上传Command包

project/src/main/java/org/example/command/.gitignore

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+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+.kotlin
+
+### IntelliJ IDEA ###
+.idea/modules.xml
+.idea/jarRepositories.xml
+.idea/compiler.xml
+.idea/libraries/
+*.iws
+*.iml
+*.ipr
+
+### Eclipse ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/
+
+### Mac OS ###
+.DS_Store

project/src/main/java/org/example/command/Article.java

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+package org.example.model;
+
+public class Article {
+    private String title;
+    private String url;
+
+    // 构造方法
+    public Article(String title, String url) {
+        this.title = title;
+        this.url = url;
+    }
+
+    // Getter 方法 (非常重要，SearchCommand 里要用到)
+    public String getTitle() {
+        return title;
+    }
+
+    public String getUrl() {
+        return url;
+    }
+
+    @Override
+    public String toString() {
+        return "标题: " + title + "\n链接: " + url;
+    }
+}

project/src/main/java/org/example/command/Command.java

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+package org.example.command;
+
+public interface Command {
+    void execute();
+
+    void execute(String[] args);
+}

project/src/main/java/org/example/command/CrawlerException.java

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+package org.example.exception;
+
+// 自定义运行时异常
+public class CrawlerException extends RuntimeException {
+    public CrawlerException(String message) {
+        super(message);
+    }
+
+    public CrawlerException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

project/src/main/java/org/example/command/CrawlerService.java

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+package org.example.service;
+
+import org.example.exception.CrawlerException;
+import org.example.model.Article;
+import org.example.strategy.BaiduStrategy;
+import org.example.strategy.BingStrategy;
+import org.example.strategy.CrawlerStrategy;
+import org.example.strategy.CsdnStrategy;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class CrawlerService {
+
+    /**
+     * 聚合搜索：同时调用所有策略进行搜索
+     */
+    public List<Article> search(String keyword) throws CrawlerException {
+        if (keyword == null || keyword.trim().isEmpty()) {
+            throw new CrawlerException("关键词不能为空！");
+        }
+
+        System.out.println("Service层: 正在调度所有爬虫策略...");
+
+        List<CrawlerStrategy> strategies = new ArrayList<>();
+        strategies.add(new BaiduStrategy());
+        strategies.add(new BingStrategy());
+        strategies.add(new CsdnStrategy());
+
+        List<Article> allResults = new ArrayList<>();
+
+        for (CrawlerStrategy strategy : strategies) {
+            try {
+                System.out.println("正在爬取 [" + strategy.getName() + "] ...");
+
+                // 调用具体策略的 crawl 方法
+                List<Article> results = strategy.crawl(keyword);
+
+                // 将当前策略的结果添加到总列表中
+                allResults.addAll(results);
+
+                System.out.println("[" + strategy.getName() + "] 爬取完成，获取到 " + results.size() + " 条数据。");
+
+            } catch (Exception e) {
+                // 捕获单个策略的异常，防止因为一个网站挂了导致整个程序崩溃
+                System.err.println("警告: [" + strategy.getName() + "] 爬取失败: " + e.getMessage());
+            }
+        }
+
+        System.out.println("搜索结束，共获取到 " + allResults.size() + " 条结果。");
+        return allResults;
+    }
+}

project/src/main/java/org/example/command/Main.java

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+package org.example;
+
+import org.example.command.Command;
+import org.example.command.SearchCommand;
+import org.example.service.CrawlerService;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("简易搜索引擎启动");
+
+        // 1. 初始化 Service
+        CrawlerService service = new CrawlerService();
+
+        // 2. 初始化 Command (注入 Service)
+        Command searchCmd = new SearchCommand(service);
+
+        // 3. 执行命令
+        searchCmd.execute();
+
+        System.out.println("程序结束");
+    }
+}

project/src/main/java/org/example/command/SearchCommand.java

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+package org.example.command;
+
+import org.example.exception.CrawlerException;
+import org.example.model.Article;
+import org.example.service.CrawlerService;
+
+import java.util.List;
+import java.util.Scanner;
+
+/**
+ * 处理搜索指令的具体命令类
+ */
+public class SearchCommand implements Command {
+
+    private final CrawlerService crawlerService;
+
+    // 构造方法注入 Service
+    public SearchCommand(CrawlerService crawlerService) {
+        this.crawlerService = crawlerService;
+    }
+
+    @Override
+    public void execute() {
+        Scanner scanner = new Scanner(System.in);
+        try {
+            System.out.println("请输入要搜索的关键词：");
+            String keyword = scanner.nextLine();
+
+            System.out.println("正在爬取数据，请稍候...");
+
+            // 调用 Service 层的搜索方法
+            List<Article> results = crawlerService.search(keyword);
+
+            if (results.isEmpty()) {
+                System.out.println("未找到相关结果。");
+            } else {
+                System.out.println("共找到 " + results.size() + " 条结果：");
+                for (Article article : results) {
+                    System.out.println(article);
+                }
+            }
+
+        } catch (CrawlerException e) {
+            // 捕获我们在 Service 层抛出的自定义异常
+            System.err.println("搜索失败：" + e.getMessage());
+        } catch (Exception e) {
+            System.err.println("发生未知错误：" + e.getMessage());
+        }
+    }
+
+    @Override
+    public void execute(String[] args) {
+
+    }
+}

project/src/main/java/org/example/command/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>Homework</artifactId>
+    <version>1.0-SNAPSHOT</version>
+
+    <properties>
+        <maven.compiler.source>25</maven.compiler.source>
+        <maven.compiler.target>25</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    <dependencies>
+        <!-- Jsoup: 用于解析 HTML 网页 -->
+        <dependency>
+            <groupId>org.jsoup</groupId>
+            <artifactId>jsoup</artifactId>
+            <version>1.15.3</version>
+        </dependency>
+
+        <!-- HttpClient: 用于发送网络请求 (可选，Jsoup自带简单的连接功能，但HttpClient更强大) -->
+        <!-- 这里先只加 Jsoup 简化起步，如果后面需要复杂的并发爬取再加这个 -->
+    </dependencies>
+</project>