带滚动条的文本文件

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


public class Ftest extends JFrame {
    private static final long serialVersionUID = 1L;
    private JPanel jContentPane = null;
    private JTextArea jTextArea = null;
    private JPanel controlPanel = null;
    private JButton openButton = null;
    private JButton closeButton = null;
    
 private JTextArea getJTextArea() {
        if (jTextArea == null) {
            jTextArea = new JTextArea();
        }
        return jTextArea;
    }

private JPanel getControlPanel() {
        if (controlPanel == null) {
            FlowLayout flowLayout = new FlowLayout();
            flowLayout.setVgap(1);
            controlPanel = new JPanel();
            controlPanel.setLayout(flowLayout);
            controlPanel.add(getOpenButton(), null);
            controlPanel.add(getCloseButton(), null);
        }
        return controlPanel;
    }


    private JButton getOpenButton() {
        if(openButton == null) {
            openButton = new JButton();
            openButton.setText("写入文件");
            openButton.addActionListener(new ActionListener() {
                public void actionPerformed(ActionEvent e) {
                    File file = new File("word.txt");
                    try    {
                        FileWriter out = new FileWriter(file);
                        String s = jTextArea.getText();
                        out.write(s);
                        out.close();                        
                    }catch (Exception e1) {
                        e1.printStackTrace();
                    }
                }
            });
    }
    return openButton;
}
private JButton getCloseButton() {
    if(closeButton == null) {
        closeButton = new JButton();
        closeButton.setText("读取文件");
        closeButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                File file = new File("word.txt");
                try    {
                    FileReader in = new FileReader(file);
                    char byt[] = new char[1024];
                    int len = in.read(byt);
                    jTextArea.setText(new String(byt, 0, len));
                    in.close();
                }
                catch (Exception e1) {
                    e1.printStackTrace();
                }    
            }
        });
    }
    return closeButton;
}

public Ftest() {
    super();
    initialize();
}
public void initialize() {
    this.setSize(300, 200);
    this.setContentPane(getJContentPane());
    this.setTitle("JFrame");
}
private JPanel getJContentPane() {
    if(jContentPane == null) {
        jContentPane = new JPanel();
        jContentPane.setLayout(new BorderLayout());
        jContentPane.add(getJTextArea(), BorderLayout.CENTER);
        jContentPane.add(getControlPanel(), BorderLayout.SOUTH);
    }
    return jContentPane;
}
    public static void main(String[] args) {
        Ftest thisClass = new Ftest();
        thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        thisClass.setVisible(true);
    }
}