JAVA记事本问题

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.Calendar;
public class MyNoteBook extends JFrame implements ActionListener
{
    String title="ERROR MESSAGE";
    
    int type=JOptionPane.ERROR_MESSAGE;
    
    static String Path;
    
  public MyNoteBook() 
  {
    final JFrame frame = new JFrame("我的记事本");
    
    final JTextArea text=new JTextArea();
    
    frame.setSize(600, 500);
    
    frame.addWindowListener(new WindowAdapter()
    {
        public void windowClosing(WindowEvent e)
        {
             System.exit(0);
        }
    });
    
    JPanel panel=new JPanel();
    
    panel.setLayout(new GridLayout(1,1));
    
    panel.add(new JScrollPane(text));
    
    frame.getContentPane().add(panel);
    
    JMenuBar Mbar = new JMenuBar();
    
    frame.setJMenuBar(Mbar);
    
    JMenu jfile = new JMenu("文件(F)", true);
    
    JMenu jedit = new JMenu("编辑(E)", true);
    
    JMenu jmode = new JMenu("格式(O)", true);
    
    JMenu jhelp = new JMenu("帮助(H)", true);
    
    jfile.setMnemonic('F');
    
    jedit.setMnemonic('E');
    
    jmode.setMnemonic('O');
    
    jhelp.setMnemonic('H');
    
    Mbar.add(jfile);
    
    Mbar.add(jedit);
    
    Mbar.add(jmode);
    
    Mbar.add(jhelp);
    
    
    JMenuItem jnew = new JMenuItem("新建");
    jnew.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
              text.setText(" ");
        }
    });
    jnew.setMnemonic('N');
    jnew.setAccelerator( KeyStroke.getKeyStroke('N',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jopen = new JMenuItem("打开");
    jopen.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
             JFileChooser openfile=new JFileChooser();
             openfile.setDialogTitle("打开文件");
             openfile.setApproveButtonText("打开");
             openfile.showOpenDialog(frame);
             File file=openfile.getSelectedFile();
             FileInputStream inputfile=null;
             String message="The file not Found";
            try
            {
              inputfile=new FileInputStream(file);
            }
             catch(FileNotFoundException fe) 
             {       
             JOptionPane.showMessageDialog(frame,message,title,type);
             }
             int readbytes;
             String message1="read file error";
             try
             {
                while((readbytes=inputfile.read())!=-1)
                {
                   text.append(String.valueOf((char)readbytes));   
                }
             }
             catch(IOException ioe)
             {
               JOptionPane.showMessageDialog(frame,message1,title,type);  
             }
             String closemessage="close stream error";
             try{
                     inputfile.close();
             }
             catch(IOException ioe)
             {
               JOptionPane.showMessageDialog(frame,closemessage,title,type);   
             } 
        }
    });
    jopen.setMnemonic('O');
    jopen.setAccelerator(KeyStroke.getKeyStroke('O',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jsave = new JMenuItem("保存");
    jsave.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
           JFileChooser savefile=new JFileChooser();
           savefile.setApproveButtonText("保存"); 
           savefile.setDialogTitle("保存文件"); 
           savefile.showSaveDialog(frame);
           File filesa=savefile.getSelectedFile();
           String messagef="File not Found";
           FileOutputStream outputfile=null;
           try
           {
             outputfile=new FileOutputStream(filesa);
           }
           catch(FileNotFoundException fe) 
           {       
             JOptionPane.showMessageDialog(frame,messagef,title,type);
           }
           String filecontent=text.getText();
           String wrmessage="write error";
           try
           {
              outputfile.write(filecontent.getBytes());
           }
           catch(IOException ioe)
           {
            JOptionPane.showMessageDialog(frame,wrmessage,title,type);   
           } 
           String cmessage="close stream error";
           try
           {
               outputfile.close();
           }
           catch(IOException ioe)
           {
               JOptionPane.showMessageDialog(frame,cmessage,title,type);
           }
        }
    });
    jsave.setMnemonic('S');
    jsave.setAccelerator(KeyStroke.getKeyStroke('S',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jothersava = new JMenuItem("另存为...");
    jothersava.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
           
        }
    });
    
    JMenuItem jquite = new JMenuItem("退出");
    jquite.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
            /*int i=JOptionPane.showConfirmDialog(this,"确定要退出吗?","关闭",JOptionPane.YES_NO_OPTION);
            if(i==JOptionPane.YES_OPTION)*/
            System.exit(0);
        }
    });
    jquite.setMnemonic('Q');
    jquite.setAccelerator(KeyStroke.getKeyStroke('Q',java.awt.Event.CTRL_MASK,true));
    
     
    JMenuItem jcut = new JMenuItem("剪切");
    jcut.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
              text.cut();
        }
    });
    jcut.setMnemonic('C');
    jcut.setAccelerator(KeyStroke.getKeyStroke('C',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jcopy = new JMenuItem("复制");
    jcopy.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
              text.copy();
        }
    });
    jcopy.setMnemonic('o');
    jcopy.setAccelerator(KeyStroke.getKeyStroke('O',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jpaste = new JMenuItem("粘贴");
    jpaste.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
              text.paste();
        }
    });
    jpaste.setMnemonic('P');
    jpaste.setAccelerator(KeyStroke.getKeyStroke('P',java.awt.Event.CTRL_MASK,true));
    
     JMenuItem jallselect = new JMenuItem("全选");
    jallselect.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
              text.selectAll();
        }
    });
    jallselect.setMnemonic('A');
    jallselect.setAccelerator(KeyStroke.getKeyStroke('A',java.awt.Event.CTRL_MASK,true));
    
    JMenuItem jtimeDate = new JMenuItem("插入日期时间");
    jtimeDate.addActionListener(new ActionListener()
    {
        public void actionPerformed(ActionEvent e)
        {
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy'年'MM'月'dd'日'+HH:mm:ss");
            Calendar today = Calendar.getInstance();
            String timeDate = dateFormat.format(today.getTime());
            text.append(timeDate);
        }
     });
    jtimeDate.setMnemonic('D');
    jtimeDate.setAccelerator(KeyStroke.getKeyStroke('D',java.awt.Event.CTRL_MASK,true));
写不下了，换到下个提问