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          安裝

          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.

          實例一個jcaptcha服務,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:以上是默認的一個實現,下面是其他更多的實現

          SimpleListSoundCaptchaEngine?? //還可以用聲音,真爽哦
          SpellerSoundCaptchaEngine
          SpellerSoundCaptchaEngine
          DefaultGimpyEngineCaptcha???????????
          BaffleListGimpyEngineCaptcha???????????
          BasicListGimpyEngineCaptcha???????????
          DeformedBaffleListGimpyEngineCaptcha???????????
          DoubleRandomListGimpyEngineCaptcha???????????
          SimpleListImageCaptchaEngineCaptcha???????????
          SimpleFishEyeEngineCaptcha
          具體請參考官方說明

          編寫一個產生圖片的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"? 就是調用了上面的servlet,text里是用戶填寫的確認驗證碼

          后臺邏輯驗證
          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
          ??????????? }

          posted on 2006-10-28 10:05 無聲 閱讀(642) 評論(0)  編輯  收藏 所屬分類: 職場生活
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