java通过request对象获取用户IP地址

package com.test.util;

import java.net.InetAddress;
import javax.servlet.http.HttpServletRequest;
import org.apache.commons.lang3.StringUtils;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class IPUtils {

	private static final String IP_UTILS_FLAG = ",";
    private static final String UNKNOWN = "unknown";
    private static final String LOCALHOST_IP = "0:0:0:0:0:0:0:1";
    private static final String LOCALHOST_IP1 = "127.0.0.1";

    /**
     * 获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     */
    public static String getIpAddress(HttpServletRequest request) {
        //以下两个获取在k8s中，将真实的客户端IP，放到了x-Original-Forwarded-For。而将WAF的回源地址放到了 x-Forwarded-For了。
        String ip = request.getHeader("X-Original-Forwarded-For");
        if (StringUtils.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Forwarded-For");
        }
        //获取nginx等代理的ip
        if (StringUtils.isEmpty(ip) || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("x-forwarded-for");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_CLIENT_IP");
        }
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }
        //兼容k8s集群获取ip
        if (ip == null || ip.length() == 0 || UNKNOWN.equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
            if (LOCALHOST_IP1.equalsIgnoreCase(ip) || LOCALHOST_IP.equalsIgnoreCase(ip)) {
                //根据网卡取本机配置的IP
                InetAddress iNet = null;
                try {
                    iNet = InetAddress.getLocalHost();
                } catch (Exception e) {
                    log.error("getClientIp error: {}", e);
                }
                ip = iNet.getHostAddress();
            }
        }

        //使用代理，则获取第一个IP地址
        if (!StringUtils.isEmpty(ip) && ip.indexOf(IP_UTILS_FLAG) > 0) {
            ip = ip.substring(0, ip.indexOf(IP_UTILS_FLAG));
        }
        return ip;
    }
    
}