CAPTCHA IMAGE GENERATION IN OAF PAGE

THE DOCUMENT DESCRIBES HOW TO CREATE CAPTCHA IMAGE IN OAF PAGE:

Step 1: get captcha:

// to get the captchaImage Field in OAF page(code to be written in controller)=>

    OAImageBean captchaImage = (OAImageBean)webBean.findIndexedChildRecursive("CaptchaImageField");
    captchaImage.setSource("captchaservlet");

Step 2: Creation of captcha servlet:

Step 3: captchaservlet code to generate captcha image:

import com.sun.java.util.collections.Random;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.GradientPaint;
import java.awt.RenderingHints;

 

public class CaptchaServlet extends HttpServlet
{
  protected void processRequest(HttpServletRequest request,
                                  HttpServletResponse response)
                   throws ServletException, IOException {

      int width = 150;
      int height = 50;

      int PASSWORD_LENGTH = 5;
      Random rr= new Random();

          StringBuffer sb = new StringBuffer();  

          for (int x = 0; x < PASSWORD_LENGTH; x++)
          {
          int ran=rr.nextInt(3)+1;
          switch(ran)
            {
            case 1: sb.append((char)((int)(Math.random()*9)+48));
                   break;
            case 2: sb.append((char)((int)(Math.random()*26)+65));
                   break;
            case 3: sb.append((char)((int)(Math.random()*26)+97));
                   break;
          }
          }
  char newchar[] = sb.toString().toCharArray();

  //      char data[][] = {
  //          { 'z', 'e', 't', 'c', 'o', 'd', 'e' },
  //          { 'l', 'i', 'n', 'u', 'x' },
  //          { 'f', 'r', 'e', 'e', 'b', 's', 'd' },
  //          { 'u', 'b', 'u', 'n', 't', 'u' },
  //          { 'u', 'b', 'u', 'n', 't', 'u' },
  //          { 'r', 't', '3', 'j', 'n', 'z' },
  //          { 'f', 'g', 'e', '1', 't', 'l' },
  //          { 'a', 'x', 'k', 'y', '8', 'k' },
  //          { 'f', 'h', 't', 'q', 'a', 'z' },
  //          { 'r', 'q', 's', 'f', '8', '1' },
  //          { 'e', 'h', '5', 's', 'y', 'm' },
  //          { 'q', 't', 'r', 'i', 'w', 'r' },
  //          { 'j', 'e', 'e' }
  //      };

      BufferedImage bufferedImage = new BufferedImage(width, height,
                    BufferedImage.TYPE_INT_RGB);

      Graphics2D g2d = bufferedImage.createGraphics();

      Font font = new Font("Georgia", Font.BOLD, 18);
      g2d.setFont(font);

      RenderingHints rh = new RenderingHints(
             RenderingHints.KEY_ANTIALIASING,
             RenderingHints.VALUE_ANTIALIAS_ON);

      rh.put(RenderingHints.KEY_RENDERING,
             RenderingHints.VALUE_RENDER_QUALITY);

      g2d.setRenderingHints(rh);

      GradientPaint gp = new GradientPaint(0, 0,
      Color.red, 0, height/2, Color.black, true);

      g2d.setPaint(gp);
      g2d.fillRect(0, 0, width, height);

      g2d.setColor(new Color(220, 218, 222));

      Random r = new Random();
      int index = Math.abs(r.nextInt()) % 5;
  
  //      String captcha = String.copyValueOf(data[index]);
      String captcha = String.copyValueOf(newchar);
      Object captcha123 = (Object)captcha;
     //    request.getSession(true).setAttribute("captcha",captcha123);
      request.getSession(true).putValue("captcha",captcha123);
     //HttpSession session = request.getSession();

      int x = 0;
      int y = 0;

      for (int i=0; i<newchar.length; i++) {
          x += 10 + (Math.abs(r.nextInt()) % 15);
          y = 20 + Math.abs(r.nextInt()) % 20;
          g2d.drawChars(newchar, i, 1, x, y);
      }

      g2d.dispose();

      response.setContentType("image/png");
      OutputStream os = response.getOutputStream();
      ImageIO.write(bufferedImage, "png", os);
      os.close();
    }

    protected void doGet(HttpServletRequest request,
                         HttpServletResponse response)
                             throws ServletException, IOException {
        processRequest(request, response);
    }

    protected void doPost(HttpServletRequest request,
                          HttpServletResponse response)
                              throws ServletException, IOException {
        processRequest(request, response);
}

}

Step 4: Validation for Captcha on submit:

String captcha = pageContext.getSessionValueDirect("captcha") + "";

String code = pageContext.getParameter("CaptchaTextField");

if ((captcha != null) && (code != null))
            {
              if (captcha.equals(code))
              {
                pageContext.writeDiagnostics(this, " Correct Captcha Code----", 1);
           
              }