获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址;

package com.utils;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * 获取请求主机IP地址,如果通过代理进来，则透过防火墙获取真实IP地址;
 * 
 */
public final class NetworkUtil {

    private static final Logger LOG = LoggerFactory.getLogger(NetworkUtil.class);

    public final static String getIpAddress(HttpServletRequest request)
            throws IOException {

        String ip = request.getHeader("X-Forwarded-For");

//        LOG.info("getIpAddress(HttpServletRequest) - X-Forwarded-For - String ip= {}" ,ip);

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            if (ip == null || ip.length() == 0
                    || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
//                LOG.info("getIpAddress(HttpServletRequest) - Proxy-Client-IP - String ip= {}" , ip);
            }
            if (ip == null || ip.length() == 0
                    || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
//                LOG.info("getIpAddress(HttpServletRequest) - WL-Proxy-Client-IP - String ip= {}" , ip);
            }
            if (ip == null || ip.length() == 0
                    || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
//                LOG.info("getIpAddress(HttpServletRequest) - HTTP_CLIENT_IP - String ip= {}" , ip);
            }
            if (ip == null || ip.length() == 0
                    || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
//                LOG.info("getIpAddress(HttpServletRequest) - HTTP_X_FORWARDED_FOR - String ip= {}" , ip);
            }
            if (ip == null || ip.length() == 0
                    || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
//                LOG.info("getIpAddress(HttpServletRequest) - getRemoteAddr - String ip= {}" , ip);
            }
        } else if (ip.length() > 15) {
            String[] ips = ip.split(",");
            for (int index = 0; index < ips.length; index++) {
                String strIp = (String) ips[index];
                if (!("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }
}