Java面向对象接口的应用实例练习

 interface USB
 {
     public void open();
     public void close();
 }

 class Upan implements USB
 {
     public void open()
     {
         System.out.println("Upan open");
     }
     public void close()
     {
         System.out.println("Upan close");
     }
 }

 class USBMouse implements USB
 {
     public void open()
     {
         System.out.println("USBMouse open");
     }
     public void close()
     {
         System.out.println("USBMouse close");
     }
 }

 class BookPC
 {
     public static void main(String[] args)
     {
         useUSB(new Upan());
         useUSB(new USBMouse());
     }
     public static void useUSB(USB u)
     {
         u.open();
         u.close();
     }
 }