Java的功能还是很大的，毕竟是生活中很多地方都跟java相关，就连大家使用的小程序或者玩的游戏都是由java开发完成的，那java怎么在窗口中添加计时器?下面来我们就来给大家讲解一下。
应用名称：Java计时器
用到的知识：Java GUI编程
开发环境：win8+eclipse+jdk1.8
功能说明：计时功能，精确到1毫秒，可暂停。
效果图：
以下是源代码：
import javax.swing.*;
import java.awt.HeadlessException;
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
/**
* 计时器
*/
public class Timer extends JFrame
{
/**
*
*/
private static final long serialVersionUID = 1 L;
private static final String INITIAL_LABEL_TEXT = "00:00:00 000";
// 计数线程
private CountingThread thread = new CountingThread();
// 记录程序开始时间
private long programStart = System.currentTimeMillis();
// 程序一开始就是暂停的
private long pauseStart = programStart;
// 程序暂停的总时间
private long pauseCount = 0;
private JLabel label = new JLabel(INITIAL_LABEL_TEXT);
private JButton startPauseButton = new JButton("开始");
private JButton resetButton = new JButton("清零");
private ActionListener startPauseButtonListener = new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
if (thread.stopped)
{
pauseCount += (System.currentTimeMillis() - pauseStart);
thread.stopped = false;
startPauseButton.setText("暂停");
}
else
{
pauseStart = System.currentTimeMillis();
thread.stopped = true;
startPauseButton.setText("继续");
}
}
};
private ActionListener resetButtonListener = new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
pauseStart = programStart;
pauseCount = 0;
thread.stopped = true;
label.setText(INITIAL_LABEL_TEXT);
startPauseButton.setText("开始");
}
};
public Timer(String title) throws HeadlessException
{
super(title);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLocation(300, 300);
setResizable(false);
setupBorder();
setupLabel();
setupButtonsPanel();
startPauseButton.addActionListener(startPauseButtonListener);
resetButton.addActionListener(resetButtonListener);
thread.start(); // 计数线程一直就运行着
}
// 为窗体面板添加边框
private void setupBorder()
{
JPanel contentPane = new JPanel(new BorderLayout());
contentPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
this.setContentPane(contentPane);
}
// 配置按钮
private void setupButtonsPanel()
{
JPanel panel = new JPanel(new FlowLayout());
panel.add(startPauseButton);
panel.add(resetButton);
add(panel, BorderLayout.SOUTH);
}
// 配置标签
private void setupLabel()
{
label.setHorizontalAlignment(SwingConstants.CENTER);
label.setFont(new Font(label.getFont()
.getName(), label.getFont()
.getStyle(), 40));
this.add(label, BorderLayout.CENTER);
}
// 程序入口
public static void main(String[] args)
{
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
}
catch (Exception e)
{
e.printStackTrace();
}
Timer frame = new Timer("计时器");
frame.pack();
frame.setVisible(true);
}
private class CountingThread extends Thread
{
public boolean stopped = true;
private CountingThread()
{
setDaemon(true);
}
@Override
public void run()
{
while (true)
{
if (!stopped)
{
long elapsed = System.currentTimeMillis() - programStart - pauseCount;
label.setText(format(elapsed));
}
try
{
sleep(1); // 1毫秒更新一次显示
}
catch (InterruptedException e)
{
e.printStackTrace();
System.exit(1);
}
}
}
// 将毫秒数格式化
private String format(long elapsed)
{
int hour, minute, second, milli;
milli = (int)(elapsed % 1000);
elapsed = elapsed / 1000;
second = (int)(elapsed % 60);
elapsed = elapsed / 60;
minute = (int)(elapsed % 60);
elapsed = elapsed / 60;
hour = (int)(elapsed % 60);
return String.format("%02d:%02d:%02d %03d", hour, minute, second, milli);
}
}
}java计时器功能就这样就能实现了，实现java计时器功能是在开发工程中经常遇见的，并且也是一个简单的java开发项目，而本篇文章能够给大家带来参考价值，希望能够帮助到大家!最后大家如果想要了解更多java入门知识，敬请关注奇Q工具网。
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