Jcaptcha图片验证码

package com.nothing.gamesf.common.jcaptcha;

import java.awt.image.BufferedImage;
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.io.output.ByteArrayOutputStream;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.web.context.WebApplicationContext;
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;


/**
 * 提供验证码图片的Servlet
 *
 * @author wzw
 * @version $Id: JcaptchaServlet.java 2015年3月30日 上午9:48:17 $
 *
 */
@SuppressWarnings("serial")
public class JcaptchaServlet extends HttpServlet {
	public static final String CAPTCHA_IMAGE_FORMAT = "jpeg";

	private ImageCaptchaService captchaService;

	@Override
	public void init(ServletConfig servletConfig) throws ServletException {
		super.init(servletConfig);  
		WebApplicationContext appCtx = WebApplicationContextUtils
				.getWebApplicationContext(getServletContext());
		captchaService = (ImageCaptchaService) BeanFactoryUtils
				.beanOfTypeIncludingAncestors(appCtx, ImageCaptchaService.class);
	}

	@Override
	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) 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 = request.getSession().getId();  
			BufferedImage challenge = captchaService.getImageChallengeForID(
					captchaId, request.getLocale());
            // a jpeg encoder  
            JPEGImageEncoder jpegEncoder = JPEGCodec  
                    .createJPEGEncoder(jpegOutputStream);  
            jpegEncoder.encode(challenge); 
		} catch (IllegalArgumentException e) {
			response.sendError(HttpServletResponse.SC_NOT_FOUND);
			return;
		} catch (CaptchaServiceException e) {
			response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
			return;
		}
		// catch (JimiException e) {
		// response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
		// return;
		// }

		captchaChallengeAsJpeg = jpegOutputStream.toByteArray();

		// flush it in the response
		response.setHeader("Cache-Control", "no-store");
		response.setHeader("Pragma", "no-cache");
		response.setDateHeader("Expires", 0);
		response.setContentType("image/" + CAPTCHA_IMAGE_FORMAT);

		ServletOutputStream responseOutputStream = response.getOutputStream();
		responseOutputStream.write(captchaChallengeAsJpeg);
		responseOutputStream.flush();
		responseOutputStream.close();
	}
}

 web.xml添加上

<servlet>
		<servlet-name>Jcaptcha</servlet-name>
		<servlet-class>com.nothing.gamesf.common.jcaptcha.JcaptchaServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>Jcaptcha</servlet-name>
		<url-pattern>/captcha.svl</url-pattern>
	</servlet-mapping>

 在控制层注入使用

@Resource
    private ImageCaptchaService imageCaptchaService;

imageCaptchaService.validateResponseForID(request.getSession().getId(), captcha);

 根据返回值判断是否通过