Java:如何将JMenu添加到JPanel或创建下拉按钮？

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

public class JMenuExample {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGUI());
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("JMenu Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(new Dimension(400, 200));

        JPanel panel = new JPanel();
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Menu");

        JMenuItem menuItem1 = new JMenuItem("Option 1");
        JMenuItem menuItem2 = new JMenuItem("Option 2");
        JMenuItem menuItem3 = new JMenuItem("Option 3");

        menu.add(menuItem1);
        menu.add(menuItem2);
        menu.add(menuItem3);

        menuBar.add(menu);

        // 创建一个按钮，点击后显示下拉菜单
        JButton button = new JButton("Click me");
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JPopupMenu popupMenu = new JPopupMenu();
                popupMenu.add(menu);
                popupMenu.show(button, 0, button.getHeight());
            }
        });

        panel.add(button);
        frame.setContentPane(panel);
        frame.setJMenuBar(menuBar);
        frame.setVisible(true);
    }
}