验证码

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Add jcaptcha-all.jar (provided in bin-distribution) and ehcache.jar (not provided see ehcache site) to your application class path, ie in you WEB-INF/lib folder. 实例一个jcaptcha服务，注意，必须是单例模式的 import com.octo.captcha.service.image.ImageCaptchaService; import com.octo.captcha.service.image.DefaultManageableImageCaptchaService; public class CaptchaServiceSingleton { private static ImageCaptchaService instance = new DefaultManageableImageCaptchaService(); public static ImageCaptchaService getInstance(){ return instance; } } 注:以上是默认的一个实现，下面是其他更多的实现 SimpleListSoundCaptchaEngine //还可以用声音，真爽哦 SpellerSoundCaptchaEngine SpellerSoundCaptchaEngine DefaultGimpyEngineCaptcha BaffleListGimpyEngineCaptcha BasicListGimpyEngineCaptcha DeformedBaffleListGimpyEngineCaptcha DoubleRandomListGimpyEngineCaptcha SimpleListImageCaptchaEngineCaptcha SimpleFishEyeEngineCaptcha 具体请参考 官方说明 编写一个产生图片的servlet 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(); } } 为servlet修改web.xml配置文件 < servlet > < servlet-name > jcaptcha </ servlet-name > < servlet-class > ImageCaptchaServlet </ servlet-class > < load-on-startup > 0 </ load-on-startup > </ servlet > < servlet-mapping > < servlet-name > jcaptcha </ servlet-name > < url-pattern > /jcaptcha </ url-pattern > </ servlet-mapping > 编写你的客户端的展示 < img src ="jcaptcha" > < input type ='text' name ='j_captcha_response' value ='' > 上面的src="jcaptcha" 就是调用了上面的servlet,text里是用户填写的确认验证码 后台逻辑验证 Boolean isResponseCorrect = Boolean.FALSE; // remenber that we need an id to validate! String captchaId = httpServletRequest.getSession().getId(); // retrieve the response String response = httpServletRequest.getParameter( " j_captcha_response " ); // Call the Service method try { isResponseCorrect = CaptchaServiceSingleton.getInstance().validateResponseForID(captchaId, response); } catch (CaptchaServiceException e) { // should not happen, may be thrown if the id is not valid }