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

public class TestFrame extends JFrame
{
    private JMenuBar menuBar = new JMenuBar();
    private JMenu menu = new JMenu("Menu");
    private JMenuItem exitItem = new JMenuItem("EXIT");
    
    public TestFrame()
    {
        initMenuBar();
        setJMenuBar(menuBar);
        
        addWindowListener(new WindowAdapter()
            {
                public void windowClosing(WindowEvent event)
                {
                    closeWindow();
                }
            });
    }
    
    private void initMenuBar()
    {
        menuBar.add(menu);
        menu.add(exitItem);
        exitItem.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent event)
                {
                    closeWindow();
                }
            });
        exitItem.setMnemonic('E');
    }
    
    private void closeWindow()
    {
        int type = JOptionPane.showConfirmDialog(this, "是否关闭窗口？", "Question", JOptionPane.YES_NO_OPTION);
        if (type == JOptionPane.OK_OPTION)
        {
            System.exit(0);
        }
    }
    
    public static void main(String[] args)
    {
        JFrame frame = new TestFrame();
        frame.setSize(400, 300);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    }
}