import java.io.*;
import javax.swing.*;
import java.awt.FlowLayout;
import java.awt.event.*;
public class WriterTo extends JFrame implements ActionListener{
 JButton b;JTextField t;
 public WriterTo(){
  super("文本框内容写入文件");
  JLabel l=new JLabel("请输入内容：");
  t=new JTextField(20);
  b=new JButton("写入");
  b.addActionListener(this);
  this.add(l);
  this.add(t);
  this.add(b);
  this.setLayout(new FlowLayout());
  this.pack();
  this.setVisible(true);
 }
 public void actionPerformed(ActionEvent e) {
  if(e.getSource()==b){
   if(t.getText().equals("")){
    JOptionPane.showMessageDialog(null,"请输入内容~","错误",JOptionPane.ERROR_MESSAGE);
    t.grabFocus();
   }else{
    write(t.getText());
    JOptionPane.showMessageDialog(null,"写入成功","提示",JOptionPane.INFORMATION_MESSAGE);
   }
  }
 }
  public void write(String line){
   try{
    File f=new File("C:\\Users\\Administrator\\Desktop\\java\\就是这里.txt");//向指定文本框内写入
    FileWriter fw=new FileWriter(f);
    fw.write(line);
    fw.close();
   }catch(Exception e){
   }
  }
  public static void main(String[] args) {
   new WriterTo();
  }
}