JCaptcha with JSP Servlet

First need to download JAR file for JCaptcha from

http://sourceforge.net/project/downloading.php?groupname=jcaptcha&filename=jcaptcha-bin-1.0-RC6.zip&use_mirror=osdn

You also need common apache library.

Now create a Web Applications in NetBeans or Eclipse and add the jars to your application classpath.

Now need to create Other classes:

CaptchaServiceSingleton.java

package com.ss;

import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.ImageCaptchaService;
import com.octo.captcha.service.image.DefaultManageableImageCaptchaService;

public class CaptchaServiceSingleton {

 private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService(
   new FastHashMapCaptchaStore(),new MyCaptchaEngine(),180,100000,75000);

 public static ImageCaptchaService getInstance() {
  return instance;
 }

}

And MyCaptchaEngine.java

package com.ss;

import java.awt.Font;
import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.FunkyBackgroundGenerator;
import com.octo.captcha.component.image.color.RandomRangeColorGenerator;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.RandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;

public class MyCaptchaEngine extends ListImageCaptchaEngine {

 protected void buildInitialFactories() {

  WordGenerator wgen = new RandomWordGenerator(
    "ABCDEFGHIJKLMNPQRSTUVWXYZ123456789");
  RandomRangeColorGenerator cgen = new RandomRangeColorGenerator(
    new int[] { 0, 100 },new int[] { 0, 100 },new int[] { 0, 100 });

  TextPaster textPaster = new RandomTextPaster(new Integer(4),
    new Integer(6), cgen, true);

  BackgroundGenerator backgroundGenerator = new FunkyBackgroundGenerator(
    new Integer(200), new Integer(100));

  /**
   * BackgroundGenerator backgroundGenerator = new
   * GradientBackgroundGenerator(new Integer(200),new
   * Integer(100),Color.blue,Color.white);
   */

  Font[] fontsList = new Font[] {
    new Font("Arial", 1, 10),new Font("Tahoma", 10, 15),new Font("Verdana", 11, 12),
  };

  FontGenerator fontGenerator = new RandomFontGenerator(new Integer(20),
    new Integer(35), fontsList);

  WordToImage wordToImage = new ComposedWordToImage(fontGenerator,
    backgroundGenerator, textPaster);

  this.addFactory(new GimpyFactory(wgen, wordToImage));

 }
}

Now Create Servlet named ImageCaptchaServlet:

import com.octo.captcha.service.CaptchaServiceException;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;

public class ImageCaptchaServlet extends HttpServlet {

 public void init(ServletConfig servletConfig) throws ServletException {
  super.init(servletConfig);
 }

 protected void doGet(HttpServletRequest httpServletRequest,
   HttpServletResponse httpServletResponse) throws ServletException,
   IOException {

  byte[] captchaChallengeAsJpeg = null;
  // the output stream to render the captcha image as jpeg into
  ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
  try {
   // get the session id that will identify the generated captcha.
   // the same id must be used to validate the response, the session id
   // is a good candidate!
   String captchaId = httpServletRequest.getSession().getId();

   // call the ImageCaptchaService getChallenge method
   BufferedImage challenge = CaptchaServiceSingleton.getInstance().getImageChallengeForID(
     captchaId,httpServletRequest.getLocale());

   // a jpeg encoder
   JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);
   jpegEncoder.encode(challenge);

  } catch (IllegalArgumentException e) {
   httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
   return;
  } catch (CaptchaServiceException e) {
   httpServletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
   return;
  }

  captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
  // flush it in the response

  httpServletResponse.setHeader("Cache-Control", "no-store");
  httpServletResponse.setHeader("Pragma", "no-cache");
  httpServletResponse.setDateHeader("Expires", 0);
  httpServletResponse.setContentType("image/jpeg");

  ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream();

  responseOutputStream.write(captchaChallengeAsJpeg);
  responseOutputStream.flush();
  responseOutputStream.close();
 }
}

Create other Servlet named: Register.java

package com.ss;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.octo.captcha.service.CaptchaServiceException;

public class Register extends HttpServlet {

 public Register() {
  super();
 }

 public void destroy() {
  super.destroy(); // Just puts "destroy" string in log
  // Put your code here
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  response.setContentType("text/html");
  PrintWriter out = response.getWriter();

  out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
  out.println("<HTML>");
  out.println(" <HEAD><TITLE>A Servlet</TITLE></HEAD>");
  out.println(" <BODY>");
  out.print(" This is ");
  out.print(this.getClass());
  out.println(", using the POST method");
  out.println("<br />");

  Boolean isResponseCorrect = Boolean.FALSE;
  // remenber that we need an id to validate!
  String captchaId = request.getSession().getId();
  // retrieve the response
  String response2 = request.getParameter("j_captcha_response");
  // Call the Service method
  try {
   isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId,response2);
   if (isResponseCorrect)
    out.println(" Your Code is matched with captcha..." + captchaId);
   else
    out.println(" Your Code is not matched with captcha..." + captchaId);
  } catch (CaptchaServiceException e) {
   // should not happen, may be thrown if the id is not valid
   out.println(" Erro on Captcha..." + e);
  }

  out.println("<br />");
  out.println(" </BODY>");
  out.println("</HTML>");
  out.flush();
  out.close();
 }

 public void init() throws ServletException {
 }
}

Create JSP page for captcha:

index.jsp

<html>
 <body>
  <form action="./register" method="post">&nbsp; 
   <input type='text' name='j_captcha_response' value=''>
   <br />
   <input type="submit" value="Submit" />
  </form>
  <br />
 </body>
</html>

So, now at end your WEB.xml will have entry like with two servlet:

<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

 <servlet>
  <description>Captcha Servlet</description>
  <display-name>
   This is the display name of my J2EE component
  </display-name>
  <servlet-name>jcaptcha</servlet-name>
  <servlet-class>com.ss.ImageCaptchaServlet</servlet-class>
  <load-on-startup>0</load-on-startup>
 </servlet>


 <servlet>
  <description>Captcha Servlet</description>
  <display-name>
   This is the display name of my J2EE component
  </display-name>
  <servlet-name>Register</servlet-name>
  <servlet-class>com.ss.Register</servlet-class>
 </servlet>

 <servlet-mapping>
  <servlet-name>jcaptcha</servlet-name>
  <url-pattern>/jcaptcha</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
  <servlet-name>Register</servlet-name>
  <url-pattern>/register</url-pattern>
 </servlet-mapping>

 <welcome-file-list>
  <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>

</web-app>

And run the application.