java 继承与多态->方法调用优先级

调用顺序:

this.show(object)->super.show(object)->this.show(super(object))->super.show(super(object))

参见两个实例如下：

一：Animal和Dog类

public class Animal{
    public void speak(Animal p){
        System.out.println("Animal Speak!");
    }
}
 class Dog extends Animal{
    public void speak(Animal p){
        System.out.println("汪!");
    }
    public void speak(Dog p){
        System.out.println("汪汪!");
    }

  public static void main(String[] args) {
        Animal p1 = new Animal();
        Animal p2 = new Dog();//p2是animal类型。。。
        Dog p3 = new Dog();

        //因为p1 p2 p3 都是 Animal的子类。首先调用this.show(Obj)找不到匹配方法
      //然后调用this.show(super(Obj)),匹配成功，输出Animal speak
        p1.speak(p1);
        p1.speak(p2);
        p1.speak(p3);
        System.out.println("*******华丽丽的分割线*******");

        //参数p1 p2都是Animal类型，父类对象p2 调用子类重写后的speak方法，直接匹配
        p2.speak(p1);//汪
        p2.speak(p2);//汪

      //调用顺序：this.show(obj)(X)->super.show(obj)(X)->this.show(super(obj))(√)
        p2.speak(p3);//汪
        System.out.println("********华丽丽的分割线******");

      p3.speak(p1);
      p3.speak(p2);
      p3.speak(p3);
      
  }
 }

输出结果：

 

二：大一java期末考试多态考题

public class A {
    public String show(D obj){
        return "D in A";
    }
    public String show(A obj){
        return "A in A";
    }

    public static void main(String[] args) {
        A a1=new A();
        A a2=new B();
        B b=new B();
        C c=new C();
        D d=new D();
        System.out.println(a1.show(b));
        System.out.println(a1.show(c));
        System.out.println(a1.show(d));
        System.out.println("********华丽丽的分割线******");
        System.out.println(a2.show(b));
        System.out.println(a2.show(c));
        System.out.println(a2.show(d));
        System.out.println("********华丽丽的分割线******");
        System.out.println(b.show(b));
        System.out.println(b.show(c));
        System.out.println(b.show(d));

    }
}
class B extends A{
    public String show(B obj){
        return "B in B";
    }
    public String show(A obj){
        return "B in A";
    }

}
class C extends B{

}
class D extends B{

}

输出结果：

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