jj.java

用Java编的文本编辑器。 可以一看。

import java.io.*; 
import java.lang.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.awt.datatransfer.*; 
public class NotePad extends Frame implements ActionListener 
{ 
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"); 
Menu aboutmenu=new Menu("About"); 
MenuItem info=new MenuItem("About NotePad"); 
String fileName="NoName";//设置默认的文件名 
Toolkit toolkit=Toolkit.getDefaultToolkit(); 
Clipboard clipboard=toolkit.getSystemClipboard();//剪贴板对象 
private FileDialog openFileDialog=new FileDialog(this,"Open File",FileDialog.LOAD); 
private FileDialog saveAsFileDialog=new FileDialog(this,"Save File As",FileDialog.SAVE); 
public NotePad() 
{ 
setTitle("NotePad"); 
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.add(copyitem); 
editmenu.addSeparator(); 
editmenu.add(cutitem); 
editmenu.add(pasteitem); 
menubar.add(filemenu); 
menubar.add(editmenu); 
menubar.add(aboutmenu); 
aboutmenu.add(info); 
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) 
{ 
Object eventSource=e.getSource();//利用事件源判断被单击的菜单项 
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==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) 
{ 
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) 
{ 
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"); 
} 
} 
public static void main(String[] args) 
{ 
Frame frame=new NotePad(); 
frame.show(); 
} 
}