Java面向对象接口的应用实例练习

 1 interface USB
 2 {
 3     public void open();
 4     public void close();
 5 }
 6 
 7 class Upan implements USB
 8 {
 9     public void open()
10     {
11         System.out.println("Upan open");
12     }
13     public void close()
14     {
15         System.out.println("Upan close");
16     }
17 }
18 
19 class USBMouse implements USB
20 {
21     public void open()
22     {
23         System.out.println("USBMouse open");
24     }
25     public void close()
26     {
27         System.out.println("USBMouse close");
28     }
29 }
30 
31 class BookPC
32 {
33     public static void main(String[] args)
34     {
35         useUSB(new Upan());
36         useUSB(new USBMouse());
37     }
38     public static void useUSB(USB u)
39     {
40         u.open();
41         u.close();
42     }
43 }