服务器 获取 客户端的真实IP

 /**
  * 
  * @param request
  * @return 请求IP地址
  */
 public static String getIp(HttpServletRequest request) {
  //
  String ip = null;
  //
  ip = request.getHeader("X-Forwarded-For");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  //
  ip = request.getHeader("Proxy-Client-IP");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  //
  ip = request.getHeader("WL-Proxy-Client-IP");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  //
  ip = request.getHeader("HTTP_CLIENT_IP");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  //
  ip = request.getHeader("HTTP_X_FORWARDED_FOR");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  //
  ip = request.getParameter("__fromReferIP");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  // NGINX用
  ip = request.getHeader("X-Real-IP");
  if (isRealIP(ip)) {
   return getRealIp(ip);
  }
  ip = request.getRemoteAddr();
  //
  return ip;
 }

 /**
  * @param ip
  * @return
  */
 private static boolean isRealIP(String ip) {
  return StringUtils.isNotBlank(ip) && !"unknown".equalsIgnoreCase(ip);
 }

 /**
  * @param ip
  * @return
  */
 private static String getRealIp(String ip) {
  //
  if (ip.indexOf(",") != -1) {
   return StringUtils.left(ip.split(",")[0], 15);

  }
  return ip;
 }