1. package day0425;
   
2. 
   
3. import java.awt.Color;
   
4. import java.awt.FlowLayout;
   
5. import java.util.Calendar;
   
6. import java.util.TimerTask;
   
7. import java.util.Timer;
   
8. import javax.swing.JFrame;
   
9. import javax.swing.JTextField;
   
10. 
    
11. public class ThreadDemo2 extends JFrame
    
12. {
    
13. private static final long serialVersionUID = 1L;
    
14. private JTextField text;
    
15. ThreadDemo2()
    
16. {
    
17. getContentPane().setLayout(new FlowLayout());
    
18. text = new JTextField(20);
    
19. text.setEditable(false);
    
20. text.setForeground(Color.RED);
    
21. getContentPane().add(text);
    
22. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    
23. setBounds(200, 200, 300, 300);
    
24. setVisible(true);
    
25. Timer t = new Timer();
    
26. t.schedule(new TimerTask1(), 0,1000);
    
27. 
    
28. }
    
29. public static void main(String[]args)
    
30. {
    
31. new ThreadDemo2();
    
32. }
    
33. class TimerTask1 extends TimerTask
    
34. {
    
35. private String year;
    
36. private String month;
    
37. private String day;
    
38. private String hour;
    
39. private String min;
    
40. private String sec;
    
41. @Override
    
42. public void run() {
    
43. // TODO Auto-generated method stub
    
44. Calendar c = Calendar.getInstance();
    
45. year = ""+c.get(Calendar.YEAR);
    
46. month = ""+(c.get(Calendar.MONTH)+1);
    
47. if(month.length()<=1)
    
48. {
    
49. month = "0"+month;
    
50. }
    
51. day = ""+c.get(Calendar.DATE);
    
52. if(day.length()<=1)
    
53. {
    
54. day = "0"+day;
    
55. }
    
56. hour = ""+c.get(Calendar.HOUR);
    
57. if(hour.length()<=1)
    
58. {
    
59. hour = "0"+hour;
    
60. }
    
61. min = ""+c.get(Calendar.MINUTE);
    
62. if(min.length()<=1)
    
63. {
    
64. min = "0"+min;
    
65. }
    
66. sec=""+c.get(Calendar.SECOND);
    
67. if(sec.length()<=1)
    
68. {
    
69. sec = "0"+sec;
    
70. }
    
71. day = year + "-"+month+"-"+""+day+""+hour+":"+min+":"+sec;
    
72. text.setText(day);
    
73. }
    
74. }
    
75. 
    
76. }

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相关类：java.util.Timer

Timer类并不是线程类，但在其内部实现中，利用线程来执行定时任务

java.util.TimerTask

TimerTask类，是一个抽像类，它实现了Runnable.

实现步骤：

一、声明一个Timer(定时器)对像。

二、书写一个TimerTask(定时器任务)类。并声明它的对像。

三、将TimerTask的变量当成Timer变量的参数设置定时任务。

值得学习ing!