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java入门第二季--多态--java中的多态

java中的多态

引用的多态

/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/Initail.java

package com.imooc;

public class Initail {

    public static void main(String[] args) {

        Animal obj1 = new Animal();
        Animal obj2 = new Dog();  //父类的引用是可以指向子类对象
        //Dog obj3 = new Animal();  //报错


    }

}

方法多态

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

package com.imooc;

public class Animal {
    public void eat() {
        System.out.print("动物具有吃的能力");
    }
}

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

package com.imooc;

public class Dog extends Animal {
    public void eat() {
        System.out.print("狗具有吃肉的能力");
    }
    public void watchDoor() {
        System.out.print("狗具有看门的能力");
    }
}

/javaDemo4/src/com/imooc/Initail.java

package com.imooc;

public class Initail {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Animal obj1 = new Animal();
        Animal obj2 = new Dog();  //父类的引用是可以指向子类对象
        //Dog obj3 = new Animal();  //报错
        Animal obj3 = new Cat();
        obj1.eat();
        
        obj2.eat();
        obj3.eat();
//        obj2.watchDoor();
    }

}

java入门第二季--多态--java中的多态