问答题

阅读下列程序，请写出该程序的功能。
import java.util.*;import java.io.*;
import java.awt.*; import javax.swing.*;import java.awt.event.*;
class MyFrame extends JFrame implements ActionListener{
JTextArea text; JTextField tf; BufferedWriter out;
MyFrame(){
super("一个测试程序");
Container con=getContentPane();
text=new JTextArea(10,20);
text.setBackground (Color.cyan);
tf=new JTextField ();
tf.addActionListener(this);
con.setLayout(new BorderLayout());
con.add (text, "Center"); con.add(tf, "South");
setVisible(true); pack();
{
public void actionPerformed(ActionEvent e) {
if(e.getSource()==tf){
try{
out=new BufferedWriter(new FileWriter(tf. getText()));
StringTokenizer tokens=new StringTokenizer(text.getText());
int n=tokens.countTokens(),i;
out.write(tokens.nextToken ()+"\r\n");
}
out.flush (); text.setText (null); System.exit(0);
}catch(IOException exp) {
text.setText("文件写出错! \n");
}
}
}
}
public class Test36 {
public static void main(String args[ ]){
new MyFrame();
}
}