<pre class="brush: java">

 @Override 
 protected void buildInitialFactories() {

 // Range of characters to generate
 // 
 WordGenerator wgen =
 new RandomWordGenerator
 ("abcdefghijklmsonqrstuvwxyz123456789");
 
 // Range of text colors
 RandomRangeColorGenerator cgen = 
 new RandomRangeColorGenerator(new int[]{20, 25}, 
 new int[]{50, 120}, new int[]{50, 255});
 
 // Number of challenge characters 
 TextPaster textPaster =
 new RandomTextPaster(new Integer(7), 
 new Integer(7),
 cgen, Boolean.valueOf(true));

 // Background and size of the image.
 
 GradientBackgroundGenerator 
 background = new GradientBackgroundGenerator(250,
 50,
 Color.white,
 Color.RED);


 // Alternate background options.

 
 // FunkyBackgroundGenerator background = 
 // new FunkyBackgroundGenerator (new Integer(250), new Integer(50));
 
 
 // UniColorBackgroundGenerator 
 // background = 
 // new UniColorBackgroundGenerator (250,50);
 //
 
 // Text fonts 
 Font fontsList[] = {
 new Font("Arial", 0, 10), 
 new Font("Tahoma", 0, 10), 
 new Font("Verdana", 0, 10)
 };

 FontGenerator fontGenerator =
 new RandomFontGenerator(
 new Integer(20), new Integer(35), fontsList);

 WordToImage wordToImage =
 new ComposedWordToImage
 (fontGenerator, background, textPaster);

 addFactory(new GimpyFactory(wgen, wordToImage));
 
 
 }
 
</pre>



Our image engine is an implementation of com.octo.captcha.engine.image.ListImageCaptchaEngine. We are only required to 

implement the above method which is buildInitialFactories (). We name this class CustomImageEngine. Please 

see the embedded comments for explaination of each line. Below is the class that contain our buildInitialFactories() method 

 above.



<pre class="brush: java">

 class CustomImageEngine implements ListImageCaptchaEngine {
 CustomImageEngine () {
 }

 @Override 
 protected void buildInitialFactories() {
 // Above code
 } 
 }
 
</pre>





If you are using Netbeans press ctrl-alt-i to include the required imports. Below is our singleton service. Visit 

the JCaptcha website for more details of the classes used in our service.



<pre class="brush: java">

public class CatchaService {

 private static ImageCaptchaService instance = null; 

 public static ImageCaptchaService getInstance() {

 if (instance == null) {
 CustomImageEngine engine = new CustomImageEngine();
 instance = new DefaultManageableImageCaptchaService 
 (new FastHashMapCaptchaStore(), 
 engine, 180, 0x186a0, 0x124f8);
 } 
 return instance;
 }
}
 
</pre>




And our servlet doGet method. Please note that this is a direct copy from JCaptcha with very slight modification.



<pre class="brush: java">
 
 @Override
 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 =
 CaptchaService.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();
 }

 
 
</pre>



I would like to emphasize the call to CaptchaService above. That is where image creation occurs. 


We create/save our servlet as CatchaServlet. If you are using Netbeans, creating the servlet would also update your 

web.xml. Below is the servlet entry into your web.xml.




<pre class="brush: xml">

 &lt;servlet>
 &lt;servlet-name>CaptchaServlet&lt;/servlet-name>
 &lt;servlet-class>demo.CaptchaServlet&lt;/servlet-class>
 &lt;load-on-startup>0&lt;/load-on-startup>
 &lt;/servlet>

 &lt;servlet-mapping>
 &lt;servlet-name>CaptchaServlet&lt;/servlet-name>
 &lt;url-pattern>/CaptchaServlet&lt;/url-pattern> 
 &lt;/servlet-mapping>
 
</pre>




The JSF page. We used PrimeFaces in this demonstration.




<pre class="brush: xml">

&lt;h:panelGrid style="border: 1px dotted lightgray;
 font-size:11px;" > 

 &lt;br/>
 &lt;p:graphicImage cache="false" id="image" value="/CaptchaServlet"/> 

 &lt;h:panelGrid style="font-size:10px;" columns="3"
 cellpadding="10"> 
 &lt;p:inputText style="font-size:11px;" 
 value="#{indexBean.challenge}"/>
 &lt;p:commandButton style="font-size:10px;" 
 value="submit" 
 actionListener="#{indexBean.submit}" />
 &lt;p:commandButton value="Refresh"
 update="image" style="font-size: 10px;"
 actionListener="#{indexBean.update}" /> 

 &lt;/h:panelGrid> 
&lt;/h:panelGrid>

 
</pre>




The backing bean of the snippet above.



<pre class="brush: java">

 public void update (ActionEvent e) {
 FacesContext context = FacesContext.getCurrentInstance(); 
 HttpServletRequest request = 
 (HttpServletRequest) 
 context.getExternalContext().getRequest();

 // Create new session
 request.getSession(true); 
 
 }
 
 public void submit (ActionEvent e) {
 FacesContext context = FacesContext.getCurrentInstance();
 HttpServletResponse response = 
 (HttpServletResponse) 
 context.getExternalContext().getResponse();
 HttpServletRequest request = (HttpServletRequest) 
 context.getExternalContext().getRequest();
 String id = request.getSession().getId();
 
 String entry = getChallenge();
 boolean valid;
 try {
 
 valid = CaptchaService.getInstance().
 validateResponseForID(id, entry);
 }
 catch(CaptchaServiceException ex) {
 
 }
 
 //
 // The main body of your code 
 //
 }
 
 // Input textfield
 private String challenge; 
 public String getChallenge () {
 return challenge;
 }

 public void setChallenge (String s) {
 challenge = s;
 }

 
</pre>



The sample outputs we promised you. Organize your page depending on your needs.



<table>
<tr>
<td>
<img loading="lazy" src="https://cdn.kahimyang.com/resources/cap1.png" />
</td>
<td>
Gradient background
</td>
</tr>
<tr>
<td>
<img loading="lazy" src="https://cdn.kahimyang.com/resources/cap2.png" />
</td>
<td>
Funky background
</td>
</tr>
</table>


 


That's it. Good luck.

Using JCaptcha as an alternate to Recaptcha for your JSF project