怎么用Java实现精确到毫秒的倒计时器

[yugang1219]

现在要用Java实现一个倒计时器，我采用的办法是：先获得总的毫秒数matchTime，然后用Timer，每隔一毫秒就让matchTime减1，然后再把matchTime转换成时间的格式。但是这样做出来的时间走的比现实时间要慢得多，如果改成每100秒减100次，就和现实时间差不多了，这也就是说精确到了0.1秒。但是有没有办法精确到毫秒呢？

[椅子]

看起来是timer的精度不够

[小爽昵称已被占用]

getMilliseconds（），返回毫秒数。

[ldy214]

System.nanoTime()

[流子]

windows系统的计时精确度在15毫秒左右。

[sagezk]

import java.util.Date;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.awt.Font;
import java.awt.BorderLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseAdapter;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;

/**
 * TimerFrame - 倒计时窗口
 * @author SageZk
 * @version 1.0
 */
@SuppressWarnings("serial")
public class TimerFrame extends JFrame {

	private long time = (long) (1.2 * 60 * 1000L);  //倒计时时间（单位毫秒）
	private JLabel lblTime;
	private Thread runner;

	public TimerFrame() {
		super("TimerFrame");
		this.lblTime = new JLabel("单击开始");
		this.lblTime.setFont(new Font("Monospaced", Font.BOLD, 60));
		this.lblTime.setHorizontalAlignment(SwingConstants.CENTER);
		this.lblTime.addMouseListener(new MouseAdapter() {
			public void mouseClicked(MouseEvent e) {
				if (runner != null) runner.start();
			}
		});
		this.runner = new Thread(new Runnable() {
			public void run() {
				Date t = new Date();
				StringWriter sw = new StringWriter();
				StringBuffer sb = sw.getBuffer();
				PrintWriter pw = new PrintWriter(sw);
				long cur = 0L, end = System.currentTimeMillis() + time;
				while ((cur = end - System.currentTimeMillis()) > 0) {
					t.setTime(cur);
					pw.format("%1$tM:%1$tS.%tL", t);
					pw.flush();
					lblTime.setText(sb.toString());
					sb.setLength(0);
					try {
						Thread.sleep(6L);
					} catch (InterruptedException e) {
					}
				}
				lblTime.setText("00:00.000");
				try {
					Thread.sleep(1200L);
				} catch (InterruptedException e) {
				}
				lblTime.setText("Bomb!!!");
			}
		});
		this.runner.setDaemon(true);
		getContentPane().add(this.lblTime, BorderLayout.CENTER);
		setResizable(false);
		setBounds(0, 0, 460, 330);
		setLocationRelativeTo(null);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

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

}

[kulongge]

顶楼上的.

[chenhongxin]

import java.util.Date;
import java.io.PrintWriter;
import java.awt.Font;
import java.swing.JFrame;
public TimerFrame() {
super("TimerFrame");
this.lblTime = new JLabel("单击开始");
this.lblTime.setFont(new Font("Monospaced", Font.BOLD, 60));
this.lblTime.setHorizontalAlignment(SwingConstants.CENTER);
this.lblTime.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (runner != null) runner.start();
}
});
this.runner = new Thread(new Runnable() {
public void run() {
Date t = new Date();
StringWriter sw = new StringWriter();
StringBuffer sb = sw.getBuffer();
PrintWriter pw = new PrintWriter(sw);
long cur = 0L, end = System.currentTimeMillis() + time;
while ((cur = end - System.currentTimeMillis()) > 0) {
t.setTime(cur);
pw.format("%1$tM:%1$tS.%tL", t);
pw.flush();
lblTime.setText(sb.toString());
sb.setLength(0);
try {
Thread.sleep(6L);
} catch (InterruptedException e) {
}
}
lblTime.setText("00:00.000");
try {
Thread.sleep(1200L);
} catch (InterruptedException e) {
}
lblTime.setText("Bomb!!!");
}
});
this.runner.setDaemon(true);
getContentPane().add(this.lblTime, BorderLayout.CENTER);
setResizable(false);
setBounds(0, 0, 460, 330);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

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

}

[sagezk]

8楼的 Copy 我代码也不贴全，你那能通过编译吗？

[老紫竹]

用Timer 不就行了，quartz 也可以。

[j_bar]

看见线程我就头疼
怎么学那玩意？

[网站推广优化yetaoaiueo]

this.runner = new Thread(new Runnable() {
public void run() {
Date t = new Date();
StringWriter sw = new StringWriter();
StringBuffer sb = sw.getBuffer();
PrintWriter pw = new PrintWriter(sw);
long cur = 0L, end = System.currentTimeMillis() + time;
while ((cur = end - System.currentTimeMillis()) > 0) {
t.setTime(cur);
pw.format("%1$tM:%1$tS.%tL", t);
pw.flush();
lblTime.setText(sb.toString());
sb.setLength(0);
try {
Thread.sleep(6L);
} catch (InterruptedException e) {
}
}
lblTime.setText("00:00.000");
try {
Thread.sleep(1200L);
} catch (InterruptedException e) {
}
lblTime.setText("Bomb!!!");
}
});
this.runner.setDaemon(true);

[leosming]

[Quote=引用 6 楼 sagezk 的回复:]
Java codeimport java.util.Date;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.awt.Font;
import java.awt.BorderLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseAdapter;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingConstants;

/**
* TimerFrame - 倒计时窗口
* @author SageZk
* @version 1.0
*/
@SuppressWar…
[/Quote]

[冰思雨]

估计毫秒级，应该不好实现。我的机器，所有线程轮一圈，大概10毫秒。
所以，一旦程序中出现sleep，那么下次执行的毫秒数很有可能会滞后（每次最多10毫秒）。

JDK1.5当中的Timer类。楼主可以去看看。如果应用简单的话。应该能够达到要求。

[yujianbo1988]

xiexie

[云计算-魏军]

使用j2se来实现