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();  }}