二、策略模式-商场促销活动

1 package secondStrategy;
2 
3 public abstract class CashSuper {
4     public abstract double acceptCash(double money);
5 }

 1 package secondStrategy;
 2 
 3 public class CashNormal extends CashSuper {
 4 
 5     @Override
 6     public double acceptCash(double money) {
 7         return money;
 8     }
 9 
10 }

 1 package secondStrategy;
 2 
 3 // 打折类
 4 public class CashRebate extends CashSuper {
 5     private double moneyRebate=0;
 6     // 构造方法，初始化时应传入折扣
 7     public  CashRebate(double moneyRe) {
 8         this.moneyRebate=moneyRe;
 9     }
10     @Override
11     public double acceptCash(double money) {
12         double result=0;
13         result=money*moneyRebate;
14         return result;
15     }
16 
17 }

 1 package secondStrategy;
 2 
 3 public class CashReturn extends CashSuper {
 4     private double moneyCondition=0; //满减门槛
 5     private double moneyReturn=0;  // 满减金额
 6     
 7     public  CashReturn(double moneyCon,double moneyRe) {
 8         // TODO Auto-generated constructor stub
 9         this.moneyCondition=moneyCon;
10         this.moneyReturn=moneyRe;
11     }
12     
13     @Override
14     public double acceptCash(double money) {
15         double result=0;
16         result=money-(money/moneyCondition)*moneyReturn;
17         return result;
18     }
19 
20 }

 1 package secondStrategy;
 2 
 3 public class CashContext {
 4     private CashSuper cSuper;
 5     public   CashContext( String type) {
 6         switch (type) {
 7         case "打8折": this.cSuper=new CashRebate(0.8);    break;
 8         case "满100-30": this.cSuper=new CashReturn(100,30);break;
 9         default:this.cSuper=new CashNormal();
10             break;
11         }    
12     }
13     public double getResult(double money){
14         return this.cSuper.acceptCash(money);
15     }
16 }

package secondStrategy;

import java.text.DecimalFormat;

public class StrategyTest {
    public static void main(String[] args) {
        // 营业员提供信息
        double total=0;
        double price=2;
        int num=3;
        String promotions="打8折";//或者“满100-30”
        
        // 计算待付金额
        double totalPrice=price*num;
        total=total+totalPrice;
        
        switch (promotions) {
        case "打8折":total=total*0.8;break;
        case "满100-30": total=total-(total/100)*30; // "/"取整。“%”取余
        default:
            break;
        }
        DecimalFormat df = new DecimalFormat("#.##"); // 如果写成0.00，结果就一定是两个小数
        System.out.println("单价："+price+"；数量："+num+"；原价："+totalPrice+"；活动："+promotions+"；活动价："+df.format(total));
        
    }
}