策略模式

策略模式（Strategy):它定义了算法家族，分别封装起来，让它们之间可以互相替换，此模式让算法的变化，不会影响到使用算法的客户。

场景

商场不同时间段活动。正常，打折，满减，等等

CashSuper

package com.healer.strategy;

import com.healer.domain.Goods;

import java.util.List;

/**

• @author tianzx
  
  
  /
  
  public interface CashSuper{
  
  
  /
  
  *
  
  *收款
  • @return
  • @param goodsList 商品列表
    
    */
    
    int acceptCash(List goodsList);
    
    }

CashNormal

package com.healer.strategy;

import com.healer.domain.Goods;

import java.util.List;

/**正常

• @author tianzx
  
  */
  
  public class CashNormal implements CashSuper {
  
  
  private String strategyName;

  public CashNormal(String strategyName) {
  
  
  this.strategyName = strategyName;
  
  }

  @Override
  
  public int acceptCash(List goodsList) {
  
  
  System.out.println(“今天活动：”+strategyName);
  
  int sum=0;
  
  /
  
  打印商品
  
  /
  
  goodsList.forEach(goods->System.out.println(goods.getGoodsName()+”—-“+goods.getGoodsNumber()+”—-“+goods.getGoodsPrice()));
  
  for (Goods goods:goodsList){
  
  
  sum+=goods.getGoodsNumber()*goods.getGoodsPrice();
  
  }

   return sum;
  

  }
  
  }

CashRebate

package com.healer.strategy;

import com.healer.domain.Goods;

import java.util.List;

/**打八折

• @author tianzx
  
  */
  
  public class CashRebate implements CashSuper {
  
  
  private String strategyName;
  
  private int discount;

  public CashRebate(String strategyName, int discount) {
  
  
  this.strategyName = strategyName;
  
  this.discount = discount;
  
  }

  @Override
  
  public int acceptCash(List goodsList) {
  
  
  System.out.println(“今天活动:”+strategyName);
  
  int sum = 0;
  
  /
  
  打印商品
  
  /
  
  goodsList.forEach(goods -> System.out.println(goods.getGoodsName() + “—-” + goods.getGoodsNumber() + “—-” + goods.getGoodsPrice()));
  
  for (Goods goods : goodsList) {
  
  
  sum += goods.getGoodsNumber() * goods.getGoodsPrice();
  
  }
  
  return sum*discount/10;
  
  }
  
  }

CashReturn

package com.healer.strategy;

import com.healer.domain.Goods;

import java.util.List;

/**满多少减多少

• @author tianzx
  
  */
  
  public class CashReturn implements CashSuper {
  
  
  private String strategyName;
  
  private int full;
  
  private int cashReturn;

  public CashReturn(String strategyName,int full, int cashReturn) {
  
  
  this.strategyName=strategyName;
  
  this.full = full;
  
  this.cashReturn = cashReturn;
  
  }

  @Override
  
  public int acceptCash(List goodsList) {
  
  
  System.out.println(“今天活动:”+strategyName);
  
  int sum = 0;
  
  /
  
  打印商品
  
  /
  
  goodsList.forEach(goods -> System.out.println(goods.getGoodsName() + “—-” + goods.getGoodsNumber() + “—-” + goods.getGoodsPrice()));
  
  for (Goods goods : goodsList) {
  
  
  sum += goods.getGoodsNumber() * goods.getGoodsPrice();
  
  }
  
  if (sum>full){
  
  
  sum=sum-cashReturn;
  
  }
  
  return sum;
  
  }
  
  }

CashContext

package com.healer.strategy;

import com.healer.domain.Goods;

import java.util.List;

/**收银逻辑

• @author tianzx
• @Date
  
  */
  
  public class CashContext {
  
  
  private CashSuper cashSuper;
  
  private List goodsList;
  
  public CashContext(CashSuper cashSuper,List goodsList){
  
  
  this.cashSuper=cashSuper;
  
  this.goodsList=goodsList;
  
  }
  
  public int getAcceptResult() {
  
  
  return cashSuper.acceptCash(goodsList);
  
  }

}

package com.healer.factory;

CashFactory

import com.healer.domain.Goods;

import com.healer.strategy.CashContext;

import com.healer.strategy.CashNormal;

import com.healer.strategy.CashRebate;

import com.healer.strategy.CashReturn;

import java.util.List;

/**策略工厂

• @author hspcadmin
  
  */
  
  public class CashFactory {
  
  
  public static void cashContext(String strategyName, List goodsList){
  
  
  switch (strategyName){
  
  
  case “无”:new CashContext(new CashNormal(strategyName),goodsList).getAcceptResult();
  
  break;
  
  case “满10000元减800元”:new CashContext(new CashReturn(strategyName,10000,800),goodsList).getAcceptResult();
  
  break;
  
  case “打八折”:new CashContext(new CashRebate(strategyName,8),goodsList).getAcceptResult();
  
  break;
  
  default:
  
  System.out.println(“今日没有此活动”);
  
  }
  
  }
  
  }

App

测试类

package com.healer;

import com.healer.domain.Goods;

import com.healer.factory.CashFactory;

import java.util.ArrayList;

import java.util.List;

/**

• Hello world!
• @author hspcadmin
  
  */
  
  public class App {
  
  
  public static void main(String[] args) {
  
  
  System.out.println(“Hello World!”);
  
  Goods goods1=new Goods(1,“电脑”,2,20000);
  
  Goods goods2=new Goods(2,“手机”,2,4000);
  
  Goods goods3=new Goods(3,“平板”,2,2000);
  
  Goods goods4=new Goods(4,“显示器”,2,1000);
  
  Goods goods5=new Goods(5,“主机”,2,6000);
  
  Goods goods6=new Goods(6,“耳机”,2,1000);
  
  List goodsList=new ArrayList<>();
  
  goodsList.add(goods1);
  
  goodsList.add(goods2);
  
  goodsList.add(goods3);
  
  goodsList.add(goods4);
  
  goodsList.add(goods5);
  
  goodsList.add(goods6);
  
  CashFactory.cashContext(“无”,goodsList);
  
  CashFactory.cashContext(“满10000元减800元”,goodsList);
  
  CashFactory.cashContext(“打八折”,goodsList);
  
  CashFactory.cashContext(“打七折”,goodsList);
  
  }
  
  }