那位高手帮忙看看怎样将jtextField中的内容输出在jtextArea中显示！急急急

希望在jtextfield中按 回车 显示输出在jtextArea中，在这个代码基础上，谢谢啊！！

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

import javax.swing.*;
import javax.swing.text.JTextComponent;
public class Testtalk {
public static void main(String[] args) {
JFrame f=new JFrame("^聊天^");
f.setSize(400,250);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JTextField jtf=new JTextField(300);

f.add(jtf,"South");
JTextArea jta=new JTextArea();
JScrollPane jsp=new JScrollPane(jta);
f.add(jsp);
f.setVisible(true);
ActionListener l=new ActionListener(){
public void actionPerformed(ActionEvent arg0){
System.out.println("action!");
}
};
jtf.addActionListener(l);
}

}

//这样就行了

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

import javax.swing.*;
import javax.swing.text.JTextComponent;

public class Testtalk {
public static void main(String[] args) {
JFrame f = new JFrame("^聊天^");
f.setSize(400, 250);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

final JTextField jtf = new JTextField(300);

f.add(jtf, "South");
final JTextArea jta = new JTextArea();
final JScrollPane jsp = new JScrollPane(jta);
f.add(jsp);
f.setVisible(true);
ActionListener l = new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
jta.setText((jta.getText()+"\r\n"+jtf.getText()));
jtf.setText("");
}
};
jtf.addActionListener(l);
}

}

你说呢...