Java Swing里面JMenu快捷键怎么设置？

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

public class SwingMenu implements ActionListener {
public void actionPerformed(ActionEvent e) {
String lab = ((JMenuItem) e.getSource()).getText();
System.out.println("label = " + lab);
if (lab.equals("Exit")) {
System.exit(0);
}
}

public static void main(String args[]) {
JFrame f = new JFrame("testing");
JMenu m = new JMenu("File");
m.setMnemonic(KeyEvent.VK_F);
SwingMenu acl = new SwingMenu();

JMenuItem mi1 = new JMenuItem("Open");
mi1.setMnemonic(KeyEvent.VK_O);
mi1.addActionListener(acl);
m.add(mi1);

KeyStroke ms2 = KeyStroke.getKeyStroke(KeyEvent.VK_S,InputEvent.CTRL_MASK);
JMenuItem mi2 = new JMenuItem("Save");
mi2.setMnemonic(KeyEvent.VK_S);
mi2.setAccelerator(ms2);
mi2.addActionListener(acl);
m.add(mi2);

KeyStroke ms3 = KeyStroke.getKeyStroke(KeyEvent.VK_E,
InputEvent.CTRL_MASK);
JMenuItem mi3 = new JMenuItem("Exit");
mi3.setMnemonic(KeyEvent.VK_E);
mi3.setAccelerator(ms3);
mi3.addActionListener(acl);
m.add(mi3);

KeyStroke ms4 = KeyStroke.getKeyStroke('x');
JMenuItem mi4 = new JMenuItem("Close");
mi4.setMnemonic(KeyEvent.VK_N);
mi4.setAccelerator(ms4);
mi4.addActionListener(acl);
m.add(mi4);

JMenuBar mb = new JMenuBar();
mb.add(m);
f.setJMenuBar(mb);
f.setSize(200, 200);
f.setVisible(true);
}
}

/**
/*KeyStroke ms4 = KeyStroke.getKeyStroke('x'); 单快捷键

/*KeyStroke ms3 = KeyStroke.getKeyStroke(KeyEvent.VK_E,
InputEvent.CTRL_MASK);组合快捷键

具体键值可能还需要查一下，我也是网上搜的。看看吧。