基于@Autowired和@PostConstruct实现策略模式

考研 or 工作 ?

`package com.example.demo.designpattern.strategy;

public enum FutureChose { KAOYAN("KAOYAN", "考研"), WORK("WORK","工作");

private String name;
private String desc;

FutureChose(String name, String desc) {
    this.name = name;
    this.desc = desc;
}

} `

interface

`package com.example.demo.designpattern.strategy;

public interface Handler {

String getType();

String execute(String param);

} `

考研

`package com.example.demo.designpattern.strategy;

import org.springframework.stereotype.Component;

@Component public class KaoyanStragy implements Handler{

[@Override](https://my.oschina.net/u/1162528)
public String getType() {
    return FutureChose.KAOYAN.name();
}

[@Override](https://my.oschina.net/u/1162528)
public String execute(String param) {
    return param +  "未来准备考研，勿扰";
}

} `

工作

`package com.example.demo.designpattern.strategy;

import org.springframework.stereotype.Component;

@Component public class WorkStragy implements Handler{

[@Override](https://my.oschina.net/u/1162528)
public String getType() {
    return FutureChose.WORK.name();
}

@Override
public String execute(String param) {
    return param +  "未来准备工作，勿扰";
}

} `

策略处理类

• 项目启动时将 所有子类注入到handlerList
• 项目启动时 将所有子类实现与枚举映射关系存储在hanlderMap

`package com.example.demo.designpattern.strategy;

import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct; import java.util.List; import java.util.Map; import java.util.function.Function; import java.util.stream.Collectors;

@Service public class StrategyMrt {

@Autowired
List<Handler> handlerList;

private Map<String,Handler> handlerMap;


@PostConstruct
private void init(){
    handlerMap= handlerList.stream().collect(Collectors.toMap(Handler::getType, Function.identity()));
}

/**
 *  根据传入枚举类型查找具体handler
 * @param futureChose
 * @return
 */
public Handler getHandler(FutureChose futureChose){
    return handlerMap.get(futureChose.name());
}

} `

测试

http://localhost:8080/handler/strategy?futureChose=KAOYAN

http://localhost:8080/handler/strategy?futureChose=WORK

如需新增新的策略,只需在枚举类中新增类型,新策略实现Handler即可

• 例如 : 我不想考研,也不想工作,而是想创业

则做如下操作:

新增创业枚举

`package com.example.demo.designpattern.strategy;

public enum FutureChose { KAOYAN("KAOYAN", "考研"), CHUANGYE("CHUANGYE", "创业"), WORK("WORK","工作");

private String name;
private String desc;

FutureChose(String name, String desc) {
    this.name = name;
    this.desc = desc;
}

} `

新增创业实现

`package com.example.demo.designpattern.strategy;

import org.springframework.stereotype.Component;

@Component public class ChuangyeStragy implements Handler{

@Override
public String getType() {
    return FutureChose.CHUANGYE.name();
}

@Override
public String execute(String param) {
    return param +  "未来准备创业，勿扰";
}

} `

效果如下:

测试