Java实现时间动态显示方法汇总

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这篇文章主要介绍了Java实现时间动态显示方法汇总,很实用的功能,需要的朋友可以参考下

本文所述实例可以实现Java在界面上动态的显示时间。具体实现方法汇总如下：

1.方法一用TimerTask：

利用java.util.Timer和java.util.TimerTask来做动态更新，毕竟每次更新可以看作是计时1秒发生一次。
代码如下：

import java.awt.Dimension;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
 * This class is a simple JFrame implementation to explain how to
 * display time dynamically on the JSwing-based interface.
 * @author Edison
 *
 */
public class TimeFrame extends JFrame
{
 /*
 * Variables 
 */
 private JPanel timePanel;
 private JLabel timeLabel;
 private JLabel displayArea;
 private String DEFAULT_TIME_FORMAT = "HH:mm:ss";
 private String time;
 private int ONE_SECOND = 1000;
  
 public TimeFrame()
 {
 timePanel = new JPanel();
 timeLabel = new JLabel("CurrentTime: ");
 displayArea = new JLabel();
  
 configTimeArea();
  
 timePanel.add(timeLabel);
 timePanel.add(displayArea);
 this.add(timePanel);
 this.setDefaultCloseOperation(EXIT_ON_CLOSE);
 this.setSize(new Dimension(200,70));
 this.setLocationRelativeTo(null);
 }
  
 /**
 * This method creates a timer task to update the time per second
 */
 private void configTimeArea() {
 Timer tmr = new Timer();
 tmr.scheduleAtFixedRate(new JLabelTimerTask(),new Date(), ONE_SECOND);
 }
  
 /**
 * Timer task to update the time display area
 *
 */
 protected class JLabelTimerTask extends TimerTask{
 SimpleDateFormat dateFormatter = new SimpleDateFormat(DEFAULT_TIME_FORMAT);
 @Override
 public void run() {
  time = dateFormatter.format(Calendar.getInstance().getTime());
  displayArea.setText(time);
 }
 }
  
 public static void main(String arg[])
 {
 TimeFrame timeFrame=new TimeFrame();
 timeFrame.setVisible(true); 
 } 
}/* 何问起 hovertree.com */

继承TimerTask来创建一个自定义的task，获取当前时间，更新displayArea.
然后创建一个timer的实例，每1秒执行一次timertask。由于用schedule可能会有时间误差产生，所以直接调用精度更高的scheduleAtFixedRate的。

2. 方法二：利用线程：

这个就比较简单了。具体代码如下：

import java.awt.Dimension;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
/**
 * This class is a simple JFrame implementation to explain how to
 * display time dynamically on the JSwing-based interface.
 * @author Edison
 *
 */
public class DTimeFrame2 extends JFrame implements Runnable{
 private JFrame frame;
 private JPanel timePanel;
 private JLabel timeLabel;
 private JLabel displayArea;
 private String DEFAULT_TIME_FORMAT = "HH:mm:ss";
 private int ONE_SECOND = 1000;
  
 public DTimeFrame2()
 {
 timePanel = new JPanel();
 timeLabel = new JLabel("CurrentTime: ");
 displayArea = new JLabel();
  
 timePanel.add(timeLabel);
 timePanel.add(displayArea);
 this.add(timePanel);
 this.setDefaultCloseOperation(EXIT_ON_CLOSE);
 this.setSize(new Dimension(200,70));
 this.setLocationRelativeTo(null);
 }
 public void run()
 {
 while(true)
 {
  SimpleDateFormat dateFormatter = new SimpleDateFormat(DEFAULT_TIME_FORMAT);
  displayArea.setText(dateFormatter.format(
     Calendar.getInstance().getTime()));
  try
  {
  Thread.sleep(ONE_SECOND); 
  }
  catch(Exception e)
  {
  displayArea.setText("Error!!!");
  }
 } 
 } 
  
 public static void main(String arg[])
 {
 DTimeFrame2 df2=new DTimeFrame2();
 df2.setVisible(true);
  
 Thread thread1=new Thread(df2);
 thread1.start(); 
 } 
}
/* hwq2.com */

比较：

个人倾向于方法一，因为Timer是可以被多个TimerTask共用，而产生一个线程，会增加多线程的维护复杂度。

注意如下代码：

jFrame.setDefaultCloseOperation(); // 给关闭按钮增加特定行为
jFrame.setLocationRelativeTo(null); // 让Frame一出来就在屏幕中间，而不是左上方。

将上面方法一稍微一修改，就可以显示多国时间。代码如下：

import java.awt.BorderLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; import java.util.Locale; import java.util.TimeZone; import java.util.Timer; import java.util.TimerTask; import javax.swing.DefaultComboBoxModel; import javax.swing.JComboBox; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPanel; /** * A simple world clock * @author Edison * */ public class WorldTimeFrame extends JFrame { /** * */ private static final long serialVersionUID = 4782486524987801209L; private String time; private JPanel timePanel; private TimeZone timeZone; private JComboBox zoneBox; private JLabel displayArea; private int ONE_SECOND = 1000; private String DEFAULT_FORMAT = "EEE d MMM, HH:mm:ss"; public WorldTimeFrame() { zoneBox = new JComboBox(); timePanel = new JPanel(); displayArea = new JLabel(); timeZone = TimeZone.getDefault(); zoneBox.setModel(new DefaultComboBoxModel(TimeZone.getAvailableIDs())); zoneBox.addActionListener(new ActionListener(){ @Override public void actionPerformed(ActionEvent e) { updateTimeZone(TimeZone.getTimeZone((String) zoneBox.getSelectedItem())); } }); configTimeArea(); timePanel.add(displayArea); this.setLayout(new BorderLayout()); this.add(zoneBox, BorderLayout.NORTH); this.add(timePanel, BorderLayout.CENTER); this.setLocationRelativeTo(null); this.setDefaultCloseOperation(EXIT_ON_CLOSE); this.setVisible(true); pack(); } /** * This method creates a timer task to update the time per second */ private void configTimeArea() { Timer tmr = new Timer(); tmr.scheduleAtFixedRate(new JLabelTimerTask(),new Date(), ONE_SECOND); } /** * Timer task to update the time display area * */ public class JLabelTimerTask extends TimerTask{ SimpleDateFormat dateFormatter = new SimpleDateFormat(DEFAULT_FORMAT, Locale.ENGLISH); @Override public void run() { dateFormatter.setTimeZone(timeZone); time = dateFormatter.format(Calendar.getInstance().getTime()); displayArea.setText(time); } } /** * Update the timeZone * @param newZone */ public void updateTimeZone(TimeZone newZone) { this.timeZone = newZone; } public static void main(String arg[]) { new WorldTimeFrame(); } }/* 何问起 hovertree.com */