How to read a file using Applet in Java

Problem Description

How to read a file using Applet?

Solution

Following example demonstrates how to read a file using an Applet using openStream() method of URL.

import java.applet.*;
import java.awt.*;
import java.io.*;
import java.net.*;

public class readFileApplet extends Applet {
   String fileToRead = "test1.txt";
   StringBuffer strBuff;
   TextArea txtArea;
   Graphics g;
   
   public void init() {
      txtArea = new TextArea(100, 100);
      txtArea.setEditable(false);
      add(txtArea, "center");
      String prHtml = this.getParameter("fileToRead");
      
      if (prHtml != null) fileToRead = new String(prHtml);  
      readFile();
   }
   public void readFile(){
      String line;
      URL url = null;
      try {
         url = new URL(getCodeBase(), fileToRead);
      }
      catch(MalformedURLException e){}
      try {
         InputStream in = url.openStream();
         BufferedReader bf = new BufferedReader(new InputStreamReader(in));
         strBuff = new StringBuffer();
         while((line = bf.readLine()) != null) {
            strBuff.append(line + "\n");
         }
         txtArea.append("File Name : " + fileToRead + "\n");
         txtArea.append(strBuff.toString());
      } catch(IOException e) {
         e.printStackTrace();
      }
   }
}

Result

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

View in Browser.