1 package com.szxs.goods;2 /**3  * 父类：商品类4  * @author 5  *6  */7 public abstract class Goods {8     public abstract void printPrice();9 }

1 package com.szxs.goods; 2  3 //食品类 4 public class Foods extends Goods { 5  6     public void printPrice() { 7         System.out.println("食品的价格是10元"); 8  9     }10 11 }

1 package com.szxs.goods; 2 /** 3  * 电视类 4  * @author  5  * 6  */ 7 public class TVs extends Goods { 8  9     public void printPrice() {10         System.out.println("电视的价格是4998元");11 12     }13 14 }

1 package com.szxs.goods; 2 /** 3  * 商场类 4  * @author  5  * 6  */ 7 public  class Mark { 8     public Goods  buy(int type) {         9         Goods goods=null;10         switch(type) {11         case 1:12             return goods=new Foods();            13         case 2:14             return goods=new TVs();15         }16         return goods;17         18     }19 }

1 package com.szxs.goods; 2  3 public class Test { 4  5     public static void main(String[] args) { 6         Mark m=new Mark(); 7         m.buy(1).printPrice(); 8     } 9 10 }