thread15_4.java

很有用的课件

/**
 * FileName:Thread15_4
 * Description:
 * Copyright:    Copyright (c) 2002
 * Company:
 * @author:Liyunshan
 * @version 1.0
 */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Calendar;

//监听器接口
interface TimerListener
{
	void execute(MyTimer t);
}

//计时器
class MyTimer extends Thread
{
	private int interval;			//表示时间间隔的毫秒数
	private TimerListener target;	//表示执行动作目标对象

	public MyTimer(int i, TimerListener t)
	{
		interval = i;
		target = t;
		setDaemon(true);	//设置该线程在后台运行
	}

	public void run()
	{
		try
		{
			while(!interrupted())
			{
				sleep(interval);
				target.execute(this);
			}
		}
		catch(InterruptedException e){}
	}
}


class TimeField extends JTextField implements TimerListener
{
	public TimeField(int n)
	{
		super(n);
	}

	public void execute(MyTimer t)
	{
		Calendar calendar = Calendar.getInstance();	//得到系统日历
		int hour, minute, second;
		hour = calendar.get(Calendar.HOUR_OF_DAY);
		minute = calendar.get(Calendar.MINUTE);
		second = calendar.get(Calendar.SECOND);
		String time = hour + ":" + minute + ":" + second;
		setText(time);
	}
}

class TimerFrame extends JFrame
{
	TimeField timeField;	//用于显示时间
	MyTimer timer;			//计时器

	//类构建器
	public TimerFrame()
	{
		super("Timer");
		Container pane = getContentPane();
		timeField = new TimeField(5);
		JPanel paneTime = new JPanel();
		pane.add(paneTime, "Center");
		paneTime.add(timeField);
		setSize(200, 100);		//设置窗体大小
		setVisible(true);		//设置窗体为可见

		timer = new MyTimer(1000, timeField);	//时间间隔为1秒
		timer.start();

		timeField.setEditable(false);	//设置为不可编辑

		//关闭窗口事件
		addWindowListener(
			new WindowAdapter()
			{
				public void windowClosing(WindowEvent e)
				{
					System.exit(0);
				}
			}
		);
	}
}

public class Thread15_4
{
	public static void main(String args[])
	{
		TimerFrame frame = new TimerFrame();
		frame.setVisible(true);
	}
}