java

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(){}
}