Demo59_多态_instanceof_亲子鉴定

//亲子鉴定 instanceof
/*已知条件:
动物类是dog类，mao类，people类的父类
Object是所有类的祖宗类，String是祖宗类的其中一个类
Object-->动物-->dog，mao，people
 */
package com.oop.多态另一种表现;

public class QZJD {
    public static void main(String[] args) {
        dog dog = new dog();
        System.out.println(dog instanceof dog);//ture
        System.out.println(dog instanceof 动物);//ture
        System.out.println(dog instanceof Object);//ture
        System.out.println("=======");
        Object object = new dog();
        System.out.println(object instanceof dog);//ture
        System.out.println(object instanceof 动物);//ture
        System.out.println(object instanceof mao);//false
        System.out.println(object instanceof people);//false
        System.out.println("========");
        动物 dw = new dog();
        System.out.println(dw instanceof dog);//ture
        System.out.println(dw instanceof 动物);//ture
        System.out.println(dw instanceof Object);//ture
        System.out.println(dw instanceof mao);//false
        System.out.println(dw instanceof people);//false
        //System.out.println(dw instanceof String);
        //因为dw(动物类)与String类没有任何关系所以打不出来这个判断词
        System.out.println("==========");
        //mao mao= new dog();//同类的引用不可以指向同类
        mao mao = new mao();//本类的引用可以指向本类

        /*
        总结:
        instanceof就是一个判断词
        1.首先判断A与B有没有关系
        2.再判断B与类名2是不是为父子关系或者本类关系，如果是那么就输出ture
        A instanceof B
        类名1 A=new 类名2();
         */
    }
}

                                  控制台输出结果