struts2 jcaptcha

servlet 代码：

package com.radicasys.signup.jcaptcha;



import java.awt.image.BufferedImage;

import java.io.ByteArrayOutputStream;

import java.io.IOException;



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 org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.springframework.context.ApplicationContext;

import org.springframework.web.context.support.WebApplicationContextUtils;



import com.octo.captcha.service.CaptchaServiceException;

import com.octo.captcha.service.image.ImageCaptchaService;

import com.sun.image.codec.jpeg.JPEGCodec;

import com.sun.image.codec.jpeg.JPEGImageEncoder;



public class ImageCaptchaServlet extends HttpServlet {

	private static final long serialVersionUID = 3258417209566116145L;



	private Log logger = LogFactory.getLog(this.getClass());



	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 image captcha service defined via the 

			//SpringFramework 

			ApplicationContext ctx = WebApplicationContextUtils

					.getRequiredWebApplicationContext(getServletContext());

			Object bean = ctx.getBean("jcaptchaService");

			ImageCaptchaService imageCaptchaService = (ImageCaptchaService) bean;



			// get the id that will identify the generated captcha. 

			// the same id must be used to validate the response 

			String captchaId = httpServletRequest.getParameter("captchaId");

			logger.debug("captchaIdParameter: "

					+ httpServletRequest.getParameter("captchaId"));

			if (captchaId == null) {

				// If a captcha id is not passed in, use the session id 

				captchaId = httpServletRequest.getSession().getId();

				logger.debug("httpServletRequest.session.id: "

						+ httpServletRequest.getSession().getId());

			}



			logger.debug("captchaId: " + captchaId);

			// call the ImageCaptchaService getChallenge method 

			BufferedImage challenge = imageCaptchaService

					.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();

	}

}

 web.xml加入：

<servlet>
		<servlet-name>jcaptcha</servlet-name>
		<servlet-class>
			com.radicasys.signup.jcaptcha.ImageCaptchaServlet
		</servlet-class>
		<load-on-startup>3</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>jcaptcha</servlet-name>
		<url-pattern>/user/jcaptcha</url-pattern>
	</servlet-mapping>

 

jsp页面代码如下：

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">

<meta http-equiv="expires" content="0">

 

<script language="javascript" type="text/javascript">
			function changeImage() {	
				document.getElementById('kaptchaImage').src = 'jcaptcha?captchaId=' + Math.random();
			}
		</script>

 

<tr>
			<th nowrap="nowrap"><fmt:message key="rememberPassword.code"/></th>
			<td>
			<s:url value="./jcaptcha" id="jcaptcha">
				<s:param name="captchaId" value="captchaId"/>
			</s:url>
			<img src="<s:property value="#jcaptcha"/>" width="130" id="kaptchaImage"
				name="photo" onclick="changeImage();"></td>
		</tr>
		<tr>
			<th></th>
			<td><a href="javascript:changeImage();" title="<fmt:message key="user.jcaptcha.see"/>"
				tabindex="-2" style="color: gray; width: 130px"><fmt:message key="user.jcaptcha.see"></fmt:message></a></td>


		</tr>
		<tr>
			<th></th>
			<td valign="top"><fmt:message key="user.validateCode"></fmt:message> <input type="text"
				name="jcaptchaResponse



" value=''></td>
		</tr>
		<tr>
			<td colspan="2"><s:submit value="%{getText('button.next')}" /></td>
		</tr>

 struts2 action中的代码：

private String jcaptchaResponse;
//set get method......
public boolean checkJcaptcha() {
		boolean flag = false;
		String id = getRequest().getSession().getId();
		if (StringUtils.isNotBlank(jcaptchaResponse)) {
			flag = imageCaptchaService.validateResponseForID(id,
					jcaptchaResponse);
		}
		return flag;
	}