import java.awt.*;import java.io.*;import java.awt.datatransfer.*;import java.awt.event.*;public class Main extends Frame implements ActionListener {        private static final long serialVersionUID = 1L;TextArea textArea = new TextArea();   MenuBar menuBar = new MenuBar();   Menu fileMenu = new Menu("File");   MenuItem newItem = new MenuItem("New");   MenuItem openItem = new MenuItem("Open");   MenuItem saveItem = new MenuItem("Save");   MenuItem saveAsItem = new MenuItem("Save As");   MenuItem exitItem = new MenuItem("Exit");   Menu editMenu = new Menu("Edit");   MenuItem selectItem = new MenuItem("Select All");   MenuItem copyItem = new MenuItem("Copy");   MenuItem cutItem = new MenuItem("Cut");   MenuItem pasteItem = new MenuItem("Paste");   String fileName = null;   Toolkit toolKit=Toolkit.getDefaultToolkit();   Clipboard clipBoard=toolKit.getSystemClipboard();       private FileDialog openFileDialog = new FileDialog(this,"Open File",FileDialog.LOAD);    private FileDialog saveAsFileDialog = new FileDialog(this,"Save File As",FileDialog.SAVE);  public Main(){    setTitle("记事本程序-by Jackbase");    setFont(new Font("Times New Roman",Font.PLAIN,12));    setBackground(Color.white);    setSize(400,300);    fileMenu.add(newItem);    fileMenu.add(openItem);    fileMenu.addSeparator();    fileMenu.add(saveItem);    fileMenu.add(saveAsItem);    fileMenu.addSeparator();    fileMenu.add(exitItem);    editMenu.add(selectItem);    editMenu.addSeparator();    editMenu.add(copyItem);    editMenu.add(cutItem);    editMenu.add(pasteItem);    menuBar.add(fileMenu);    menuBar.add(editMenu);    setMenuBar(menuBar);    add(textArea);    addWindowListener(new WindowAdapter(){                      public void windowClosing(WindowEvent e){                          System.exit(0);                        }                      });    newItem.addActionListener(this);    openItem.addActionListener(this);    saveItem.addActionListener(this);    saveAsItem.addActionListener(this);    exitItem.addActionListener(this);    selectItem.addActionListener(this);    copyItem.addActionListener(this);    cutItem.addActionListener(this);    pasteItem.addActionListener(this);  }  public void actionPerformed(ActionEvent e) {  //监听事件    Object eventSource = e.getSource();    if(eventSource == newItem){      textArea.setText("");    }else if(eventSource == openItem){      openFileDialog.show();      fileName = openFileDialog.getDirectory()+openFileDialog.getFile();      if(fileName != null)        readFile(fileName);    }else if (eventSource == saveItem){      if(fileName != null)        writeFile(fileName);    }else if(eventSource == saveAsItem){      saveAsFileDialog.show();      fileName = saveAsFileDialog.getDirectory()+saveAsFileDialog.getFile();      if (fileName!= null)        writeFile(fileName);    }else if(eventSource == selectItem){       textArea.selectAll();    }else if(eventSource == copyItem){       String text=textArea.getSelectedText();       StringSelection selection=new StringSelection(text);       clipBoard.setContents(selection,null);    }else if(eventSource == cutItem){       String text=textArea.getSelectedText();       StringSelection selection=new StringSelection(text);       clipBoard.setContents(selection,null);       textArea.replaceRange("",textArea.getSelectionStart(),textArea.getSelectionEnd());    }else if(eventSource == pasteItem){       Transferable contents=clipBoard.getContents(this);       if(contents==null) return;       String text;       text="";       try{            text=(String)contents.getTransferData(DataFlavor.stringFlavor);        }catch(Exception exception){        }       textArea.replaceRange(text,textArea.getSelectionStart(),textArea.getSelectionEnd());    }else if(eventSource == exitItem){      System.exit(0);    }  }  public void readFile(String fileName){ //读取文件处理    try{      File file = new File(fileName);      FileReader readIn = new FileReader(file);      int size = (int)file.length();      int charsRead = 0;      char[] content = new char[size];      while(readIn.ready())        charsRead += readIn.read(content, charsRead, size - charsRead);      readIn.close();      textArea.setText(new String(content, 0, charsRead));    }    catch(IOException e){      System.out.println("Error opening file");    }  }  public void writeFile(String fileName){  //写入文件处理    try{      File file = new File (fileName);      FileWriter writeOut = new FileWriter(file);      writeOut.write(textArea.getText());      writeOut.close();    }    catch(IOException e){      System.out.println("Error writing file");    }  }    @SuppressWarnings("deprecation")        public static void main(String[] args){      Frame frame = new Main(); //创建对象      frame.show();   //是对象显示   }}