How to write to a file using Applet in Java

Problem Description

How to write to a file using Applet?

Solution

Following example demonstrates how to write to a file by making textarea for writing in a browser using TextArea() making Labels & then creating file using File() constructor.

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.applet.Applet;
import java.net.*;

public class WriteFile extends Applet {
   Button write = new Button("WriteToFile");
   Label label1 = new Label("Enter the file name:");
   TextField text = new TextField(20);
   Label label2 = new Label("Write your text:");
   TextArea area = new TextArea(10,20);
   
   public void init() {
      add(label1);
      label1.setBackground(Color.lightGray);
      add(text);
      add(label2);
      
      label2.setBackground(Color.lightGray);
      add(area);
      add(write,BorderLayout.CENTER);
      
      write.addActionListener(new ActionListener () {
         public void actionPerformed(ActionEvent e) { 
            new WriteText();
         }
      });
   } 
   public class WriteText {
      WriteText() { 
         try {
            String str = text.getText();
            
            if(str.equals("")) { 
               JOptionPane.showMessageDialog(null, "Please enter the file name!");
               text.requestFocus();
            } else { 
               File f = new File(str);
               if(f.exists()) {
                  BufferedWriter out = new BufferedWriter(new FileWriter(f,true));
                  if(area.getText().equals("")) {
                     JOptionPane.showMessageDialog (null,"Please enter your text!");
                     area.requestFocus();
                  } else {
                     out.write(area.getText());
                     if(f.canWrite()) {
                        JOptionPane.showMessageDialog(null, "Text is written in "+str);
                        text.setText("");
                        area.setText("");
                        text.requestFocus();
                     } else {
                        JOptionPane.showMessageDialog(null, "Text isn't written in "+str);
                     }
                     out.close();
                  }
               } else {
                  JOptionPane.showMessageDialog (null,"File not found!");
                  text.setText("");
                  text.requestFocus();
               }
            }
         } catch(Exception x) {
            x.printStackTrace();
         }
      }
   }
}

Result

The above code sample will produce the following result in a java enabled web browser.

View in Browser.