java - day12 - InteraceTest

接口的实现、继承等

 package test.interfacedemo;
 import test.interfacedemo.Inter;

 public class InterfaceDemo {
     public static void main(String[] args){
         Inter o1 = new Foo();  //Foo实现接口Inter,类同于 向上造型
                                //通过变量o1可以调用接口Inter中定义的方法和常量
         System.out.println(Inter.PI);

         Inter3 t = new Boo();  //Boo实现接口Inter3
         t.a();
         t.c();
     }
 }

 package test.interfacedemo;

 public interface Inter{  //接口定义
     public static final double PI = 3.14;
     int NUM = 5;
     public abstract void show();
     void say(); //省略public abstract
 }

 class  Foo implements Inter{
     public void show(){}
     public void say(){}
 }

 interface Inter1{
     public abstract void a();
 }
 interface Inter2{
     public abstract void b();
 }
 interface Inter3 extends Inter1{
     public abstract void c();
 }

 abstract class Aoo{
     void d(){}
     abstract void e();
 }
 class Boo implements Inter3{
     void m(){}
     public void a(){
         System.out.println("a");
     }
     public void c(){
         System.out.println("c");
     }
 }
 class Coo implements Inter1,Inter2{
     public void a(){}
     public void b(){}
 }
 class Doo extends Aoo implements Inter1,Inter2{
     void e(){}
     public void a(){}
     public void b(){}
 }