验证码 验证码例子 jcaptcha jcaptcha例子

package org.txl.yzm.app; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.octo.captcha.service.CaptchaServiceException; import com.octo.captcha.service.image.DefaultManageableImageCaptchaService; import com.octo.captcha.service.image.ImageCaptchaService; import com.octo.captcha.service.multitype.GenericManageableCaptchaService; import com.octo.captcha.service.multitype.MultiTypeCaptchaService; import com.sun.image.codec.jpeg.JPEGCodec; import com.sun.image.codec.jpeg.JPEGImageEncoder; public class YanZheMServlet extends HttpServlet { private static final String CAPTCHA_IMAGE_FORMAT="jpeg"; // private MultiTypeCaptchaService captchaService = new GenericManageableCaptchaService(); protected void doGet(final HttpServletRequest req, final HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub this.doPost(req, resp); } protected void doPost(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub String p = request.getParameter("M"); System.out.println("==========================="+p); } public void showPicture(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception { byte[] captchaChallengeAsJpeg = null; //存储Captcha Test使用的图片 ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream(); try { //借助于HttpSession ID存储Captcha ID，开发者也可以借助于其他惟一值 String captchaId = httpServletRequest.getSession().getId(); //获得Captcha Test使用的图片内容 BufferedImage challenge = JCaptchaServiceSingleton.getInstance() .getImageChallengeForID(captchaId, httpServletRequest.getLocale()); //输出JPEG格式 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(); //确保Captcha Test的安全性、可靠性 httpServletResponse.setHeader("Cache-Control", "no-store"); httpServletResponse.setHeader("Pragma", "no-cache"); httpServletResponse.setDateHeader("Expires", 0); //输出JPEG图片 httpServletResponse.setContentType("image/jpeg"); ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream(); responseOutputStream.write(captchaChallengeAsJpeg); responseOutputStream.flush(); responseOutputStream.close(); } }