day10_20

 1 package com.lovo;
 2 
 3 import java.util.Calendar;
 4 
 5 /**
 6  * 时钟类
 7  * @author 叶鹏
 8  *
 9  */
10 public class Clock {
11     private int hour,minute,second;
12     
13     /**
14      * 系统时间构造器
15      */
16     public Clock(){
17         Calendar cal=Calendar.getInstance();
18         hour=cal.get(Calendar.HOUR);
19         minute=cal.get(Calendar.MINUTE);
20         second=cal.get(Calendar.SECOND);
21     }
22     public void go(){
23         second++;
24         if(second==60){
25             second=0;
26             minute++;
27             if(minute==0){
28                 minute=0;
29                 hour++;
30                 if(hour==4){
31                     hour=0;
32                 }
33             }
34         }
35         
36     }
37     /**
38      * 为保证低耦合性，用字符串显示时间
39      * @return
40      */
41     public String showTime(){
42         String time="";
43         if(hour<10){
44             time+="0";
45         }
46         time+=hour+":";
47         if(minute<10){
48             time+="0";
49         }
50         time+=minute+":";
51         if(second<10){
52             time+="0";
53         }
54         time+=second;
55         return time;
56     }
57 }

package com.lovo;

/**
 * 时钟类调用
 * @author 叶鹏
 *
 */

public class Clock1 {
    public static void main(String[] args) throws Exception {
    Clock c=new Clock();
    while(true){
        System.out.println(c.showTime());
        c.go();
        Thread.sleep(1000);
    }
    
}

}