自己写的记事本

import java.awt.BorderLayout;
import java.awt.FileDialog;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import gongjubao.wenjiangongju;

class jishibenmianban extends JFrame implements ActionListener
{

    JMenuBar jmb;
    JMenu jm1,jm2,jm3,jm4,jm5;
    JTextArea jta;
    
    jishibenmianban()
    {
        String[]menu1={"新建","打开","保存","退出"};
        String[]menu2={"剪切","复制","贴贴","删除","全选"};
        String[]menu3={"颜色","自动换行"};
        String[]menu4={"时间/日期"};
        String[]menu5={"关于记事本"};
        jmb=new JMenuBar();
        jm1=new JMenu("文件");
        jm2=new JMenu("编辑");
        jm3=new JMenu("格式");
        jm4=new JMenu("查看");
        jm5=new JMenu("帮助");
        
        
        jta=new JTextArea(20,60);
        
        for(String du1:menu1)
        {
            JMenuItem jmix=new JMenuItem(du1);
            jm1.add(jmix);
            jmix.addActionListener(this);
        }
        for(String du2:menu2)
        {
            JMenuItem jmix=new JMenuItem(du2);
            jm2.add(jmix);
            jmix.addActionListener(this);
        }
        for(String du3:menu3)
        {
            JMenuItem jmix=new JMenuItem(du3);
            jm3.add(jmix);
            jmix.addActionListener(this);
        }
        for(String du4:menu4)
        {
            JMenuItem jmix=new JMenuItem(du4);
            jm4.add(jmix);
            jmix.addActionListener(this);
        }
        for(String du5:menu5)
        {
            JMenuItem jmix=new JMenuItem(du5);
            jm5.add(jmix);
            jmix.addActionListener(this);
        }
        jmb.add(jm1);
        jmb.add(jm2);
        jmb.add(jm3);
        jmb.add(jm4);
        jmb.add(jm5);
        
        setJMenuBar(jmb);
        add(jta);
        setSize(800,600);
        setVisible(true);
        setLocation(600,200);
        setTitle("无标题");
        
        
    }

    public void actionPerformed(ActionEvent e) {
    
        String dedao=e.getActionCommand();
        switch(dedao)
        {
        case "新建":
            setTitle("无标题");
            jta.setText(null);
            break;
        case "打开":
            dakai();    
            break;
        case "保存":
            baocun();
            break;
        case "退出":
            System.exit(0);
            break;
        case "剪切":
            jta.cut();
            break;
        case "复制":
            jta.copy();
            break;
        case "贴贴":
            jta.paste();
            break;
        case "删除":
            jta.replaceRange("",jta.getSelectionStart(),jta.getSelectionEnd());
            break;
        case "全选":
            jta.selectAll();
            break;
        case "颜色":
            jta.setForeground(JColorChooser.showDialog(this, "颜色", null));
            break;
        case "时间/日期":
            String time=wenjiangongju.shijian();
            jta.append(time);
            break;
        case "关于记事本":
            tanchuang("记事本,为银河版权所有,电话0728-0000000");
            break;
        }
        
    }
    
    
    public void dakai()
    {
        FileDialog fd=new FileDialog(this,"打开",FileDialog.LOAD);
        fd.setVisible(true);
        String path=fd.getDirectory();
        String wenjianming=fd.getFile();
        if(fd.getDirectory()==null||fd.getFile()==null)
        {
            this.setTitle("无标题");
        }
        else{
            String xianshi=wenjiangongju.duqu(path, wenjianming);
            jta.setText(xianshi);
            this.setTitle(path+wenjianming);
            tanchuang("文件打开成功!");
        }    
    }
    
    
    public void baocun()
    {
        if(this.getTitle().equals("无标题"))
        {
        FileDialog fd=new FileDialog(this,"保存",FileDialog.SAVE);
        fd.setVisible(true);
        String path=fd.getDirectory();
        String wenjianming=fd.getFile();
        wenjiangongju.baocun(path,wenjianming,jta.getText());
        tanchuang("文件保存成功!");
        }
        else
        {
            wenjiangongju.baocun(this.getTitle(),jta.getText());
            tanchuang("文件保存成功!");
        }
        
    }
    
    public void tanchuang(String neirong)
    {
        JOptionPane.showMessageDialog(this, neirong);
    }
}

public class jishiben {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        new jishibenmianban();
    }

}