31 changed files with 2077 additions and 0 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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{ |
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"git.ignoreLimitWarning": true |
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} |
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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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[.ShellClassInfo] |
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LocalizedResourceName=cil w9 |
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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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<slf4j.version>2.0.9</slf4j.version> |
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<logback.version>1.4.11</logback.version> |
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</properties> |
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<dependencies> |
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<dependency> |
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<groupId>org.slf4j</groupId> |
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<artifactId>slf4j-api</artifactId> |
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<version>${slf4j.version}</version> |
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</dependency> |
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<dependency> |
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<groupId>ch.qos.logback</groupId> |
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<artifactId>logback-classic</artifactId> |
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<version>${logback.version}</version> |
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</dependency> |
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</dependencies> |
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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.repository.ArticleRepository; |
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import com.example.datacollect.view.ConsoleView; |
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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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ArticleRepository repository = new ArticleRepository(); |
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CrawlerController controller = new CrawlerController(view, repository); |
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view.printSuccess("Welcome to CLI Crawler (W10)! 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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public interface Command { |
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String getName(); |
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void execute(String[] args, CommandContext context); |
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} |
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package com.example.datacollect.command; |
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import com.example.datacollect.repository.ArticleRepository; |
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import java.util.ArrayList; |
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import java.util.List; |
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public class CommandContext { |
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private final ArticleRepository repository; |
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private final List<String> history; |
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public CommandContext(ArticleRepository repository) { |
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this.repository = repository; |
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this.history = new ArrayList<>(); |
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} |
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public ArticleRepository getRepository() { |
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return repository; |
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} |
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public List<String> getHistory() { |
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return new ArrayList<>(history); |
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} |
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public void addToHistory(String command) { |
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history.add(command); |
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} |
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public int getHistorySize() { |
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return history.size(); |
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} |
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public void clearHistory() { |
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history.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.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 org.slf4j.Logger; |
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import org.slf4j.LoggerFactory; |
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import java.util.List; |
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public class CrawlCommand implements Command { |
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private static final Logger logger = LoggerFactory.getLogger(CrawlCommand.class); |
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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, CommandContext context) { |
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if (args.length < 3) { |
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view.printError("Usage: crawl <type> <url>"); |
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view.printError("Supported types: " + StrategyFactory.getSupportedTypes()); |
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return; |
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} |
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String type = args[1]; |
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String url = args[2]; |
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if (!StrategyFactory.hasStrategy(type)) { |
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view.printError("Unknown strategy type: " + type); |
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view.printError("Supported types: " + StrategyFactory.getSupportedTypes()); |
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return; |
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} |
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try { |
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logger.info("Crawl started for: {}", url); |
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CrawlStrategy strategy = StrategyFactory.getStrategy(type); |
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List<Article> articles = strategy.crawl(url); |
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context.getRepository().addAll(articles); |
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view.printSuccess("Crawled " + articles.size() + " articles using " + type + " strategy"); |
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} catch (Exception e) { |
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view.printError("Crawl failed: " + e.getMessage()); |
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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.view.ConsoleView; |
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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, CommandContext context) { |
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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.view.ConsoleView; |
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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, CommandContext context) { |
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view.printInfo("Commands:"); |
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view.printInfo(" crawl <type> <url> - Crawl articles (types: blog, news)"); |
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view.printInfo(" list - List all articles"); |
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view.printInfo(" history - Show command history"); |
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view.printInfo(" help - Show this help"); |
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view.printInfo(" exit - Exit program"); |
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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.view.ConsoleView; |
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import java.util.List; |
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public class HistoryCommand implements Command { |
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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, CommandContext context) { |
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List<String> history = context.getHistory(); |
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if (history.isEmpty()) { |
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view.printInfo("暂无命令历史"); |
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return; |
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} |
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view.printInfo("命令历史:"); |
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for (int i = 0; i < history.size(); i++) { |
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System.out.println((i + 1) + ". " + history.get(i)); |
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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.view.ConsoleView; |
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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, CommandContext context) { |
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view.display(context.getRepository().findAll()); |
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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.CommandContext; |
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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.repository.ArticleRepository; |
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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.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 CommandContext context; |
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public CrawlerController(ConsoleView view, ArticleRepository repository) { |
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this.view = view; |
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this.context = new CommandContext(repository); |
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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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context.addToHistory(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, context); |
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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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|
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public String getTitle() { |
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return title; |
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} |
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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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|
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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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|
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public void setContent(String content) { |
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|
this.content = content; |
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} |
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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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|
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public void setAuthor(String author) { |
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|
this.author = author; |
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|
} |
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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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|
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public void setPublishDate(LocalDate publishDate) { |
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|
this.publishDate = publishDate; |
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|
} |
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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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@ -0,0 +1,38 @@ |
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package com.example.datacollect.repository; |
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import com.example.datacollect.model.Article; |
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|
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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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import java.util.Optional; |
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|
|
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|
public class ArticleRepository { |
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private final List<Article> articles = new ArrayList<>(); |
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|
|
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|
public void add(Article article) { |
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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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|
articles.addAll(articleList); |
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} |
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|
|
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|
public List<Article> findAll() { |
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|
return Collections.unmodifiableList(new ArrayList<>(articles)); |
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|
} |
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|
|
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|
public Optional<Article> findByUrl(String url) { |
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|
return articles.stream() |
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.filter(a -> a.getUrl().equals(url)) |
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.findFirst(); |
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|
} |
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|
|
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|
public int count() { |
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|
return articles.size(); |
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|
} |
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|
|
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|
public void clear() { |
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|
articles.clear(); |
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|
} |
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|
} |
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@ -0,0 +1,21 @@ |
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|
package com.example.datacollect.strategy; |
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|
|
||||
|
import com.example.datacollect.model.Article; |
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|
|
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|
import java.util.ArrayList; |
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|
import java.util.List; |
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|
|
||||
|
public class BlogStrategy implements CrawlStrategy { |
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|
@Override |
||||
|
public String getType() { |
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|
return "blog"; |
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|
} |
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|
|
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|
@Override |
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|
public List<Article> crawl(String url) { |
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|
List<Article> articles = new ArrayList<>(); |
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|
articles.add(new Article("Blog Post 1", url + "/post/1", "Blog content 1")); |
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|
articles.add(new Article("Blog Post 2", url + "/post/2", "Blog content 2")); |
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|
return articles; |
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|
} |
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|
} |
||||
@ -0,0 +1,10 @@ |
|||||
|
package com.example.datacollect.strategy; |
||||
|
|
||||
|
import com.example.datacollect.model.Article; |
||||
|
|
||||
|
import java.util.List; |
||||
|
|
||||
|
public interface CrawlStrategy { |
||||
|
String getType(); |
||||
|
List<Article> crawl(String url); |
||||
|
} |
||||
@ -0,0 +1,22 @@ |
|||||
|
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 String getType() { |
||||
|
return "news"; |
||||
|
} |
||||
|
|
||||
|
@Override |
||||
|
public List<Article> crawl(String url) { |
||||
|
List<Article> articles = new ArrayList<>(); |
||||
|
articles.add(new Article("News Article 1", url + "/news/1", "News content 1")); |
||||
|
articles.add(new Article("News Article 2", url + "/news/2", "News content 2")); |
||||
|
articles.add(new Article("News Article 3", url + "/news/3", "News content 3")); |
||||
|
return articles; |
||||
|
} |
||||
|
} |
||||
@ -0,0 +1,39 @@ |
|||||
|
package com.example.datacollect.strategy; |
||||
|
|
||||
|
import java.util.HashMap; |
||||
|
import java.util.Map; |
||||
|
import java.util.ServiceLoader; |
||||
|
|
||||
|
public class StrategyFactory { |
||||
|
private static final Map<String, CrawlStrategy> strategies = new HashMap<>(); |
||||
|
|
||||
|
static { |
||||
|
loadStrategies(); |
||||
|
} |
||||
|
|
||||
|
private static synchronized void loadStrategies() { |
||||
|
if (!strategies.isEmpty()) { |
||||
|
return; |
||||
|
} |
||||
|
ServiceLoader<CrawlStrategy> loader = ServiceLoader.load(CrawlStrategy.class); |
||||
|
for (CrawlStrategy strategy : loader) { |
||||
|
strategies.put(strategy.getType().toLowerCase(), strategy); |
||||
|
} |
||||
|
} |
||||
|
|
||||
|
public static CrawlStrategy getStrategy(String type) { |
||||
|
CrawlStrategy strategy = strategies.get(type.toLowerCase()); |
||||
|
if (strategy == null) { |
||||
|
throw new IllegalArgumentException("Unknown strategy type: " + type); |
||||
|
} |
||||
|
return strategy; |
||||
|
} |
||||
|
|
||||
|
public static boolean hasStrategy(String type) { |
||||
|
return strategies.containsKey(type.toLowerCase()); |
||||
|
} |
||||
|
|
||||
|
public static String getSupportedTypes() { |
||||
|
return String.join(", ", strategies.keySet()); |
||||
|
} |
||||
|
} |
||||
@ -0,0 +1,83 @@ |
|||||
|
package com.example.datacollect.test; |
||||
|
|
||||
|
import com.example.datacollect.command.CommandContext; |
||||
|
import com.example.datacollect.command.CrawlCommand; |
||||
|
import com.example.datacollect.command.ListCommand; |
||||
|
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 java.util.List; |
||||
|
|
||||
|
public class CrawlerTest { |
||||
|
|
||||
|
public static void main(String[] args) { |
||||
|
System.out.println("=== Crawler Test Suite ==="); |
||||
|
|
||||
|
testStrategyFactory(); |
||||
|
testArticleRepositoryImmutable(); |
||||
|
testCrawlToListFlow(); |
||||
|
|
||||
|
System.out.println("\n=== All tests passed! ==="); |
||||
|
} |
||||
|
|
||||
|
private static void testStrategyFactory() { |
||||
|
System.out.println("\n1. Testing StrategyFactory SPI loading..."); |
||||
|
|
||||
|
assert StrategyFactory.hasStrategy("blog") : "blog strategy should be registered"; |
||||
|
assert StrategyFactory.hasStrategy("news") : "news strategy should be registered"; |
||||
|
assert !StrategyFactory.hasStrategy("unknown") : "unknown strategy should not be registered"; |
||||
|
|
||||
|
CrawlStrategy blogStrategy = StrategyFactory.getStrategy("blog"); |
||||
|
assert "blog".equals(blogStrategy.getType()) : "blog strategy type mismatch"; |
||||
|
|
||||
|
CrawlStrategy newsStrategy = StrategyFactory.getStrategy("news"); |
||||
|
assert "news".equals(newsStrategy.getType()) : "news strategy type mismatch"; |
||||
|
|
||||
|
System.out.println(" ✓ StrategyFactory loads strategies via SPI"); |
||||
|
System.out.println(" ✓ Supported types: " + StrategyFactory.getSupportedTypes()); |
||||
|
} |
||||
|
|
||||
|
private static void testArticleRepositoryImmutable() { |
||||
|
System.out.println("\n2. Testing ArticleRepository immutability..."); |
||||
|
|
||||
|
ArticleRepository repository = new ArticleRepository(); |
||||
|
repository.add(new Article("Test", "http://test.com", "content")); |
||||
|
|
||||
|
List<Article> articles = repository.findAll(); |
||||
|
|
||||
|
try { |
||||
|
articles.add(new Article("Should Not Add", "http://fail.com", "fail")); |
||||
|
assert false : "Should have thrown UnsupportedOperationException"; |
||||
|
} catch (UnsupportedOperationException e) { |
||||
|
System.out.println(" ✓ getAll() returns immutable view"); |
||||
|
} |
||||
|
|
||||
|
assert repository.count() == 1 : "Repository should have 1 article"; |
||||
|
System.out.println(" ✓ Repository count is correct"); |
||||
|
} |
||||
|
|
||||
|
private static void testCrawlToListFlow() { |
||||
|
System.out.println("\n3. Testing crawl → list flow..."); |
||||
|
|
||||
|
ConsoleView view = new ConsoleView(); |
||||
|
ArticleRepository repository = new ArticleRepository(); |
||||
|
CommandContext context = new CommandContext(repository); |
||||
|
|
||||
|
CrawlCommand crawlCommand = new CrawlCommand(view); |
||||
|
ListCommand listCommand = new ListCommand(view); |
||||
|
|
||||
|
crawlCommand.execute(new String[]{"crawl", "blog", "http://example.com"}, context); |
||||
|
assert repository.count() == 2 : "Should have 2 blog articles"; |
||||
|
System.out.println(" ✓ Crawl blog strategy: " + repository.count() + " articles"); |
||||
|
|
||||
|
crawlCommand.execute(new String[]{"crawl", "news", "http://news.com"}, context); |
||||
|
assert repository.count() == 5 : "Should have 5 articles total (2 blog + 3 news)"; |
||||
|
System.out.println(" ✓ Crawl news strategy: " + repository.count() + " articles total"); |
||||
|
|
||||
|
listCommand.execute(new String[]{"list"}, context); |
||||
|
System.out.println(" ✓ List command executed successfully"); |
||||
|
} |
||||
|
} |
||||
@ -0,0 +1,42 @@ |
|||||
|
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()); |
||||
|
} |
||||
|
} |
||||
|
} |
||||
@ -0,0 +1,2 @@ |
|||||
|
com.example.datacollect.strategy.BlogStrategy |
||||
|
com.example.datacollect.strategy.NewsStrategy |
||||
@ -0,0 +1,41 @@ |
|||||
|
<configuration> |
||||
|
<!-- 控制台输出 --> |
||||
|
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 文件输出 --> |
||||
|
<appender name="FILE" class="ch.qos.logback.core.FileAppender"> |
||||
|
<file>logs/application.log</file> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 滚动文件输出（按大小和时间分割） --> |
||||
|
<appender name="ROLLING_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender"> |
||||
|
<file>logs/application.log</file> |
||||
|
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"> |
||||
|
<fileNamePattern>logs/application.%d{yyyy-MM-dd}.%i.log</fileNamePattern> |
||||
|
<maxHistory>30</maxHistory> |
||||
|
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"> |
||||
|
<maxFileSize>10MB</maxFileSize> |
||||
|
</timeBasedFileNamingAndTriggeringPolicy> |
||||
|
</rollingPolicy> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 根日志级别 --> |
||||
|
<root level="INFO"> |
||||
|
<appender-ref ref="STDOUT" /> |
||||
|
<appender-ref ref="ROLLING_FILE" /> |
||||
|
</root> |
||||
|
|
||||
|
<!-- 特定包/类的日志级别 --> |
||||
|
<logger name="com.example.datacollect" level="DEBUG" /> |
||||
|
<logger name="com.example.datacollect.command.CrawlCommand" level="TRACE" /> |
||||
|
</configuration> |
||||
@ -0,0 +1,758 @@ |
|||||
|
--- |
||||
|
|
||||
|
# 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） |
||||
@ -0,0 +1,2 @@ |
|||||
|
com.example.datacollect.strategy.BlogStrategy |
||||
|
com.example.datacollect.strategy.NewsStrategy |
||||
@ -0,0 +1,41 @@ |
|||||
|
<configuration> |
||||
|
<!-- 控制台输出 --> |
||||
|
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender"> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 文件输出 --> |
||||
|
<appender name="FILE" class="ch.qos.logback.core.FileAppender"> |
||||
|
<file>logs/application.log</file> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 滚动文件输出（按大小和时间分割） --> |
||||
|
<appender name="ROLLING_FILE" class="ch.qos.logback.core.rolling.RollingFileAppender"> |
||||
|
<file>logs/application.log</file> |
||||
|
<rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy"> |
||||
|
<fileNamePattern>logs/application.%d{yyyy-MM-dd}.%i.log</fileNamePattern> |
||||
|
<maxHistory>30</maxHistory> |
||||
|
<timeBasedFileNamingAndTriggeringPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedFNATP"> |
||||
|
<maxFileSize>10MB</maxFileSize> |
||||
|
</timeBasedFileNamingAndTriggeringPolicy> |
||||
|
</rollingPolicy> |
||||
|
<encoder> |
||||
|
<pattern>%d{yyyy-MM-dd HH:mm:ss} [%thread] %-5level %logger{36} - %msg%n</pattern> |
||||
|
</encoder> |
||||
|
</appender> |
||||
|
|
||||
|
<!-- 根日志级别 --> |
||||
|
<root level="INFO"> |
||||
|
<appender-ref ref="STDOUT" /> |
||||
|
<appender-ref ref="ROLLING_FILE" /> |
||||
|
</root> |
||||
|
|
||||
|
<!-- 特定包/类的日志级别 --> |
||||
|
<logger name="com.example.datacollect" level="DEBUG" /> |
||||
|
<logger name="com.example.datacollect.command.CrawlCommand" level="TRACE" /> |
||||
|
</configuration> |
||||
@ -0,0 +1,5 @@ |
|||||
|
#Generated by Maven |
||||
|
#Thu Apr 30 11:50:54 CST 2026 |
||||
|
artifactId=datacollect-cli |
||||
|
groupId=com.example |
||||
|
version=0.1.0 |
||||
@ -0,0 +1,17 @@ |
|||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\view\ConsoleView.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\CommandContext.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\Main.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\HelpCommand.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\ExitCommand.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\model\Article.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\strategy\NewsStrategy.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\CrawlCommand.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\Command.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\repository\ArticleRepository.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\strategy\BlogStrategy.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\ListCommand.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\controller\CrawlerController.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\strategy\StrategyFactory.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\command\HistoryCommand.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\strategy\CrawlStrategy.java |
||||
|
C:\Users\ruiruirui\java\w10\新增策略\src\main\java\com\example\datacollect\test\CrawlerTest.java |
||||
@ -0,0 +1,530 @@ |
|||||
|
## 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); |
||||
|
} |
||||
|
} |
||||
|
``` |
||||
|
|
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> ✅ 所有输出都通过 View → 将来改 GUI 只需换 View 实现 |
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|
|
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|
--- |
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|
|
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|
## Controller + main 组装 |
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|
|
||||
|
```java |
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|
// Controller 中持有 Map<String,Command> |
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|
// App.java 中： |
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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!"); |
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|
while (true) { |
||||
|
controller.handle(view.readLine()); |
||||
|
} |
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|
``` |
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|
|
||||
|
> 🔁 完成交互循环 |
||||
|
|
||||
|
--- |
||||
|
|
||||
|
## 7️⃣ 架构反思：共享 List<Article> 的隐患 |
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|
|
||||
|
### 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 |
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|
- 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