apollo-configservice/src/main/java/com/ctrip/framework/apollo/configservice/controller/ConfigController.java/ConfigController/tryToGetClientIp
class ConfigController:  private String tryToGetClientIp(HttpServletRequest request) {
    String forwardedFor = request.getHeader("X-FORWARDED-FOR");
    if (!Strings.isNullOrEmpty(forwardedFor)) {
      return X_FORWARDED_FOR_SPLITTER.splitToList(forwardedFor).get(0);
    }
    return request.getRemoteAddr();
  }