jcaptcha sample 制作验证码详解编程语言

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    Created by marc antoine garrigue, last modified by Jeremy Waters on Feb 23, 2012 
 
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Description 
 
This integration module provides the shortest way to integrate JCaptcha to your web application. 
This module is available since jcaptcha 2.0 
 
This integration module provides the new default captcha configuration : 
 
All you need to do is add the jcaptcha jar to your project, make a reference to the SimpleImageCaptchaServlet in your web.xml and then use the servlet session id to validate what the user submits on your form against the captcha service. 
Set up 
 
    Add the jcaptcha jar file into the WEB-INF/lib directory of your .war file 
    If your app or server do not already have commons-logging and commons-collection into the WEB-INF/lib directory of your .war 
 
    Put the reference in your web.xml (checking that the url-pattern path matches up with what you put in your html fragment above): 
 
<servlet> 
        <servlet-name>jcaptcha</servlet-name> 
        <servlet-class>com.octo.captcha.module.servlet.image.SimpleImageCaptchaServlet</servlet-class> 
</servlet> 
<servlet-mapping> 
        <servlet-name>jcaptcha</servlet-name> 
        <url-pattern>/jcaptcha.jpg</url-pattern> 
</servlet-mapping> 
 
    Add the folowing image tag to the form you want to protect, this call will asks the SimpleImageCaptchaServlet to generate a fresh new captcha 
 
<form action="submit.action"> 
... 
    <img src="jcaptcha.jpg" /> <input type="text" name="jcaptcha" value="" /> 
... 
</form> 
 
    In your code that manages the submit action add the following code fragment to validate the user input 
 
String userCaptchaResponse = request.getParameter("jcaptcha"); 
boolean captchaPassed = SimpleImageCaptchaServlet.validateResponse(request, userCaptchaResponse); 
if(captchaPassed){ 
// proceed to submit action 
}else{ 
// return error to user 
} 
 
And that's it! 
Sample Web App 
 
    see the attached sample web app (warning, this war contains commons-logging and commons-collections) 
 
Jcaptcha 2.0 jars 
 
    jcaptcha-api-1.0.jar 
    jcaptcha-2.0-alpha-1-SNAPSHOT.jar 
    jcaptcha-integration-simple-servlet-2.0-alpha-1-SNAPSHOT.jar 
    filters-2.0.235.jar