Java Swing循环进度条不起作用

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class ProgressBarExample {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JFrame frame = new JFrame("Progress Bar Example");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(400, 200);

            JProgressBar progressBar = new JProgressBar(0, 100);
            progressBar.setValue(0);
            progressBar.setStringPainted(true);

            JButton startButton = new JButton("Start");
            startButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    Thread thread = new Thread(() -> {
                        for (int i = 0; i <= 100; i++) {
                            try {
                                Thread.sleep(50);
                                progressBar.setValue(i);
                            } catch (InterruptedException ex) {
                                ex.printStackTrace();
                            }
                        }
                    });
                    thread.start();
                }
            });

            frame.getContentPane().setLayout(new FlowLayout());
            frame.getContentPane().add(progressBar);
            frame.getContentPane().add(startButton);

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