关于Java使用策略模式（一）

一、业务场景

做了微信支付，支付宝支付，然后突然要加一个银联支付，那么如果代码方法一起就会导致代码不是很好操作所以，采用策略模式进行。

二、直接上代码

1、策略接口：执行的方法

package com.cxy.ssp.strategy;

public interface Strategy {
    String getVpcList(DemoPojo demoPojo);
}

2、实体类：

package com.cxy.ssp.strategy;

public class DemoPojo {
    private String poolid;
    private String orderId;
    private String name;

    public String getPoolid() {
        return poolid;
    }

    public void setPoolid(String poolid) {
        this.poolid = poolid;
    }

    public String getOrderId() {
        return orderId;
    }

    public void setOrderId(String orderId) {
        this.orderId = orderId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public DemoPojo(String poolid, String orderId, String name) {
        this.poolid = poolid;
        this.orderId = orderId;
        this.name = name;
    }

    public DemoPojo() {

    }
}

3、实现类：

package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("A")
public class SA implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("A,getVpcList ==========="+demoPojo);
        return demoPojo.getName();
    }
}



package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("B")
public class SB implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("b,getVpcList ==========="+demoPojo);
        return demoPojo.getName();
    }
}



package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("C")
public class SC implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("c"+demoPojo);
        return demoPojo.getName();
    }
}

4、策略context

package com.cxy.ssp.strategy;

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

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;


/***、
 *通过Spring将实现Strategy的实现类都自动注入到strategyMap类中，
 * 当用户传入选择的资源池时，自动根据资源池id去对应的资源池实现中查找资源。
 *
 */
@Service
public class SimpleContext {
    @Autowired
    private final Map<String, Strategy> strategyMap = new ConcurrentHashMap<>();

    public SimpleContext(Map<String, Strategy> strategyMap) {
        this.strategyMap.clear();
        strategyMap.forEach((k, v)-> this.strategyMap.put(k, v));
    }

    public String getResource(DemoPojo demoPojo){
        return strategyMap.get(demoPojo.getPoolid()).getVpcList(demoPojo);
    }
}

5、策略服务L:

package com.cxy.ssp.controller;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.SimpleContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

@RestController
public class TestController {
    @Autowired
    private SimpleContext simpleContext;

    @PostMapping("/choose")
    public String choose(@RequestBody DemoPojo demoPojo){
        return simpleContext.getResource(demoPojo);
    }
}

package com.cxy.ssp;

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

@SpringBootApplication
public class SspApplication {

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

}

三、测试

 

 

四、改造代码

package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("A")
public class SA implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("A,getVpcList ==========="+demoPojo);
        return demoPojo.getName()+"a";
    }
}



package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("B")
public class SB implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("b,getVpcList ==========="+demoPojo);
        return demoPojo.getName()+"b";
    }
}



package com.cxy.ssp.strategy.impl;

import com.cxy.ssp.strategy.DemoPojo;
import com.cxy.ssp.strategy.Strategy;
import org.springframework.stereotype.Component;

@Component("C")
public class SC implements Strategy {
    @Override
    public String getVpcList(DemoPojo demoPojo) {
        System.out.println("c"+demoPojo);
        return demoPojo.getName()+"c";
    }
}

 

那么如果传输的那个poolid传输错误了改怎么处理呢：

服务器端报错误：说明没有这个方法，

那么可以在context中进行限制：

 首先判断是否包含，如果不包含，就可以直接threw一个异常，让前台直接显示。