Java多态的体现之继承

Posted 2020-07-02

/**
 * 
 * 功能：演示多态
 */
package com.litao;

public class Demo5 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        //体现多态
        /*Cat cat1 = new Cat();
        cat1.cry();
        
        Dog dog = new Dog();
        dog.cry();*/
        //自动判断右边引用是什么类型的
        //所有子类或孙子类的实例统统让一个父类来引用
//        Animal animal = new Cat();
//        //如果猫有cry方法，则调猫的cry,否则调Animal的cry
//        animal.cry();
//        
//        animal = new Dog();
//        animal.cry();
        
        Master master = new Master();
        master.feed(new Dog(), new Bone());
        master.feed(new Cat(), new Fish());
    }
}

//主人类
class Master{
    //给动物喂食物
    public void feed(Animal an, Food f)
    {
        an.eat();
        f.showName();
    }
}

class Food{
    String name;
    public void showName()
    {
        
    }
}

class Fish extends Food{
    public void showName()
    {
        System.out.println("鱼");
    }
}

class Bone extends Food{
    public void showName()
    {
        System.out.println("骨头");
    }
}



//动物类Animal
class Animal
{
    String name;
    int age;
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    
    //动物会叫
    public void cry()
    {
        System.out.println("不知道怎么叫...");
    }
    
    public void eat()
    {
        System.out.println("不知道喜欢吃什么");
    }
}

class Dog extends Animal
{
    //猫自己叫
    public void cry()
    {
        System.out.println("旺旺叫");        
    }
    
    //动物可以吃东西
    public void eat()
    {
        System.out.println("狗喜欢吃骨头");
    }
}

class Cat extends Animal
{
    //猫自己叫
    public void cry()
    {
        System.out.println("猫猫叫");        
    }
    
    public void eat()
    {
        System.out.println("猫喜欢吃鱼");
    }
}