簡單記事本java源碼實例

本文實例講述了簡單記事本java實作程式碼。分享給大家供大家參考。具體如下：

完整程式碼如下：
複製程式碼如下: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("記事本程式-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) { //監聽事件
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){ //讀取檔案處理
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){ //寫入檔案處理
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(); //建立對象
frame.show(); //是物件顯示
}
}

運行結果如下圖所示：

希望本文所述對大家的java程式設計有幫助。