1 package com.szxs.pet; 2  3 /** 4 * 宠物类 5 */ 6 public abstract class Pet { 7     private int health; 8      9     public int getHealth() {10         return health;11     }12 13     public void setHealth(int health) {14         this.health = health;15     }16 17     public abstract void toHospital();18 }

1 package com.szxs.pet; 2  3 /** 4 * 狗狗类 5 */ 6 public class Dog extends Pet { 7     /** 8      * 狗狗去医院 9      */10     public void toHospital() {11         System.out.println("狗狗看病");12     }13 }

1 package com.szxs.pet; 2  3 /** 4 * 企鹅类 5 */ 6 public class Penguin extends Pet { 7  8     /** 9      * 企鹅去医院10      */11     public void toHospital() {12         System.out.println("企鹅看病");13     }14 }

1 package com.szxs.pet; 2  3 /** 4 * 主人类 5 */ 6 public class Master { 7     /** 8      * 主人带宠物去看病 9      * 10      * @author 11      *12      */13     public void taketoHospital(Pet pet) {14         pet.toHospital();15     }16 }

1 package com.szxs.pet; 2  3 public class Test { 4  5     public static void main(String[] args) { 6         Master m=new Master(); 7  8         m.taketoHospital(new Dog()); 9         m.taketoHospital(new Penguin());10             11         }12 }