Spring 实现策略模式

Posted 2022-11-13 咩咩文

1.策略接口

package org.apel.bowen.controller;

import java.math.BigDecimal;
/**
 * 计算价格的接口
 * @author Bowin
 *
 */
public interface Strategy 
	/**
     * 计算价格
     * @return
     */
   public  BigDecimal calculatePrice();

2.实现接口

package org.apel.bowen.controller;

import java.math.BigDecimal;

import org.springframework.stereotype.Service;
/**
 * 普通用户
 * @author Bowin
 *
 */
@Service("generalMember")
public class GeneralMember implements Strategy

	@Override
	public BigDecimal calculatePrice() 
		return new BigDecimal("100");
	

package org.apel.bowen.controller;

import java.math.BigDecimal;

import org.springframework.stereotype.Service;
/**
 * vip用户
 * @author Bowin
 *
 */
@Service("vipMember")
public class VipMember  implements Strategy

	@Override
	public BigDecimal calculatePrice() 
		return new BigDecimal("80");
	

package org.apel.bowen.controller;

import java.math.BigDecimal;

import org.springframework.stereotype.Service;
/**
 * 超级会员
 * @author Bowin
 *
 */
@Service("superMember")
public class SuperMember implements Strategy

	@Override
	public BigDecimal calculatePrice() 
		return new BigDecimal("1");
	

3.策略控制器

package org.apel.bowen.controller;

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

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
/**
 * 策略管理器
 * @author Bowin
 *
 */
@Component
public class StrategyContext 
	/**
	 *使用线程安全的ConcurrentHashMap存储所有实现Strategy接口的Bean
	 *key:beanName
	 *value：实现Strategy接口Bean
	 */
	private final Map<String, Strategy> strategyMap = new ConcurrentHashMap<>();
	
	 /**
     * 注入所有实现了Strategy接口的Bean
     * @param strategyMap
     */
    @Autowired
    public StrategyContext(Map<String, Strategy> strategyMap) 
        this.strategyMap.clear();
        strategyMap.forEach((k, v)-> this.strategyMap.put(k, v));
    
 
    /**
     * 计算价格
     * @param memberLevel   会员等级
     * @return              价格
     */
    public BigDecimal calculatePrice(String memberLevel) 
    	if(!StringUtils.isEmpty(memberLevel))
    		return strategyMap.get(memberLevel).calculatePrice();
    	
		return null;
    

4.客户端调用

package org.apel.bowen.controller;

import java.math.BigDecimal;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
/**
 * 前端控制器
 * @author Bowin
 *
 */
@Controller
@RequestMapping
public class HelloController 
	

	 @Autowired
	  private StrategyContext strategyContext;
	 
	  @RequestMapping("calculatePrice")
	  public @ResponseBody BigDecimal calculatePrice(String memberLevel) 
	        return strategyContext.calculatePrice(memberLevel);
	  
	 

5.访问测试: http://localhost:9999/calculatePrice?memberLevel=vipMember 返回 80