使用策略模式 + 自动注册机制来构建旅游点评系统的搜索模块

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✅ 目标：

• 搜索模块支持不同内容类型（攻略、达人、游记等）
• 每种搜索逻辑用一个策略类表示
• 自动注册（基于注解 + Spring 容器）
• 新增搜索类型时，只需添加一个类 + 一个注解，无需改工厂、注册表等！

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️ 技术方案：

• Spring Boot
• 自定义注解 @SearchType("guide") 进行标记
• 启动时由 Spring 自动扫描并注册到 Map

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项目结构如下（Spring Boot）

search-system-springboot/
├── SearchSystemApplication.java
├── annotation/
│   └── SearchType.java
├── strategy/
│   ├── SearchStrategy.java
│   ├── GuideSearch.java
│   ├── ExpertSearch.java
│   ├── TravelNoteSearch.java
│   └── SearchStrategyFactory.java
└── controller/
    └── SearchController.java

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✅ 关键文件内容如下：

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SearchStrategy.java（策略接口）

package strategy;

public interface SearchStrategy {
    void search(String keyword);
}

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@SearchType 注解（用于标记策略类型）

package annotation;

import java.lang.annotation.*;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface SearchType {
    String value(); // 类型名称，如 "guide"
}

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SearchStrategyFactory.java（策略注册器）

package strategy;

import annotation.SearchType;
import jakarta.annotation.PostConstruct;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

import java.util.HashMap;
import java.util.Map;

@Component
public class SearchStrategyFactory {

    @Autowired
    private ApplicationContext context;

    private final Map<String, SearchStrategy> strategyMap = new HashMap<>();

    @PostConstruct
    public void init() {
        Map<String, Object> beans = context.getBeansWithAnnotation(SearchType.class);
        for (Object bean : beans.values()) {
            Class<?> clazz = bean.getClass();
            SearchType annotation = clazz.getAnnotation(SearchType.class);
            String type = annotation.value().toLowerCase();
            strategyMap.put(type, (SearchStrategy) bean);
        }
    }

    public SearchStrategy getStrategy(String type) {
        SearchStrategy strategy = strategyMap.get(type.toLowerCase());
        if (strategy == null) {
            throw new IllegalArgumentException("不支持的搜索类型: " + type);
        }
        return strategy;
    }
}

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示例策略类 GuideSearch.java

package strategy;

import annotation.SearchType;
import org.springframework.stereotype.Component;

@Component
@SearchType("guide")
public class GuideSearch implements SearchStrategy {
    public void search(String keyword) {
        System.out.println("搜索攻略：" + keyword);
    }
}

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示例策略类 ExpertSearch.java

package strategy;

import annotation.SearchType;
import org.springframework.stereotype.Component;

@Component
@SearchType("expert")
public class ExpertSearch implements SearchStrategy {
    public void search(String keyword) {
        System.out.println("搜索达人：" + keyword);
    }
}

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控制器 SearchController.java

package controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import strategy.SearchStrategy;
import strategy.SearchStrategyFactory;

@RestController
@RequestMapping("/search")
public class SearchController {

    @Autowired
    private SearchStrategyFactory factory;

    @GetMapping
    public String search(@RequestParam String type, @RequestParam String keyword) {
        SearchStrategy strategy = factory.getStrategy(type);
        strategy.search(keyword);
        return "搜索成功：" + type + " -> " + keyword;
    }
}

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启动类 SearchSystemApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SearchSystemApplication {
    public static void main(String[] args) {
        SpringApplication.run(SearchSystemApplication.class, args);
    }
}

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✅ 如何运行：

1. 新建 Spring Boot 项目（Maven/Gradle 都可以）
2. 创建上述包和类（annotation、strategy、controller）
3. 启动项目后访问：

http://localhost:8080/search?type=guide&keyword=台北夜市

输出：

搜索攻略：台北夜市

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如何新增一个搜索类型？

比如新增 TravelNoteSearch：

@Component
@SearchType("travelnote")
public class TravelNoteSearch implements SearchStrategy {
    public void search(String keyword) {
        System.out.println("搜索游记：" + keyword);
    }
}

就完事了，无需改动任何已有类！开闭原则 ✔️

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