request.getParameter("captcha"); doFilterInternal

[lovehua]

rotected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) {

    String url = request.getRequestURI();
    if (pathMatcher.match(Constant.TOKEN_ENTRY_POINT_URL,url)){
        String captcha = request.getParameter("captcha");
        String randomStr = request.getParameter("randomStr");
        String username=request.getParameter("username");

     }

}

大神 无法获取到值是怎么 回事，新手请多指教