Java语言编写记事本(代码)

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.undo.*;
import java.io.*;
public class Note extends JFrame
{UndoManager manager=new UndoManager();
 JTextArea text = new JTextArea();
 JFileChooser chooser;
 String s="新建记事本";
 File file;
 JMenuBar Mb;
 JMenu M1,M2,M3,M4;
 JMenuItem m11,m12,m13,m14,m15,m21,m22,m23,m24,m25,m32,m33,m41;
 JCheckBoxMenuItem m31=new JCheckBoxMenuItem("自动换行",true);
  /**文件格式过滤器**/
  private   class filter extends javax.swing.filechooser.FileFilter
  {public boolean accept(File file)
	 {String name=file.getName();
      name.toLowerCase();
      if(name.endsWith(".txt")||file.isDirectory())
		  return true;
	  else return false;
     }
   public String getDescription()
	  {return ".txt";
      }
  }
   /**将菜单项JMenuItem添加到菜单JMenu**/
 public JMenuItem AddItem(String name,JMenu menu)
  {JMenuItem MI=new JMenuItem(name);
   menu.add(MI);
   return MI;
  }
  /**将菜单JMenu添加到菜栏JMenuBar**/
 public JMenu AddBar(String name,JMenuBar mb)
  {JMenu Mb=new JMenu(name);
   mb.add(Mb);
   return Mb;
  }

 Note()
  {setTitle(s);
   setBounds(200,200,500,500);
   Mb=new JMenuBar();
   this.setJMenuBar(Mb);
   text.getDocument().addUndoableEditListener(manager);
   text.setFont(new Font("宋体",Font.PLAIN,14));
   text.setCaretColor(Color.RED);//光标颜色
   text.setSelectedTextColor(Color.RED);//选中字体颜色
   text.setSelectionColor(Color.GREEN);//选中背景颜色
   text.setLineWrap(true); //是否换行
   text.setWrapStyleWord(true);  //是否单词边界换行（即有空白）
   text.setMargin(new Insets(3, 5, 3, 5));//文本区与边框的间距，四个参数分别为上、左、下、右
   text.setDragEnabled(true); //开启或关闭自动拖动处理
   add(new JScrollPane(text,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED));

   M1=this.AddBar("文件",Mb);
   M2=this.AddBar("编辑",Mb);
   M3=this.AddBar("格式",Mb);
   M4=this.AddBar("帮助",Mb);
     /*新建选项*/
   m11=this.AddItem("新建",M1);
   m11.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent event)
	   {text.setText("");
       }
   });
     /*打开选项*/
   m12=this.AddItem("打开",M1);
   m12.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent event)
	 {try{chooser=new JFileChooser();
      chooser.setCurrentDirectory(new File("."));
      chooser.setFileFilter(new filter());
      chooser.showOpenDialog(null);
	  file=chooser.getSelectedFile();
	  s=file.getName();
	  setTitle(s);
	  int length=(int)file.length();
	  FileReader fr=new FileReader(file);
      char[] ch=new char[length];
	  fr.read(ch);
	  s=new String(ch);
      text.setText(s.trim());}
	  catch(Exception e){JOptionPane.showMessageDialog(null,e);}
     }
   });
      /*保存选项*/
   m13=this.AddItem("保存",M1);
   m13.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent event)
	 { if(file==null)try{
	   chooser=new JFileChooser();
	   chooser.setCurrentDirectory(new File("."));
       s=JOptionPane.showInputDialog("请输入文件名：")+".txt";
       chooser.setSelectedFile(new File(s));
	   chooser.setFileFilter(new filter());
	   int yn=chooser.showSaveDialog(null);
	   if(yn==chooser.APPROVE_OPTION)
	   {   file=new File(chooser.getCurrentDirectory(),s);
		   file.createNewFile();
		   FileWriter fw=new FileWriter(file);
	       fw.write(text.getText());
	       fw.close();
       }
      }
	  catch(Exception e){JOptionPane.showMessageDialog(null,e);}
	  else try{
	  FileWriter fw=new FileWriter(file);
	  fw.write(text.getText());
	  fw.close();
	  }
	  catch(Exception e){JOptionPane.showMessageDialog(null,e);}
     }
   });
      /*另存为选项*/
   m14=this.AddItem("另存为",M1);
   m14.addActionListener(new ActionListener(){
   public void actionPerformed(ActionEvent event)
	   {chooser=new JFileChooser();
        chooser.setCurrentDirectory(new File("."));
	   try{
       if(file==null) s=JOptionPane.showInputDialog("请输入文件名：")+".txt";
       else s=file.getName();
	   chooser.setSelectedFile(new File(s));
	   chooser.setFileFilter(new filter());
	   int yn=chooser.showSaveDialog(null);
	   if(yn==chooser.APPROVE_OPTION)
	   {   if(file!=null) file.delete();
		   file=new File(chooser.getCurrentDirectory(),s);
		   file.createNewFile();
		   FileWriter fw=new FileWriter(file);
	       fw.write(text.getText());
	       fw.close();
       }
		}
	  catch(Exception e){JOptionPane.showMessageDialog(null,e);}
       }
   });
     
   M1.addSeparator(); //横杆
     /*退出选项*/
   m15=this.AddItem("退出",M1);
   m15.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent event) {
    System.exit(0);
   }
  });
     /*撤消选项*/
  m21=this.AddItem("撤消",M2);
  m21.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	 {if(manager.canUndo())
	     manager.undo();
     }
  });
     /*剪切选项*/
  M2.addSeparator();
  m22=this.AddItem("剪切",M2);
  m22.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	 {text.cut();
     }
  });
    /*复制选项*/
  m23=this.AddItem("复制",M2);
  m23.addActionListener(new ActionListener(){
	public void actionPerformed(ActionEvent event)
	{text.copy();
	}
  });
    /*粘贴选项*/
  m24=this.AddItem("粘贴",M2);
  m24.addActionListener(new ActionListener(){
	public void actionPerformed(ActionEvent event)
	{	text.paste();
	}
  });
    /*删除选项*/
  m25=this.AddItem("删除",M2);
  m25.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	 {text.replaceRange("",text.getSelectionStart(),text.getSelectionEnd());
     }
  });
    /*自动换行选项*/
  M3.add(m31);
  m31.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	{if(m31.getState())
	  text.setLineWrap(true);
     else text.setLineWrap(false);
    }
  });
    /*字体格式设置选项*/
  m32=this.AddItem("字体选择",M3);
  m32.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	{ GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
  JList fontNames = new JList(ge.getAvailableFontFamilyNames());
  int response = JOptionPane.showConfirmDialog(null, new JScrollPane(fontNames),"请选择字体",JOptionPane.OK_CANCEL_OPTION);
  Object selectedFont = fontNames.getSelectedValue();
    if (response == JOptionPane.OK_OPTION && selectedFont != null)
      text.setFont(new Font(fontNames.getSelectedValue().toString(),Font.PLAIN,20));
    }
  });
    /*字体颜色设置选项*/
  m33=this.AddItem("字体颜色",M3);
  m33.addActionListener(
    new ActionListener(){
     public void actionPerformed(ActionEvent event){
      Color color = JColorChooser.showDialog(null, "文字颜色选择", Color.WHITE);
      text.setForeground(color);
     }
    }
    );

  m41=this.AddItem("关于记事本",M4);
  m41.addActionListener(new ActionListener(){
  public void actionPerformed(ActionEvent event)
	{JOptionPane.showMessageDialog(null,"记事本\n开发语言：JAVA\n开发者：林岗则","关于",JOptionPane.PLAIN_MESSAGE);
    }
  });
   setResizable(true); //窗体是否可变
   setVisible(true);   //窗体是否可见
   setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }

 public static void main(String args[])
  {Note n=new Note();
  }
}