加速世界小说21卷翻译:主要想实现保存输入的文本 保存事件如何实现?

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

public class TextArea
{
public static void main(String args[])
{
TextAreaFrame frame= new TextAreaFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
class TextAreaFrame extends JFrame
{
public TextAreaFrame()
{
setTitle("文本文档");
setSize(DEFAULT_WIDHT,DEFAULT_HEIGHT);
buttonPanel=new JPanel();
JButton saveButton=new JButton("保存");
buttonPanel.add(saveButton);
saveButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
//?如何实现?
}
});

exitButton=new JButton("退出");
buttonPanel.add(exitButton);
exitButton.addActionListener(new
ActionListener()
{
public void actionPerformed(ActionEvent event)
{
System.exit(0);
}
});
getContentPane().add(buttonPanel,BorderLayout.SOUTH);
textArea=new JTextArea(20,10);
scrollPane=new JScrollPane(textArea);
getContentPane().add(scrollPane,BorderLayout.CENTER);
}

public static final int DEFAULT_WIDHT=400;
public static final int DEFAULT_HEIGHT=400;
private JTextArea textArea;
private JScrollPane scrollPane;
private JPanel buttonPanel;
private JButton exitButton;
}
import java.io.*;