JCaptchaFilter.java

/**
 * JCaptchaFilter.java
 * 2014-4-22
 */
package com.mtools.core.plugin.web.jcaptcha;
 
import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.filter.OncePerRequestFilter;

/**
 * 生成验证码
 * <p>User: zhang
 *  
 */
public class JCaptchaFilter extends OncePerRequestFilter {

    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {

        response.setDateHeader("Expires", 0L);
        response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");
        response.addHeader("Cache-Control", "post-check=0, pre-check=0");
        response.setHeader("Pragma", "no-cache");
        response.setContentType("image/jpeg");

        String id = request.getRequestedSessionId();
        BufferedImage bi = JCaptcha.captchaService.getImageChallengeForID(id);

        ServletOutputStream out = response.getOutputStream();

        ImageIO.write(bi, "jpg", out);
        try {
            out.flush();
        } finally {
            out.close();
        }
    }


}