javax.swing.JMenuBar JMenu 以及事件响应

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

public class TestMenu {
    public static void main(String[] args) {
        MainFrame mf = new MainFrame("测试菜单");
    }
}

class MainFrame implements ActionListener {
    Container p;
    JMenuBar mb;
    final JMenu[] m = {new JMenu("文件"),
                                   new JMenu("编辑"),
                                   new JMenu("帮助")};
    final JMenuItem[][] mi = {{new JMenuItem("新建"), new JMenuItem("打开"), new JMenuItem("保存")},
                                                  {new JMenuItem("选色"), new JMenuItem("粘贴")},
                                                  {new JMenuItem("关于")}};

    public MainFrame(String title) {
        JFrame f = new JFrame(title);
        p = f.getContentPane();
        mb = new JMenuBar();
        for(int i=0; i<m.length; i++) {
            for(int j=0; j<mi[i].length; j++) {
                m[i].add(mi[i][j]);
                mi[i][j].addActionListener(this);
            }
            mb.add(m[i]);
        }
        f.setJMenuBar(mb);
        f.setBounds(200, 200, 500, 500);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if(e.getActionCommand() == "新建") {
        }
        if(e.getActionCommand() == "打开") {
            JFileChooser chooseFile = new JFileChooser();
            int returnVal = chooseFile.showOpenDialog(null);
      if(returnVal == chooseFile.APPROVE_OPTION) {
        File f = chooseFile.getSelectedFile();
        JOptionPane.showConfirmDialog(null, "你选择的文件名是："+chooseFile.getName(f),
                                      "确认",JOptionPane.ERROR_MESSAGE);
        }
        }
        if(e.getActionCommand() == "保存") {
            JFileChooser chooseFile = new JFileChooser();
            int returnVal = chooseFile.showSaveDialog(null);
      if(returnVal == chooseFile.APPROVE_OPTION) {
        File f = chooseFile.getSelectedFile();
       JOptionPane.showConfirmDialog(null,chooseFile.getName(f));
      }
        }
        if(e.getActionCommand() == "选色") {
            Color tmpColor = JColorChooser.showDialog(null, "调色板", Color.red);
        }
        if(e.getActionCommand() == "粘贴") {
        }
        if(e.getActionCommand() == "关于") {
            JOptionPane.showMessageDialog(null, (Object)"http://student.csdn.net/space.php?do=home");
        }
    }
}