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