这段代码为什么无法实现写入和读取，求解答，谢谢！

import java.awt.*;

import javax.swing.*;

import java.awt.event.*;
import java.io.*;
public class Filetest4 extends JFrame{
public static JTextArea getjt(){
JTextArea jt=new JTextArea();
return jt;
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame jf=new JFrame();
Container c=jf.getContentPane();

    JScrollPane js=new JScrollPane();
    js.setViewportView(getjt());
    JButton open=new JButton("写入文件");
    open.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            File file=new File("word.txt");
            try{
                FileWriter out=new FileWriter(file);
                String s=getjt().getText();
                out.write(s);
                out.close();
            }catch(Exception o){
                o.printStackTrace();
            }
        }
    });
    JButton close=new JButton("读取文件");
    close.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent e){
            File file=new File("word.txt");
            try{
                FileReader in=new FileReader(file);
                char[] ch=new char[1024];
                int len=in.read(ch);
                getjt().setText(new String(ch,0,len));
                in.close();
            }catch(Exception o){
                o.printStackTrace();
            }
        }
    });
    JPanel jp=new JPanel(new FlowLayout());
    jp.add(open);
    jp.add(close);
    c.setLayout(new BorderLayout());
    c.add(js,BorderLayout.CENTER);
    c.add(jp,BorderLayout.SOUTH);
    jf.setSize(200,200);
    jf.setVisible(true);
    jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


}

}

因为你每次getjt()的时候都是new一个JTextArea，新new的JTextArea里面没有输入，所以取出来的字符串是空，所以无法写入文件。