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// Command.java |
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
|
|
||||
// HelpCommand.java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ListCommand.java |
|
||||
public class ListCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ListCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "list"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.display(articles); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// CrawlCommand.java (存根) |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
|
|
||||
// ExitCommand.java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); // 全部输出都通过View，绝不让System.out直接出现在这里 |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
**故意埋设的"找茬点"**： |
|
||||
> "我在刚才的代码里有没有隐藏违反MVC原则的地方？`CrawlCommand`的存根里，`view.printInfo("Stub: Would crawl " + args[1]);` —— 这个字符串拼接算是"业务逻辑"吗？留给大家用AI架构审计时讨论。 |
|
||||
|
|
||||
#### 4.6.4 Controller：Map路由（全部通过View输出） |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/controller/CrawlerController.java |
|
||||
package com.crawler.controller; |
|
||||
|
|
||||
import com.crawler.command.*; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.HashMap; |
|
||||
import java.util.List; |
|
||||
import java.util.Map; |
|
||||
|
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
private ConsoleView view; // 持有View |
|
||||
private List<Article> articles; |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
this.view = view; |
|
||||
this.articles = articles; |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
if (input.isEmpty()) return; |
|
||||
String[] parts = input.split("\\s+"); |
|
||||
String cmdName = parts[0].toLowerCase(); |
|
||||
|
|
||||
Command cmd = commands.get(cmdName); |
|
||||
if (cmd == null) { |
|
||||
view.printError("Unknown command: " + cmdName); // 错误信息也走View！ |
|
||||
return; |
|
||||
} |
|
||||
cmd.execute(parts, articles); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.5 main方法：组装 |
|
||||
|
|
||||
```java |
|
||||
// src/main/java/com/crawler/App.java |
|
||||
package com.crawler; |
|
||||
|
|
||||
import com.crawler.controller.CrawlerController; |
|
||||
import com.crawler.model.Article; |
|
||||
import com.crawler.view.ConsoleView; |
|
||||
import java.util.ArrayList; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public class App { |
|
||||
public static void main(String[] args) { |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
|
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
view.printInfo("Type 'help' for commands."); |
|
||||
|
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
#### 4.6.6 架构反思与展望：共享List<Article>的隐患（关键！） |
|
||||
|
|
||||
**教师口播**： |
|
||||
> "现在这个架构已经可用了。但请大家审视一下：我们所有的Command都直接拿到了`List<Article>`的引用。换句话说，任何一个命令都可以随意增、删、改这个列表。" |
|
||||
> |
|
||||
> "这就好像一家酒店，所有服务员、厨师、清洁工都能随意进出保险箱——**数据结构完全裸奔了**。" |
|
||||
|
|
||||
**提问**： |
|
||||
- "如果CrawlCommand不小心写错了代码，把一个null塞进articles，HelpCommand会不会受影响？" |
|
||||
- "如果未来我们要在添加文章时也写入日志文件，现在的设计能优雅实现吗？还是得在所有Command里分别加日志代码？" |
|
||||
|
|
||||
**预告解决方案**： |
|
||||
> "下周，我们将引入**策略模式**和一个真正的**Model仓库层（ArticleRepository）**。这个仓库会把`List`封装起来，对外只提供`add()`、`getAll()`等安全接口。任何命令想修改数据，都必须通过仓库。这就是从'数据结构'到'模型层'的进化——我们W9先搭骨架，W10给它装上盔甲。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 4.7 实践任务（5分钟） |
|
||||
|
|
||||
**任务要求**： |
|
||||
1. 使用Maven模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现4个Command：help/list/crawl/exit |
|
||||
4. `list`命令能展示已抓取的文章 |
|
||||
5. 运行并测试循环 |
|
||||
6. **代码找茬（额外加分）**：找出你自己代码中是否存在`System.out`直接调用、硬编码ANSI字符串等"越权行为" |
|
||||
|
|
||||
**验收标准**： |
|
||||
- [x] Maven编译通过 |
|
||||
- [x] Command接口和4个实现分离在不同文件 |
|
||||
- [x] Controller里没有switch-case |
|
||||
- [x] 新增命令只需新建类，不改Controller |
|
||||
- [x] list命令能正确显示空列表 |
|
||||
- [x] 所有输出均通过ConsoleView完成，无直接System.out.println（main除外） |
|
||||
- [x] ANSI颜色码集中定义为View常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 五、课后作业 |
|
||||
|
|
||||
### 5.1 必做任务 |
|
||||
|
|
||||
1. **完善Article**：增加`author`、`publishDate`字段 |
|
||||
2. **★ HistoryCommand（强制作业）**： |
|
||||
- 实现`history`命令，记录用户输入过的所有命令 |
|
||||
- 使用`List<String>`存储历史（复习W8集合） |
|
||||
- 示例输出： |
|
||||
``` |
|
||||
crawler> history |
|
||||
1. help |
|
||||
2. list |
|
||||
3. crawl https://example.com |
|
||||
``` |
|
||||
3. **AI架构审计**：将类名和方法名发给AI，指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？Model层是否包含输入输出代码？View层是否越权写了业务逻辑？有没有地方直接使用了System.out或硬编码ANSI码？" |
|
||||
|
|
||||
### 5.2 选做任务 |
|
||||
|
|
||||
1. **命令别名**：给`crawl`增加别名`c`，`help`增加别名`h` |
|
||||
2. **URL验证**：检查URL格式是否以http://或https://开头 |
|
||||
3. **暗色主题**：实现不同的配色方案（利用View中的ANSI常量，只需修改一处即可） |
|
||||
4. **思考并回答**：分析`List<Article>`共享引用的潜在风险，写一段200字的小结 |
|
||||
|
|
||||
### 5.3 思考题 |
|
||||
|
|
||||
1. **Command vs switch-case**：增加10个命令，哪种方式代码改动量更小？ |
|
||||
2. **如果不用Command接口，直接用Map存命令类行不行？** 接口的意义是什么？ |
|
||||
3. **Controller里的`commands.put()`能否减少？** 提示：思考"注册机制" |
|
||||
4. **为什么ExitCommand里的`view.printSuccess("Bye!")`比直接`System.out.println`更"MVC"？** 提示：回忆View的职责 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 六、AI协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**学生执行步骤**： |
|
||||
1. 列出项目中所有类名（不含方法实现） |
|
||||
2. 将类名列表发给AI |
|
||||
3. 输入指令： |
|
||||
> "作为Java架构审计师，请检查我的MVC三层划分是否清晰。Model层是否包含了不应该有的代码（Scanner/System.out）？View层是否越权写了业务逻辑？请指出任何一处直接使用System.out.println的地方，并建议如何改正。" |
|
||||
|
|
||||
**预期AI输出**： |
|
||||
- 指出哪一层有越权行为 |
|
||||
- 建议如何整改 |
|
||||
- 评价整体架构健康度 |
|
||||
|
|
||||
### 进阶AI探究（选做） |
|
||||
|
|
||||
> "假设我的Command接口中execute方法接收了一个`List<Article>`参数，请分析这种设计在工程上有什么隐患，并给出重构建议。" |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 七、教学反思与调整记录 |
|
||||
|
|
||||
| 日期 | 事项 | 调整内容 | |
|
||||
|------|------|----------| |
|
||||
| 2026-04-28 | 首次编写 | 基于CLI+MVC重构 | |
|
||||
| 2026-04-30 | 教授反馈 | 引入Command模式、提供Maven模板、升级AI协同比 | |
|
||||
| 2026-04-30 | 逻辑重排 | 按"问题→选择→架构→模式"顺序重写 | |
|
||||
| 2026-05-01 | v2 vs V3合并 | 融合深度改进：增加教育哲学、批判性思考、ANSI常量、共享List隐患、故意埋坑 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 附录1：Maven模板说明 |
|
||||
|
|
||||
> 老师提供`my-crawler-template.zip`压缩包，包含： |
|
||||
> - pom.xml（含Jsoup依赖） |
|
||||
> - 空的src/main/java结构 |
|
||||
> - .gitignore |
|
||||
|
|
||||
## 附录2：常见问题速查 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA不识别pom.xml | 右键 pom.xml → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → Editor → File Encodings → UTF-8 | |
|
||||
| 包名大小写 | 包名全小写，类名首字母大写 | |
|
||||
| Command找不到 | 检查是否 implements Command，是否 @Override getName() | |
|
||||
| 命令不生效 | 检查 commands.put() 是否注册了该命令 | |
|
||||
| 输出颜色乱码 | IDEA控制台需支持ANSI，Windows下建议使用Windows Terminal或调整设置 | |
|
||||
| 我的System.out为什么被老师说越权 | View层才是与用户交互的唯一出口，所有输出都应通过View，这样将来改成GUI或日志时只需改View | |
|
||||
|
|
||||
## 附录3：教学逻辑说明 |
|
||||
|
|
||||
| 顺序 | 内容 | 设计理由 | |
|
||||
|------|------|----------| |
|
||||
| 1 | 痛点引入 | 从问题出发，让学生感受"为什么需要架构" | |
|
||||
| 2 | CLI vs GUI | 解释技术选型，建立"工程思维 > 视觉装饰"的认知 | |
|
||||
| 3 | MVC分层 | 核心架构概念，理解职责分离，通过类比及批判加深理解 | |
|
||||
| 4 | Command模式 | 具体实现方式，解决"肥控制器"问题 | |
|
||||
| 5 | Maven | 工具链支持 | |
|
||||
| 6 | 代码落地 | 实践验证，刻意植入细节规范，训练工程洁癖 | |
|
||||
| 7 | 架构反思 | 暴露共享可变状态隐患，为W10策略模式+仓库层做铺垫 | |
|
||||
| 8 | 实践任务 | 现场编码验证 | |
|
||||
| 9 | 总结 | 强化认知，预告下周 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 版本说明 |
|
||||
|
|
||||
- **v1**：首次编写，CLI+MVC基础框架 |
|
||||
- **v2**：按"问题→选择→架构→模式"逻辑重排 |
|
||||
- **v3 (本版)**：融合v2结构 + V3深度改进，包含： |
|
||||
- 更深的CLI教育哲学 |
|
||||
- 餐厅类比批判性思考 |
|
||||
- ANSI常量集中管理工程细节 |
|
||||
- 全部输出走View |
|
||||
- 共享List架构隐患反思 |
|
||||
- 故意埋坑让学生找茬 |
|
||||
- W10铺垫（策略模式+仓库层） |
|
||||
@ -1,5 +0,0 @@ |
|||||
#Generated by Maven |
|
||||
#Thu Apr 30 11:50:54 CST 2026 |
|
||||
artifactId=datacollect-cli |
|
||||
groupId=com.example |
|
||||
version=0.1.0 |
|
||||
@ -1,530 +0,0 @@ |
|||||
## 高级程序设计 · 第9周 |
|
||||
|
|
||||
#### 工程架构：从"写代码"到"造系统" |
|
||||
|
|
||||
##### CLI + MVC + Command模式实战 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 📌 本周导航 |
|
||||
|
|
||||
- 痛点引入：脚本的宿命 |
|
||||
- CLI vs GUI：为什么选命令行？ |
|
||||
- MVC分层：职责分离的艺术 |
|
||||
- Command模式：可扩展的路由 |
|
||||
- Maven模板：工程化第一步 |
|
||||
- 代码落地：从接口到实现 |
|
||||
- 架构反思：共享数据的隐患 |
|
||||
- 实践任务 + 课后作业 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 1️⃣ 痛点引入：从脚本到工程的鸿沟 |
|
||||
|
|
||||
#### 这是一段“意大利面”爬虫 |
|
||||
|
|
||||
```java |
|
||||
public class Crawler { |
|
||||
public static void main(String[] args) { |
|
||||
System.out.print("请输入URL: "); |
|
||||
Scanner scanner = new Scanner(System.in); |
|
||||
String url = scanner.nextLine(); |
|
||||
List titles = new ArrayList(); |
|
||||
try { |
|
||||
Document doc = Jsoup.connect(url).get(); |
|
||||
Elements elements = doc.select(".post-title"); |
|
||||
for (Element e : elements) { |
|
||||
String title = e.text(); |
|
||||
System.out.println("标题: " + title); |
|
||||
titles.add(title); |
|
||||
} |
|
||||
} catch (Exception ex) { |
|
||||
System.out.println("出错啦: " + ex.getMessage()); |
|
||||
} |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
### 脚本的三大痛点 |
|
||||
|
|
||||
| 需求 | 需要改哪里？ | |
|
||||
|------|--------------| |
|
||||
| 保存标题到文件 | 改 main 内部逻辑 | |
|
||||
| 支持不同网站结构 | 全部重写解析代码 | |
|
||||
| 彩色输出 | 一个一个改 print | |
|
||||
|
|
||||
> 😫 **牵一发而动全身 → 改起来疼** |
|
||||
|
|
||||
### 本周目标：**让代码“改起来不疼”** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 2️⃣ CLI vs GUI：架构选择的思考 |
|
||||
|
|
||||
### 图形界面 vs 命令行 |
|
||||
|
|
||||
| 维度 | GUI (JavaFX) | CLI (命令行) | |
|
||||
|------|--------------|-------------| |
|
||||
| 学习重心 | 布局、控件、事件 | **架构、分层、路由** | |
|
||||
| 后端能力 | 弱 | 模拟真实服务器 | |
|
||||
| 工程思维 | 弱（关注视觉） | **强（关注逻辑）** | |
|
||||
| 可测试性 | 难 | 易 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 核心观点 |
|
||||
|
|
||||
> **CLI 更需要 MVC！** |
|
||||
|
|
||||
- GUI 有现成事件系统，框架强塞给你一套架构 |
|
||||
- CLI 只有字符流 → **没有架构，分分钟写成脚本** |
|
||||
|
|
||||
> 🎯 **当外部约束消失，内部的工程纪律才真正开始建立** |
|
||||
|
|
||||
### CLI 也能很酷 |
|
||||
|
|
||||
- ANSI 彩色输出 |
|
||||
- 表格展示数据 |
|
||||
- 模拟大数据/后端开发 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 3️⃣ MVC 分层设计 |
|
||||
|
|
||||
### MVC 的起源与演进 |
|
||||
|
|
||||
| 年代 | 场景 | MVC的角色 | |
|
||||
|------|------|----------| |
|
||||
| 1970s | Smalltalk-72 GUI | 最早的用户界面架构 | |
|
||||
| 1990s | Web开发 (Struts) | 后端模板引擎 | |
|
||||
| 2000s | ASP.NET MVC | 现代Web框架 | |
|
||||
| 2020s | CLI + API | 解耦业务逻辑与表现层 | |
|
||||
|
|
||||
**核心不变：职责分离** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 三层职责 |
|
||||
|
|
||||
![[mvc.png]] |
|
||||
``` |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ 入口 │ |
|
||||
│ (main方法) │ |
|
||||
└─────────────────┬───────────────────────┘ |
|
||||
▼ |
|
||||
┌─────────────────────────────────────────┐ |
|
||||
│ Controller │ |
|
||||
│ 只管"派给谁"，不管"怎么做" │ |
|
||||
└─────────┬───────────────┬───────────────┘ |
|
||||
▼ ▼ |
|
||||
┌─────────────────┐ ┌─────────────────┐ |
|
||||
│ Model │ │ View │ |
|
||||
│ 管"数据" │ │ 管"呈现" │ |
|
||||
│ + 业务逻辑 │ │ + 输入输出 │ |
|
||||
└─────────────────┘ └─────────────────┘ |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 三层“禁止做什么” |
|
||||
|
|
||||
| 层级 | 禁止行为 | |
|
||||
| -------------- | -------------------------------------- | |
|
||||
| **Model** | 不能有 `System.out.println`，不能有 `Scanner` | |
|
||||
| **View** | 不能写爬虫逻辑，只做“传声筒” | |
|
||||
| **Controller** | 不能直接写业务细节，委托给 Command | |
|
||||
|
|
||||
> 🔴 **越权就是架构腐败的开始** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🍽️ 餐厅类比（帮助理解） |
|
||||
|
|
||||
- **Model = 后厨**：只管做菜，不管谁来吃、怎么端 |
|
||||
- **View = 服务员**：只管端菜和收钱，不管菜怎么做 |
|
||||
- **Controller = 前台**：接单 → 派给后厨 → 叫服务员上菜 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤔 对类比的批判性思考（关键！） |
|
||||
|
|
||||
> 任何类比都有边界，不要当成真理 |
|
||||
|
|
||||
| 场景 | 暴露的问题 | |
|
||||
|------|------------| |
|
||||
| 客人有忌口（不吃香菜） | 信息需要传到后厨 → Model 可能需要知道 meta 信息 | |
|
||||
| 服务员反馈“今天的菜咸了” | View → Model 反向影响 | |
|
||||
| 后厨做完菜通知前台 | **观察者模式**，数据流可能是双向的 | |
|
||||
|
|
||||
**本课程简化模型**：请求-响应，单向流 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## MVC 数据流向（本课程简化版） |
|
||||
|
|
||||
``` |
|
||||
CLI用户输入 |
|
||||
↓ |
|
||||
View（解析命令字符串） |
|
||||
↓ |
|
||||
Controller（找到对应Command） |
|
||||
↓ |
|
||||
Command.execute()（执行业务逻辑） |
|
||||
↓ |
|
||||
Model（Article数据，暂存于List） |
|
||||
↓ |
|
||||
View（display()展示数据） |
|
||||
↓ |
|
||||
CLI终端显示 |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 4️⃣ Command 模式：可扩展的命令路由 |
|
||||
|
|
||||
### 为什么需要 Command 模式？ |
|
||||
|
|
||||
```java |
|
||||
switch (cmd) { |
|
||||
case "crawl": handleCrawl(); break; |
|
||||
case "help": showHelp(); break; |
|
||||
// 如果要增加 list 命令？ |
|
||||
// 1. 加 case "list" |
|
||||
// 2. 加 handleList() 方法 |
|
||||
// 3. 可能还要改其他地方... |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 每加一个功能，就要在这个类里戳一个洞 → **肥控制器陷阱** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 模式的四个要素 |
|
||||
|
|
||||
| 要素 | 角色 | 示例 | |
|
||||
|------|------|------| |
|
||||
| Command接口 | 抽象的“订单” | `Command` | |
|
||||
| ConcreteCommand | 具体的订单 | `HelpCommand` | |
|
||||
| Invoker | 接单的前台 | `CrawlerController` | |
|
||||
| Receiver | 执行者 | `ConsoleView`、`ArticleRepository` | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 接口定义 |
|
||||
|
|
||||
```java |
|
||||
package com.crawler.command; |
|
||||
|
|
||||
import com.crawler.model.Article; |
|
||||
import java.util.List; |
|
||||
|
|
||||
public interface Command { |
|
||||
String getName(); |
|
||||
void execute(String[] args, List<Article> articles); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller 的变革：从 switch 到 Map |
|
||||
|
|
||||
```java |
|
||||
public class CrawlerController { |
|
||||
private Map<String, Command> commands = new HashMap<>(); |
|
||||
|
|
||||
public CrawlerController(ConsoleView view, List<Article> articles) { |
|
||||
commands.put("help", new HelpCommand(view)); |
|
||||
commands.put("list", new ListCommand(view)); |
|
||||
commands.put("crawl", new CrawlCommand(view)); |
|
||||
commands.put("exit", new ExitCommand(view)); |
|
||||
} |
|
||||
|
|
||||
public void handle(String input) { |
|
||||
// 解析命令 → 从 Map 取 Command → 调用 execute |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> **增加新命令：只需新建类，Controller 零改动！** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 对比：switch-case vs Command |
|
||||
|
|
||||
| 维度 | switch-case | Command模式 | |
|
||||
|------|-------------|-------------| |
|
||||
| 增加命令 | 要改 Controller | 新建一个类 | |
|
||||
| 多态体验 | 无 | `execute()` 多态 | |
|
||||
| 可测试性 | 难 | 每个 Command 单独测试 | |
|
||||
| 代码量 | 少 | 多，但更清晰 | |
|
||||
|
|
||||
> 🏨 **类比：酒店客房服务，前台只负责派单** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 5️⃣ Maven 模板与环境（5分钟） |
|
||||
|
|
||||
### 直接使用模板，不折腾配置 |
|
||||
|
|
||||
``` |
|
||||
my-crawler-template.zip |
|
||||
↓ 解压 + IDEA打开 |
|
||||
↓ 右键 pom.xml → Maven → Reload Project |
|
||||
↓ 运行 App.java |
|
||||
``` |
|
||||
|
|
||||
### 标准目录结构 |
|
||||
|
|
||||
``` |
|
||||
src/main/java/com/crawler/ |
|
||||
├── model/Article.java |
|
||||
├── view/ConsoleView.java |
|
||||
├── command/ |
|
||||
│ ├── Command.java |
|
||||
│ ├── CrawlCommand.java |
|
||||
│ ├── HelpCommand.java |
|
||||
│ ├── ListCommand.java |
|
||||
│ └── ExitCommand.java |
|
||||
└── controller/CrawlerController.java |
|
||||
``` |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 6️⃣ 代码落地（分步实现） |
|
||||
|
|
||||
### Model：Article 实体 |
|
||||
|
|
||||
```java |
|
||||
public class Article { |
|
||||
private String title; |
|
||||
private String url; |
|
||||
private String content; |
|
||||
// 构造器、getter/setter、toString |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 📦 只存放数据，没有任何输入输出代码 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## View：ConsoleView（ANSI常量集中管理） |
|
||||
|
|
||||
```java |
|
||||
public class ConsoleView { |
|
||||
private static final String ANSI_GREEN = "\033[32m"; |
|
||||
private static final String ANSI_RED = "\033[31m"; |
|
||||
// ... 其他常量 |
|
||||
|
|
||||
public void printSuccess(String msg) { |
|
||||
System.out.println(ANSI_GREEN + msg + ANSI_RESET); |
|
||||
} |
|
||||
public void printError(String msg) { ... } |
|
||||
public void display(List<Article> articles) { ... } |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✨ **所有颜色码集中定义 → 改主题只需改一处** |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Command 实现示例（HelpCommand） |
|
||||
|
|
||||
```java |
|
||||
public class HelpCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public HelpCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "help"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printInfo("Commands: crawl <url>, list, help, exit"); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ⚠️ 全部输出通过 `view`，绝不让 `System.out` 直接出现在这里 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## CrawlCommand（存根，下周填坑） |
|
||||
|
|
||||
```java |
|
||||
public class CrawlCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public CrawlCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "crawl"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
if (args.length < 2) { |
|
||||
view.printError("Usage: crawl <url>"); |
|
||||
return; |
|
||||
} |
|
||||
view.printInfo("Stub: Would crawl " + args[1]); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔍 **找茬点**：这里拼接字符串算是“业务逻辑”吗？留给大家用 AI 审计。 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## ExitCommand |
|
||||
|
|
||||
```java |
|
||||
public class ExitCommand implements Command { |
|
||||
private ConsoleView view; |
|
||||
public ExitCommand(ConsoleView v) { this.view = v; } |
|
||||
public String getName() { return "exit"; } |
|
||||
public void execute(String[] args, List<Article> articles) { |
|
||||
view.printSuccess("Bye!"); |
|
||||
System.exit(0); |
|
||||
} |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> ✅ 所有输出都通过 View → 将来改 GUI 只需换 View 实现 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Controller + main 组装 |
|
||||
|
|
||||
```java |
|
||||
// Controller 中持有 Map<String,Command> |
|
||||
// App.java 中： |
|
||||
ConsoleView view = new ConsoleView(); |
|
||||
List<Article> articles = new ArrayList<>(); |
|
||||
CrawlerController controller = new CrawlerController(view, articles); |
|
||||
view.printSuccess("Welcome to CLI Crawler!"); |
|
||||
while (true) { |
|
||||
controller.handle(view.readLine()); |
|
||||
} |
|
||||
``` |
|
||||
|
|
||||
> 🔁 完成交互循环 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 7️⃣ 架构反思：共享 List<Article> 的隐患 |
|
||||
|
|
||||
### 当前问题 |
|
||||
|
|
||||
- 所有 Command 都直接拿到 `List<Article>` 引用 |
|
||||
- 任何一个命令都可以随意增、删、改列表 |
|
||||
- 数据完全“裸奔” |
|
||||
|
|
||||
> 🚨 就像酒店所有员工都能进保险箱 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 提问 |
|
||||
|
|
||||
- 如果 `CrawlCommand` 不小心把 `null` 塞进列表，`ListCommand` 会怎样？ |
|
||||
- 如果我们要在添加文章时写日志，现在的设计能优雅实现吗？ |
|
||||
|
|
||||
### 预告解决方案（W10） |
|
||||
|
|
||||
- **策略模式** + **仓库层（ArticleRepository）** |
|
||||
- 封装 `List`，对外只暴露 `add()`、`getAll()` 等安全接口 |
|
||||
|
|
||||
> W9 搭骨架，W10 装上盔甲 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 8️⃣ 实践任务（现场5分钟） |
|
||||
|
|
||||
### 必做项 |
|
||||
|
|
||||
1. 使用 Maven 模板创建项目 |
|
||||
2. 实现完整包结构（model/view/command/controller） |
|
||||
3. 实现 4 个 Command：help / list / crawl / exit |
|
||||
4. `list` 能展示已抓取的文章（目前存根即可） |
|
||||
5. 运行并测试循环 |
|
||||
|
|
||||
### 额外加分：代码找茬 |
|
||||
|
|
||||
- 检查是否仍有 `System.out` 直接调用 |
|
||||
- 检查 ANSI 码是否硬编码在多个地方 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 验收标准 |
|
||||
|
|
||||
- [x] Maven 编译通过 |
|
||||
- [x] Command 接口和 4 个实现在不同文件 |
|
||||
- [x] Controller 里没有 switch-case |
|
||||
- [x] 新增命令只需新建类，不改 Controller |
|
||||
- [x] list 能正确显示空列表 |
|
||||
- [x] 所有输出均通过 `ConsoleView` |
|
||||
- [x] ANSI 颜色码集中定义为常量 |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 9️⃣ 课后作业 |
|
||||
|
|
||||
### 必做 |
|
||||
|
|
||||
1. **完善 Article**：增加 `author`、`publishDate` 字段 |
|
||||
2. **★ HistoryCommand**：记录用户输入过的所有命令（用 `List<String>`） |
|
||||
3. **AI 架构审计**：将类名发给 AI，指令： |
|
||||
> “作为Java架构审计师，请检查我的MVC三层划分是否存在越权行为？” |
|
||||
|
|
||||
### 选做 |
|
||||
|
|
||||
- 命令别名（c 代替 crawl） |
|
||||
- URL 格式验证 |
|
||||
- 暗色主题（修改一处常量） |
|
||||
- 思考题：分析 `List<Article>` 共享引用的风险（200字小结） |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 🤖 AI 协同升级 |
|
||||
|
|
||||
### 架构审计师任务（必做） |
|
||||
|
|
||||
**步骤**： |
|
||||
1. 列出所有类名（不含方法实现） |
|
||||
2. 发给 AI |
|
||||
3. 指令：“检查 MVC 分层是否清晰，是否有越权行为” |
|
||||
|
|
||||
### 进阶探究（选做） |
|
||||
|
|
||||
> “假设我的 Command 接口中 execute 方法接收了一个 `List<Article>` 参数，请分析这种设计在工程上有什么隐患，并给出重构建议。” |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 📚 总结与过渡 |
|
||||
|
|
||||
### 本周成果 |
|
||||
|
|
||||
- ✅ 工程化包结构 |
|
||||
- ✅ MVC 分层清晰 |
|
||||
- ✅ Command 模式实现可扩展路由 |
|
||||
- ✅ 所有输出走 View，常量集中管理 |
|
||||
|
|
||||
### 下周预告 |
|
||||
|
|
||||
- **策略模式**：封装爬取算法 |
|
||||
- **仓库层（Repository）**：武装 `List<Article>`，解决共享隐患 |
|
||||
|
|
||||
> 🚀 从“写代码”到“造系统”，踏出坚实第一步！ |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## Q&A |
|
||||
|
|
||||
### 常见问题 |
|
||||
|
|
||||
| 问题 | 解答 | |
|
||||
|------|------| |
|
||||
| IDEA 不识别 pom.xml | 右键 → Maven → Reload Project | |
|
||||
| 中文乱码 | Settings → File Encodings → UTF-8 | |
|
||||
| 输出颜色乱码 | Windows 建议使用 Windows Terminal | |
|
||||
| 我的 System.out 被批评 | View 才是唯一输出出口 | |
|
||||
|
|
||||
--- |
|
||||
|
|
||||
## 谢谢！ |
|
||||
|
|
||||
### 课件已上传，模板在课程群 |
|
||||
|
|
||||
**保持工程洁癖，下周见！** |
|
||||
Loading…
Reference in new issue