/**
  * 获取验证码（Gif版本）
  * @param response
  */
 @RequestMapping(value="getGifCode",method=RequestMethod.GET)
 public void getGifCode(HttpServletResponse response,HttpServletRequest request){
  try {
  response.setHeader("Pragma", "No-cache"); 
   response.setHeader("Cache-Control", "no-cache"); 
   response.setDateHeader("Expires", 0); 
   response.setContentType("image/gif"); 
   /**
    * gif格式动画验证码
    * 宽，高，位数。
    */
   Captcha captcha = new GifCaptcha(146,33,4);
   //输出
   captcha.out(response.getOutputStream());
   HttpSession session = request.getSession(true); 
   //存入Session
   session.setAttribute("_code",captcha.text().toLowerCase()); 
  } catch (Exception e) {
  LoggerUtils.fmtError(getClass(),e, "获取验证码异常：%s",e.getMessage());
  }
 }

 /**
  * 获取验证码（jpg版本）
  * @param response
  */
 @RequestMapping(value="getJPGCode",method=RequestMethod.GET)
 public void getJPGCode(HttpServletResponse response,HttpServletRequest request){
  try {
  response.setHeader("Pragma", "No-cache"); 
  response.setHeader("Cache-Control", "no-cache"); 
  response.setDateHeader("Expires", 0); 
  response.setContentType("image/jpg"); 
  /**
  * jgp格式验证码
  * 宽，高，位数。
  */
  Captcha captcha = new SpecCaptcha(146,33,4);
  //输出
  captcha.out(response.getOutputStream());
  HttpSession session = request.getSession(true); 
  //存入Session
  session.setAttribute("_code",captcha.text().toLowerCase()); 
  } catch (Exception e) {
  LoggerUtils.fmtError(getClass(),e, "获取验证码异常：%s",e.getMessage());
  }
 }