JAVA基础-多态

多态 polymophism: 动态绑定, 迟绑定, 指在执行期间(java), 而不是编译期间(javac), 判断所引用对象的实际类型, 根据实际类型调用响应的方法.

3个条件: 1. 继承 2. 重写 3. 父类引用指向子类对象

优点: 可扩展

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abstract class Animal {
  private String name;
  Animal(String name) {this.name = name;}
   
  public void enjoy(){
    System.out.println("叫声......");
  }
   
  //public abstract void enjoy();
}
 
//abstract <br>class Cat extends Animal {
  private String eyesColor;
  Cat(String n,String c) {super(n); eyesColor = c;}
   
  public void enjoy() {
    System.out.println("猫叫声......");
  }
   
  //public abstract void enjoy();
}
 
class Dog extends Animal {
  private String furColor;
  Dog(String n,String c) {super(n); furColor = c;}
  
  public void enjoy() {
    System.out.println("狗叫声......");
  }
}
 
class Bird extends Animal {
     Bird() {
         super("bird");
     }
     public void enjoy() {
    System.out.println("鸟叫声......");
  }
}
 
class Lady {
    private String name;
    private Animal pet;
    Lady(String name,Animal pet) {
        this.name = name; this.pet = pet;
    }
    public void myPetEnjoy(){pet.enjoy();}
}
 
public class Test {
    public static void main(String args[]){
        Cat c = new Cat("catname","blue");
        Dog d = new Dog("dogname","black");
        Bird b = new Bird();
        Lady l1 = new Lady("l1",c);
        Lady l2 = new Lady("l2",d);
        Lady l3 = new Lady("l3",b);
        l1.myPetEnjoy();
        l2.myPetEnjoy();
        l3.myPetEnjoy();
    }
}

  

 

posted @   wujixing909  阅读(129)  评论(0编辑  收藏  举报
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