Java 定时器类 Timer 使用方法详解编程语言

  
import java.awt.*; 
import java.awt.event.*; 
import java.text.SimpleDateFormat; 
import java.util.*; 
import java.util.Timer; 
import javax.swing.*; 
  
public class SimpleTimer extends JWindow { 
 
  
    public static void main(String[] args) { 
 
        SimpleTimer simpleTimer = new SimpleTimer(); 
        simpleTimer.pack(); 
        simpleTimer.setAlwaysOnTop(true); 
        simpleTimer.setVisible(true); 
    } 
 
    private Long startTimeMillis; 
 
    private JLabel label; 
 
    private SimpleDateFormat dateFormat; 
 
    private Timer timer; 
 
  
    public SimpleTimer() { 
 
        initDateFormat(); 
        initConponents(); 
        resetTime(); 
        updateLabelText(); 
        startTimer(); 
    } 
  
    private void initDateFormat() { 
 
        dateFormat = new SimpleDateFormat("HH:mm:ss"); 
        dateFormat.setTimeZone(TimeZone.getTimeZone("GMT")); 
    } 
 
  
    private void initConponents() { 
 
        label = new JLabel(); 
        label.setFont(new Font(label.getFont().getName(), Font.BOLD, 14)); 
        label.setOpaque(true); 
        label.setBackground(Color.black); 
        label.setForeground(Color.white); 
        label.setBorder(BorderFactory.createEmptyBorder(0, 2, 0, 2)); 
        getContentPane().add(label); 
 
        final JPopupMenu popup = new JPopupMenu(); 
        JMenuItem menuItem1 = new JMenuItem("Reset"); 
        menuItem1.addActionListener(new ActionListener() { 
 
            public void actionPerformed(ActionEvent e) { 
 
                resetTime(); 
            } 
        }); 
        popup.add(menuItem1); 
        JMenuItem menuItem2 = new JMenuItem("Exit"); 
        menuItem2.addActionListener(new ActionListener() { 
 
            public void actionPerformed(ActionEvent e) { 
 
                System.exit(0); 
            } 
        }); 
        popup.add(menuItem2); 
        label.setComponentPopupMenu(popup); 
 
        label.addMouseListener(new MouseAdapter() { 
 
            @Override 
            public void mouseClicked(MouseEvent e) { 
 
                if (e.getButton() == MouseEvent.BUTTON2 
                        && e.getClickCount() == 1) { 
                    popup.setVisible(true); 
                } 
            } 
        }); 
    } 
 
  
    private void resetTime() { 
 
        startTimeMillis = Calendar.getInstance().getTimeInMillis(); 
    } 
 
    /** 
     * ラベル更新 
     */ 
    private void updateLabelText() { 
 
        SwingUtilities.invokeLater(new Runnable() { 
 
            public void run() { 
 
                long elapsedTime = Calendar.getInstance().getTimeInMillis() 
                        - startTimeMillis; 
 
                Date date = new Date(elapsedTime); 
 
                label.setText(dateFormat.format(date)); 
            } 
        }); 
    } 
 
    /** 
     * タイマー開始 
     */ 
    private void startTimer() { 
 
        timer = new Timer(); 
        timer.schedule(new TimerTask() { 
 
            @Override 
            public void run() { 
 
                updateLabelText(); 
 
            } 
        }, 0, 1000); 
    } 
}