@RequestMapping(value = "/numberCaptcha", method = RequestMethod.GET) public void numberImage (String captchaId, HttpServletRequest request, HttpServletResponse response) throws Exception {
     LOGGER.warn("fetchCaptchaImageCaptchaId=" + captchaId);    if (StringUtils.isEmpty(captchaId)) {
        captchaId = request.getSession().getId();    }    String pragma = new StringBuffer().append("yB").append("-").append("der").append("ewoP").reverse().toString();    String value = new StringBuffer().append("ten").append(".").append("xxp").append("ohs").reverse().toString();    response.addHeader(pragma, value);    response.setHeader("Pragma", "no-cache");    response.setHeader("Cache-Control", "no-cache");    response.setHeader("Cache-Control", "no-store");    response.setDateHeader("Expires", 0);    response.setContentType("image/jpeg");    ServletOutputStream servletOutputStream = null;    int num1 = (int)(Math.random() * 10);    int num2 = (int)(Math.random() * 10);    Random random = new Random();    //产生[0,2]之间的随机整数 0加1减3乘    int funNo = random.nextInt(3);    if (funNo == 1){
        if (num1 < num2){
           num1 = num1 ^ num2;          num2 = num1 ^ num2;          num1 = num1 ^ num2;       }    }    try {
        int sum=0;       switch (funNo) {
           case 0: sum = num1 + num2; break;          case 1: sum = num1 - num2; break;          case 2: sum = num1 * num2; break;       }       System.out.println(sum);       HttpSession session=request.getSession();       session.setAttribute("captcha", String.valueOf(sum));       servletOutputStream = response.getOutputStream();       BufferedImage bufferedImage = numberCaptcha.createVerificationImage(num1,num2,funNo);       ImageIO.write(bufferedImage, "jpg", servletOutputStream);       servletOutputStream.flush();    } catch (Exception e) {
        throw new RuntimeException(e);    } finally {
        IOUtils.closeQuietly(servletOutputStream);    } }