我同意您应该考虑按照Anh Pham使用“ Java”计时器，但是实际上，有几个可用的Timer类，并且出于您的目的，Swing
Timer不是Anh建议的java.util.Timer会适合您的目的。最好。
至于您的问题，实际上只不过是一个简单的引用问题。为带有标签的类提供一个公共方法，例如
setCountDownLabelText(Stringtext)，然后从保存计时器的类中调用该方法。您需要使用另一个类中的计时器JLabel来引用GUI类。
例如：
import java.awt.BorderLayout;import java.awt.CardLayout;import java.awt.Color;import java.awt.Dimension;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.*;public class Welcome extends JPanel { private static final String INTRO = "intro"; private static final String USED_BEFORE = "used before"; private CardLayout cardLayout = new CardLayout(); private JLabel countDownLabel = new JLabel("", SwingConstants.CENTER); public Welcome() { JPanel introSouthPanel = new JPanel(); introSouthPanel.add(new JLabel("Status:")); introSouthPanel.add(countDownLabel); JPanel introPanel = new JPanel(); introPanel.setPreferredSize(new Dimension(400, 300)); introPanel.setLayout(new BorderLayout()); introPanel.add(new JLabel("WELCOME", SwingConstants.CENTER), BorderLayout.CENTER); introPanel.add(introSouthPanel, BorderLayout.SOUTH); JPanel usedBeforePanel = new JPanel(new BorderLayout()); usedBeforePanel.setBackground(Color.pink); usedBeforePanel.add(new JLabel("Used Before", SwingConstants.CENTER)); setLayout(cardLayout); add(introPanel, INTRO); add(usedBeforePanel, USED_BEFORE); new HurdlerTimer(this).start(); } private static void createAndShowUI() { Jframe frame = new Jframe("Welcome"); frame.getContentPane().add(new Welcome()); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); frame.pack(); frame.setLocationRelativeTo(null); frame.setVisible(true); } public static void main(String[] args) { java.awt.EventQueue.invokeLater(new Runnable() { public void run() { createAndShowUI(); } }); } public void setCountDownLabelText(String text) { countDownLabel.setText(text); } public void showNextPanel() { cardLayout.next(this); }}class HurdlerTimer { private static final int TIMER_PERIOD = 1000; protected static final int MAX_COUNT = 10; private Welcome welcome; // holds a reference to the Welcome class private int count; public HurdlerTimer(Welcome welcome) { this.welcome = welcome; // initializes the reference to the Welcome class. String text = "(" + (MAX_COUNT - count) + ") seconds left"; welcome.setCountDownLabelText(text); } public void start() { new Timer(TIMER_PERIOD, new ActionListener() { @Override public void actionPerformed(ActionEvent e) { if (count < MAX_COUNT) { count++; String text = "(" + (MAX_COUNT - count) + ") seconds left"; welcome.setCountDownLabelText(text); // uses the reference to Welcome } else { ((Timer) e.getSource()).stop(); welcome.showNextPanel(); } } }).start(); }}
