Java-GUI(练习-打开文件)-(练习-保存文件)

import java.awt.*;
import java.awt.event.*;
import java.io.*;
class MyMenuTest
{
private Frame f;
private MenuBar bar;
private TextArea ta;
private Menu fileMenu;
private MenuItem openItem,saveItem,closeItem;

private FileDialog openDia,saveDia;

private File file;
MyMenuTest()
{
init();
}

public void init()
{
f = new Frame("my window");
f.setBounds(300,100,650,600);
// f.setLayout(new FlowLayout());

bar = new MenuBar();

ta = new TextArea();

fileMenu = new Menu("文件");

openItem = new MenuItem("打开");
saveItem = new MenuItem("保存");
closeItem = new MenuItem("退出");

fileMenu.add(openItem);
fileMenu.add(saveItem);
fileMenu.add(closeItem);
bar.add(fileMenu);

f.setMenuBar(bar);

openDia = new FileDialog(f,"我要打开",FileDialog.LOAD);
saveDia = new FileDialog(f,"我要保存",FileDialog.SAVE);

f.add(ta);
myEvent();

f.setVisible(true);
}

private void myEvent()
{
saveItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
if(file==null)
{
saveDia.setVisible(true);
String dirPath = saveDia.getDirectory();
String fileName = saveDia.getFile();
if(dirPath==null || fileName==null)
return;
file = new File(dirPath,fileName);
}

try
{
BufferedWriter bufw = new BufferedWriter(new FileWriter(file));

String text = ta.getText();

bufw.write(text);
// bufw.flush();
bufw.close();
}
catch(IOException ex)
{
throw new RuntimeException("错误");
}
}
});
openItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
openDia.setVisible(true);
String dirPath = openDia.getDirectory();
String fileName = openDia.getFile();
// System.out.println(dirPath+"..."+fileName);
if(dirPath==null || fileName==null)
return;
ta.setText("");
file = new File(dirPath,fileName);

try
{
BufferedReader bufr = new BufferedReader(new FileReader(file));

String line = null;

while((line=bufr.readLine())!=null)
{
ta.append(line+"\r\n");
}
bufr.close();
}
catch(IOException ex)
{
throw new RuntimeException("读取失败");
}
}
});

closeItem.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
});
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
public static void main(String[] args)
{
new MyMenuTest();
}
}