code: protected NaviRpcExporter getRpcExporter(HttpServletRequest httpServletRequest) {
          String context = httpServletRequest.getPathInfo();
          if (context == null) {
              throw new InvalidRequestException("Rpc path invalid");
          }
          if (context.length() > 0) {
              context = context.substring(1);
          }
          NaviRpcExporter serviceExporter = serviceLocator.getService(context);
          if (serviceExporter == null) {
              throw new ServiceNotFoundException("No rpc service found for " + context);
          }
          return serviceExporter;
      }
docs: 从http请求request path中获取<tt>NaviRpcExporter</tt>，起到路由作用
  
  @param httpServletRequest
  @return