How to get Client's IP address in Java? Request.getRemoteAddr() returns IP address of the machine on which Tomcat server is running

问题

I am using the following code to get the Client's Ip Address. But for all the headers, i am getting null value. And request.getRemoteAddr() returns IP address of the machine on which Tomcat server is running. So, what is the efficient way to get the IP address of the machine from which request is coming ?

    private static final String[] HEADERS_TO_TRY = { 
      "X-Forwarded-For",
      "Proxy-Client-IP",
      "WL-Proxy-Client-IP",
      "HTTP_X_FORWARDED_FOR",
      "HTTP_X_FORWARDED",
      "HTTP_X_CLUSTER_CLIENT_IP",
      "HTTP_CLIENT_IP",
      "HTTP_FORWARDED_FOR",
      "HTTP_FORWARDED",
      "HTTP_VIA",
      "REMOTE_ADDR" };

    public static String getClientIpAddress(HttpServletRequest request) {
      for (String header : HEADERS_TO_TRY) {
        String ip = request.getHeader(header);
        if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {
            return ip;
        }
    }
    return request.getRemoteAddr();
   }

来源：https://stackoverflow.com/questions/25403343/how-to-get-clients-ip-address-in-java-request-getremoteaddr-returns-ip-addre