简单记事本java源码实例

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

   }

}