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java之多态(Polymorphic)、动态绑定(Dynamic Binding)、迟绑定(Late Binding)

今天,我们来说说java面向对象最核心的东西,多态。通过多态可以使我们的程序可复用性达到极致,这就是我们为什么要学多态的原因。

“多态”(Polymorphic)也叫“动态绑定”(Dynamic Binding)同时也叫“迟绑定”(Late Binding)。

动态绑定是指“在执行期间(而非编译期间)判断所引用对象的实际类型,根据其实际类型调用其相应的方法。”

程序代码:

public class TestPolymorphic{    public static void main(String args[]){            Animal animal = new Animal("animal");        Cat cat = new Cat("cat","blue");        Dog dog = new Dog("dog","black");                Lily l1 = new Lily("l1",animal);        Lily l2 = new Lily("l1",dog);                l1.myAnimalEnjoy();        l2.myAnimalEnjoy();    }}class Lily{    private String name;    private Animal animal;    public Lily(String name, Animal animal){        this.name = name;        this.animal = animal;    }    public void myAnimalEnjoy(){        animal.enjoy();    }}class Animal{    private String name;    public Animal(String name){        this.name = name;    }    public void enjoy(){        System.out.println("叫声~~~");    }}class Dog extends Animal{        private String forlorColor;    public Dog(String name,String forlorColor){        super(name);        this.forlorColor = forlorColor;    }    public void enjoy(){        System.out.println("dog叫声~~~");    }}class Cat extends Animal{        private String eyesColor;    public Cat(String name,String eyesColor){        super(name);        this.eyesColor = eyesColor;    }    public void enjoy(){        System.out.println("cat叫声~~~");    }}

程序运行结果:

总结:通过以上示例,我们发现多态必备的三个条件1、有继承2、有重写3、父类引用指向子类对象

java之多态(Polymorphic)、动态绑定(Dynamic Binding)、迟绑定(Late Binding)