notepad.java

一个记事本程序

import java.awt.*; 
import java.awt.event.*; 
import javax.swing.*; 
import javax.swing.event.*; 
import java.io.*; 

public class Notepad extends JFrame 
{ 
String openFilePath; 
String openFileName; 
String title="ERROR MESSAGE"; 
int type=JOptionPane.ERROR_MESSAGE; 

public Notepad() 
{ 

super("记事本"); 
final JTextArea text = new JTextArea(); 
text.setToolTipText("请键入内容"); 
//界面 


//退出事件 
/*this.addWindowListener(new WindowAdapter() 
{ 
public void windowClosing(WindowEvent e) 
{ 
System.exit(0); 
} 
}); */
//简单的布局 
final JPanel panel=new JPanel(); 
panel.setLayout(new GridLayout(1,1)); 
panel.add(new JScrollPane(text)); 
this.getContentPane().add(panel); 

//菜单项 
JMenuBar Mbar = new JMenuBar(); 
this.setJMenuBar(Mbar); 
JMenu file = new JMenu("文件"); 
JMenu edit = new JMenu("编辑"); 
JMenu help = new JMenu("帮助"); 
Mbar.add(file); 
Mbar.add(edit); 
Mbar.add(help); 
JMenuItem newFile = new JMenuItem("新建"); 


newFile.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
text.setText(" "); 
} 
}); 

//布局结束 
//新建文件 
newFile.setMnemonic('N'); 
newFile.setAccelerator( KeyStroke.getKeyStroke('N',java.awt.Event.CTRL_MASK,true)); 
//打开文件 
JMenuItem open = new JMenuItem("打开"); 
open.setMnemonic('O'); 
open.setAccelerator(KeyStroke.getKeyStroke('O',java.awt.Event.CTRL_MASK,true)); 
open.addActionListener(new ActionListener(){ 

public void actionPerformed(ActionEvent e){
	
JFileChooser openfile = new JFileChooser(); 
openfile.setDialogTitle("打开文件"); 
openfile.setApproveButtonText("打开"); 
openfile.showOpenDialog(panel); 
File filename = openfile.getSelectedFile(); 
StringBuffer strBF = new StringBuffer(); 
String error_message = "Error"; 
FileInputStream inputfile = null; 
try{ 
char buffer[] = new char[1024]; 
inputfile = new FileInputStream(filename); 
int len = 0; 
FileReader in = new FileReader(filename.getAbsoluteFile()); 
while((len = in.read(buffer)) != -1) 
{ 
strBF.append(buffer , 0 , len); 
} 
inputfile.close(); 
text.setText(strBF.toString()); 
String openfilename = filename.getName(); 
setTitle(openfilename); 

} 
catch(IOException ioEX) 
{ 
JOptionPane.showMessageDialog(panel,error_message,title,type); 
} 

}}); 
//保存文件 

JMenuItem save = new JMenuItem("保存"); 
save.setMnemonic('S'); 
save.setAccelerator(KeyStroke.getKeyStroke('S',java.awt.Event.CTRL_MASK,true)); 
save.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
JFileChooser savefile=new JFileChooser(); 
savefile.setApproveButtonText("保存"); 
savefile.setDialogTitle("保存文件"); 
savefile.showSaveDialog(panel); 
File filesa=savefile.getSelectedFile(); 
String file_notfound_message="找不到文件"; 
FileOutputStream outputfile=null; 
//处理异常开始 
try 
{ 
outputfile = new FileOutputStream(filesa); 
} 
catch(FileNotFoundException fe) 
{ 
JOptionPane.showMessageDialog(panel,file_notfound_message,title,type); 
} 

String filecontent=text.getText(); 
String write_error_message="写文件错误"; 
try 
{ 
outputfile.write(filecontent.getBytes()); 
} 
catch(IOException ioEx) 
{ 
JOptionPane.showMessageDialog(panel,write_error_message,title,type); 
} 
String cmessage="关闭错误"; 

try 
{ 
outputfile.close(); 
} 
catch(IOException ioEx) 
{ 
JOptionPane.showMessageDialog(panel,cmessage,title,type); 
} 
} 
} 
); 
//退出 

JMenuItem exit = new JMenuItem("退出"); 
exit.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
System.exit(0); 
} 
}); 
exit.setMnemonic('Q'); 
exit.setAccelerator(KeyStroke.getKeyStroke('Q',java.awt.Event.CTRL_MASK,true)); 
//查找 
JMenuItem find = new JMenuItem("查找"); 
find.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
} 
}); 
find.setMnemonic('F'); 
find.setAccelerator(KeyStroke.getKeyStroke('F',java.awt.Event.CTRL_MASK,true)); 
//剪切 
JMenuItem cut = new JMenuItem("剪切"); 
cut.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
text.cut(); 
} 
}); 
cut.setMnemonic('C'); 
cut.setAccelerator(KeyStroke.getKeyStroke('C',java.awt.Event.CTRL_MASK,true)); 
//复制 
JMenuItem copy = new JMenuItem("复制"); 
copy.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
text.copy(); 
} 
}); 
copy.setMnemonic('o'); 
copy.setAccelerator(KeyStroke.getKeyStroke('O',java.awt.Event.CTRL_MASK,true)); 
//粘贴 
JMenuItem paste = new JMenuItem("粘贴"); 
paste.addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e){ 
text.paste(); 
}}); 
paste.setMnemonic('P'); 
paste.setAccelerator(KeyStroke.getKeyStroke('P',java.awt.Event.CTRL_MASK,true)); 

JMenuItem about = new JMenuItem("关于"); 
about.addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e){ 
int type=JOptionPane.INFORMATION_MESSAGE; 
String title="关于"; 
String message="Designed by wenyouliang"; 
JOptionPane.showMessageDialog(panel,message,title,type); 
}}); 

JMenuItem color = new JMenuItem("颜色"); 
color.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e){
String title = "选取颜色";
Color co = JColorChooser.showDialog(panel,title, Color.black 
 ); 
text.setForeground(co);
}});
file.add(newFile); 
file.add(open); 
file.add(save); 
file.addSeparator(); 
file.add(exit); 
edit.add(cut); 
edit.add(copy); 
edit.add(paste); 
edit.add(find); 
edit.add(color);
help.add(about); 

} 
public static void main(String[] args) { 
Notepad notepad = new Notepad(); 
notepad.setSize(640, 480); 
notepad.setVisible(true); 
notepad.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
} 

}