java入门第二季–多态–多态中的引用类型转换

多态中的引用类型转换

代码

/javaDemo4/src/com/imooc/Animal.java

package com.imooc;  public class Animal {      } 

/javaDemo4/src/com/imooc/Dog.java

package com.imooc;  public class Dog extends Animal {  } 

/javaDemo4/src/com/imooc/Cat.java

package com.imooc;  public class Cat extends Animal {  } 

Initail.java

package com.imooc;  public class Initail {      public static void main(String[] args) {                  Dog dog = new Dog();         Animal animal = dog;  //自动类型提升，向上类型转换         Dog dog2 = (Dog)animal; //向下类型转换 强制类型转型                  if(animal instanceof Cat) {             Cat cat = (Cat)animal;         }else {             System.out.println("无法进行类型转换");         }     }  }