http://www.verejava.com/?id=16992843565554

/**
    题目: 孩子吃(苹果,葡萄,芒果)

    思路：
        1. 抽象出类 : 孩子(Baby), 苹果(Apple),葡萄(Grape)
        2. 找出类的关系: 苹果,葡萄 -> 孩子
        3. 找出属性: 孩子(姓名,苹果引用,葡萄引用)  苹果(名称)  葡萄(名称)
        4. 找出方法: 孩子吃(eat)苹果或者葡萄
*/
public class Polymorphism2 {
    
    public static void main(String[] args) {
        //实例化一个Baby
        Baby baby = new Baby("李明");

        //实例化一个苹果 和 一个葡萄
        Apple apple = new Apple("红富士");
        Grape grape = new Grape("黑葡萄");
        Mango mango = new Mango("大芒果");

        //李明吃苹果和葡萄
        baby.eat(apple);
        System.out.println(baby.getName() + " 高兴的说我吃了 " + baby.getApple().getName());
        baby.eat(grape);
        System.out.println(baby.getName() + " 高兴的说我吃了 " + baby.getGrape().getName());
        baby.eat(mango);
        System.out.println(baby.getName() + " 高兴的说我吃了 " + baby.getMango().getName());

    }
}

class Baby {
    
    private Apple apple;
    private Grape grape;
    private Mango mango;
    private String name;

    public Baby(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }

    public Apple getApple() {
        return this.apple;
    }

    public Grape getGrape() {
        return this.grape;
    }

    public Mango getMango() {
        return this.mango;
    }

    //吃苹果
    public void eat(Apple apple) {
        this.apple = apple;
    }

    //吃葡萄
    public void eat(Grape grape) {
        this.grape = grape;
    }

    //吃芒果
    public void eat(Mango mango) {
        this.mango = mango;
    }

}

class Apple {
    
    private String name;

    public Apple(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }
}

class Grape {
    
    private String name;

    public Grape(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }

}

class Mango {
    
    private String name;

    public Mango(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }

}

http://www.verejava.com/?id=16992843565554