code: @Sensitive
      public static String getHeader(HttpServletRequest req, String key) {
          HttpServletRequest sr = getWrappedServletRequestObject(req);
          return sr.getHeader(key);
      }
docs: Obtain the value of the specified header.
  
  @param req
  @param key
  @return The value of the header
  @see HttpServletRequest#getHeader(String)