Server gets client IP tool class: IPUtil

I. Overview

 

    Get the client Ip tool class, support the case of proxy between client and server

 

two code

 

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang3.StringUtils;

/**
 * Get client ip
 */
public class IpUtil {

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


    /**
     * Get client ip
     * @param request http request
     * @return client ip (ipv4 or ipv6)
     */
    public static String getClientIp(HttpServletRequest request) {

        String clientIp = getIpFromHttpHeader(request);
        if (StringUtils.isNotEmpty(clientIp)) {
            return clientIp;
        }

        return request.getRemoteAddr();
    }

    //Get ip from http header for priority support with proxy
    private static String getIpFromHttpHeader(HttpServletRequest request) {
        for (String header : CONTAINS_IP_HEADERS) {
            String clientIps = request.getHeader(header);

            if (StringUtils.isEmpty(clientIps)) {
                continue;
            }

            if (StringUtils.equalsIgnoreCase("unknown", clientIps)) {
                continue;
            }

            //According to the proxy protocol, take the first one as the client ip
            if (!StringUtils.contains(clientIps, ",")) {
                return clientIps;
            }

            String[] ips = StringUtils.split(clientIps, ',');
            return ips[0];

        }
        return null;
    }

}