多态

多态也是JAVA面向对象的三大特征之一

多态【方法的多态】【对象的多态】
1、方法的多态:重写，重载
2、对象的多态
   a、一个对象的编译类型和运行类型可以不一致
   b、编译类型在定义对象时就确定了，不能改变
   c、运行类型可以改变【动态绑定机制】
多态的本质:父类的引用指向子类的对象

package com;
/*
* 多态
* */

public class Polymorphism {
    public static void main(String[] args) {
        
        //向上转型
        Animal animal = new Dog("旺财","雄性",8);
        System.out.println(animal.eat());
        //输出运行类型
        System.out.println(animal.getClass());
        Animal animal1 = new Cat("哈士奇","雌性","精神焕发");
        System.out.println(animal1.sleep());
        System.out.println(animal1.getClass());

        //向下转型
        Dog dog = (Dog)animal;
        System.out.println(dog.sleep());
        System.out.println(dog.getClass());

        Cat cat = (Cat) animal1;
        System.out.println(cat.eat());
        System.out.println(cat.getClass());

    }
}
class Animal{

    private String name;
    private String sex;

    public Animal(String name, String sex) {
        this.name = name;
        this.sex = sex;
    }

    public String sleep(){
        return sex + name + "正在睡觉";
    }

    public String eat(){
        return sex + name + "正在进食";
    }

}
class Dog extends Animal{

    private int age;

    public Dog(String name, String sex, int age) {
        super(name, sex);
        this.age = age;
    }

    public String sleep(){
        return age + "岁的" + super.sleep();
    }

}
class Cat extends Animal{

    private String status;

    public Cat(String name, String sex, String status) {
        super(name, sex);
        this.status = status;
    }

    public  String eat(){
        return status + "的" + super.eat();
    }

}