如何从Java Swing计时器计算经过的时间

import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;

public class TimerExample {
    private static final SimpleDateFormat TIME_FORMAT = new SimpleDateFormat("HH:mm:ss");

    public static void main(String[] args) {
        JFrame frame = new JFrame("Timer Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        JLabel timeLabel = new JLabel("00:00:00");
        frame.add(timeLabel);

        Timer timer = new Timer(1000, new ActionListener() {
            private final Date startTime = new Date();

            @Override
            public void actionPerformed(ActionEvent e) {
                Date currentTime = new Date();
                long elapsedTime = currentTime.getTime() - startTime.getTime();

                String formattedTime = formatTime(elapsedTime);
                timeLabel.setText(formattedTime);
            }
        });
        timer.start();

        frame.pack();
        frame.setVisible(true);
    }

    private static String formatTime(long time) {
        long hours = time / (60 * 60 * 1000);
        long minutes = (time % (60 * 60 * 1000)) / (60 * 1000);
        long seconds = (time % (60 * 1000)) / 1000;

        return String.format("%02d:%02d:%02d", hours, minutes, seconds);
    }
}