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;

//第一种比较推荐：

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);

}

}

import java.awt.Dimension;

import java.text.SimpleDateFormat;

import java.util.Calendar;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

//第二种

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();

}

}

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;

//第三种：多国时钟实现

public class WorldTimeFrame extends JFrame

{

/**

*

*/

private static final long serialVersionUID = 4782486524987801209L;

private String time;

private JPanel timePanel;

private TimeZone timeZone;//时区

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();

}

}