使用了简单的JFrame窗口，在窗口中添加菜单，菜单选项，点击鼠标右键出现右键菜单，用io流将输入文本域的内容保存。并设置热键alt+x为退出的热键

public class MyNotepad extends JFrame{

//菜单栏

private JMenuBar jmb = new JMenuBar();

//菜单

private JMenu jmFile = new JMenu("文件(F)");

private JMenu jmEdit = new JMenu("编辑(E)");

private JMenu jmFormat = new JMenu("格式(O)");

private JMenu jmFind = new JMenu("查看(V)");

private JMenu jmHelp = new JMenu("帮助(H)");

//菜单项

private JMenuItem jmiNew = new JMenuItem("新建");

private JMenuItem jmiOpen = new JMenuItem("打开");

private JMenuItem jmiSave = new JMenuItem("保存");

private JMenuItem jmiOther = new JMenuItem("另存为");

private JMenuItem jmiExit = new JMenuItem("退出(X)");

private JCheckBoxMenuItem jmiAutoLine = new JCheckBoxMenuItem("自动换行");

private JMenuItem jmiFont = new JMenuItem("字体");

private JFileChooser jfc = new JFileChooser();

private JTextArea jta = new JTextArea();

private JScrollPane jsp = new JScrollPane(jta);

//上下文菜单

private JPopupMenu jpm = new JPopupMenu();

private JMenuItem jmiCopy = new JMenuItem("复制");

private JMenuItem jmiPaste = new JMenuItem("粘贴");

public MyNotepad() {

this.setTitle("记事本");

this.setSize(600,400);

this.setLocationRelativeTo(null);

this.setDefaultCloseOperation(EXIT_ON_CLOSE);

this.add(jmb,BorderLayout.NORTH);

jmb.add(jmFile);

jmb.add(jmEdit);

jmb.add(jmFormat);

jmb.add(jmFind);

jmb.add(jmHelp);

jmFile.add(jmiNew);

jmFile.add(jmiOpen);

jmFile.add(jmiSave);

jmFile.add(jmiOther);

jmFile.addSeparator();

jmFile.add(jmiExit);

jmFormat.add(jmiAutoLine);

jmFormat.add(jmiFont);

//上下文菜单

jpm.add(jmiCopy);

jpm.add(jmiPaste);

jpm.add(jmFile);

jta.addMouseListener(new MouseAdapter() {

public void mouseClicked(MouseEvent e) {

if(e.getButton() == 3){

jpm.show(jta, e.getX(), e.getY());

}

}

});

//文本域自动换行

this.add(jsp,BorderLayout.CENTER);

jmiAutoLine.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

boolean selected = jmiAutoLine.isSelected();

if(selected){

jta.setLineWrap(true);

}else{

jta.setLineWrap(false);

}

}

});

//文件新建窗口

jmiNew.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

int choose = jfc.showOpenDialog(MyNotepad.this);

switch (choose) {

case JFileChooser.APPROVE_OPTION:

System.out.println("点击了打开");

break;

case JFileChooser.CANCEL_OPTION:

System.out.println("点击了取消");

break;

}

}

});

//文件保存窗口，用随机数命名文件名随时保存进新的文件

jmiSave.addActionListener(new ActionListener() {

@Override

public void actionPerformed(ActionEvent arg0) {

Random r = new Random();

int a = r.nextInt(100);

File file = new File("D:\\桌面\\b"+"r"+"a.txt");

try {

FileOutputStream fis = new FileOutputStream(file,true);

BufferedOutputStream bis = new BufferedOutputStream(fis);

byte [] b = jta.getText().getBytes();

try {

bis.write(b);

bis.flush();

bis.close();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (FileNotFoundException e) {

e.printStackTrace();

}

}

});

jmiExit.registerKeyboardAction(new ActionListener() {

public void actionPerformed(ActionEvent e) {

System.exit(0);

}

}, KeyStroke.getKeyStroke(KeyEvent.VK_X,KeyEvent.ALT_DOWN_MASK),

JComponent.WHEN_IN_FOCUSED_WINDOW);//1.设置监听事件。2.设置热键alt+x关闭窗口3.设置触发当鼠标聚焦在窗口时

jmiExit.addActionListener(new ActionListener() {

public void actionPerformed(ActionEvent e) {

System.exit(0);

}

});

this.setVisible(true);

}

public static void main(String[] args) {

new MyNotepad();

}

}