Add jcaptcha-all.jar (provided in
bin-distribution
實(shí)例一個(gè)jcaptcha服務(wù),注意,必須是單例模式的
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:以上是默認(rèn)的一個(gè)實(shí)現(xiàn),下面是其他更多的實(shí)現(xiàn)
編寫一個(gè)產(chǎn)生圖片的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(); } } 為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 > 編寫你的客戶端的展示
<
img
src
="jcaptcha"
>
< input type ='text' name ='j_captcha_response' value ='' > 上面的src="jcaptcha" 就是調(diào)用了上面的servlet,text里是用戶填寫的確認(rèn)驗(yàn)證碼 后臺(tái)邏輯驗(yàn)證
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 } |
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