获取请求主机IP

package com.sunll.common.util;

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 class NetworkUtil {

    public final static String getIpAddress(HttpServletRequest request) {
        // 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
        String ip = request.getHeader("X-Forwarded-For");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            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");
            }
            if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }

            //对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
        } else if (ip.length() > 15) {//"***.***.***.***".length() = 15
            String[] ips = ip.split(",");
            for (int index = 0; index < ips.length; index++) {
                String strIp = ips[index];
                if (!("unknown".equalsIgnoreCase(strIp))) {
                    ip = strIp;
                    break;
                }
            }
        }
        return ip;
    }
}