写个简单例子人吃饭，体现面向对象编程,包含接口，抽象类的用处。

一、定义一个接口类：Person,再定义三个类实现它，分别是RichMan,PoorMan,CommonMan。
二、定义一个抽象类：Food,再定义三个类继承它，分别是Noodle,Meat,MeatNoodle(肉丝面)。
三、定义一个方法类:EatFood,将Person 和Food进行关联。
四、最后，写个测试类:TestPersonEatFood

 

1、Person

package EatFood; /** * @author 王永涛 2009-12-28 晚上 弥补以前的遗憾！ * */ public interface Person { public void eat(Food food); }

 

2、 PoorMan

package EatFood; import java.sql.Date; /** * @author 王永涛 2009-12-28 晚上 * */ public class PoorMan implements Person { public void eat(Food food) { System.out.println("穷人的食物： "+food.getName()+" "+(new Date(System.currentTimeMillis()))); } }

 

3、RichMan

package EatFood; import java.sql.Date; /** * @author 王永涛 2009-12-28 晚上 * */ public class RichMan implements Person { public void eat(Food food) { System.out.println("富人的食物： "+food.getName()+" "+(new Date(System.currentTimeMillis()))); } }

 

4、CommonMan

package EatFood; import java.sql.Date; /** * @author 王永涛 2009-12-28 晚上 * */ public class CommonMan implements Person { public void eat(Food food) { System.out.println("普通人食物："+food.getName()+" "+(new Date(System.currentTimeMillis()))); } }

 

5、Food

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public abstract class Food { protected String name; public String getName() { return name; } public void setName(String name) { this.name = name; } }

 

6、Noodle

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public class Noodle extends Food { public Noodle(String name) { this.name=name; } }

 

7、Meat

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public class Meat extends Food { public Meat(String name) { this.name=name; } }

 

8、MeatNoodle

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public class MeatNoodle extends Food { public MeatNoodle(String name) { this.name=name; } }

 

9、EatFood

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public class EatFood { public void eat(Person person,Food food) { person.eat(food); } }

 

10、TestPersonEatFood

package EatFood; /** * @author 王永涛 2009-12-28 晚上 * */ public class TestPersonEatFood { /** * @param args */ public static void main(String[] args) { Person poor=new PoorMan(); Person rich=new RichMan(); Person common=new CommonMan(); Food noodle=new Noodle("面条"); Food meat=new Meat("肉丝"); Food meatnoodle=new MeatNoodle("肉丝面"); EatFood ef=new EatFood(); ef.eat(poor, noodle); ef.eat(rich, meat); ef.eat(common, meatnoodle); } }

 

总结：很幼稚，各位大牛，不要见笑，呵呵！