String 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.getRemoteAddr();
    if (ip.equals("0:0:0:0:0:0:0:1") || ip.equals("127.0.0.1")) {
        /** 根據網絡卡取本機配置的IP */
        InetAddress inet = null;
        try {
            inet = InetAddress.getLocalHost();
            ip = inet.getHostAddress();
        } catch (UnknownHostException e) {
            logger.severe("IpHelper error." + e.toString());
        }
    }
}


/**
 * 對於通過多個代理的情況， 第一個IP為客戶端真實IP,多個IP按照','分割 "***.***.***.***".length() =
 * 15
 */
if (ip != null && ip.length() > 15) {
    if (ip.indexOf(",") > 0) {
        ip = ip.substring(0, ip.indexOf(","));
    }
}
return ip;