Java 多态中继承的转型详解与用法分析

public class Fu {
  public   void show(){
        System.out.println("fu:1024程序员节");
    }
  public void play(){
      System.out.println("fu:1024不见不散");
    }
}

public class Zi extends Fu {
    @Override
    public void show() {//重写fu类中的show方法
        super.show();
        System.out.println("zi:1024来了呀");
    }
    public void game(){
        System.out.println("zi：写篇博客提提神");
    }
    public void juan(){
        System.out.println("zi：全员卷王");
    }
}

public class FuZiDemo {
    public static void main(String[] args) {
        Fu f=new Zi();//向上转型
        Zi z=(Zi)f;//向下转型
        z.show();
        z.game();
        z.juan();
        z.play();
    }
}

public class FuZiDemo {
    public static void main(String[] args) {
 
        Zi z=new Zi();//通过子类直接创建对象
        z.show();
        z.game();
        z.juan();
        z.play();
 
    }
}

public class Demo11 {
    public static void main(String[] args) {
     Animal a=new Dog();
      Dog g=(Dog)a;
     Cat c=(Cat)a;//??能否成功
 
    }
}

public class Demo11 {
    public static void main(String[] args) {
     Animal a=new Dog();
    if(a instanceof Dog){
      Dog g=(Dog)a;
    }
      if( a instanceof Cat){//判断作用
        Cat c=(Cat)a;
      }
    }
}