获取http请求的真实IP地址

/**
     * 获取http请求的真实IP地址 
     * @param request
     * @return
     */
    // cjianquan 2016/8/2
    public static String getIPAddr(HttpServletRequest request){
        if (request == null)
            return null;
        String ip = ("X-Forwarded-For");
        if (ip == null || () == 0 || "unknown".equalsIgnoreCase(ip))
            ip = ("Proxy-Client-IP");
        if (ip == null || () == 0 || "unknown".equalsIgnoreCase(ip))
            ip = ("WL-Proxy-Client-IP");
        if (ip == null || () == 0 || "unknown".equalsIgnoreCase(ip))
            ip = ("HTTP_CLIENT_IP");
        if (ip == null || () == 0 || "unknown".equalsIgnoreCase(ip))
            ip = ("HTTP_X_FORWARDED_FOR");
        if (ip == null || () == 0 || "unknown".equalsIgnoreCase(ip))
            ip = ();
        if ("127.0.0.1".equals(ip) || "0:0:0:0:0:0:0:1".equals(ip))
            try {
                ip = ().getHostAddress();
            }
            catch (UnknownHostException unknownhostexception) {
            }
        return ip;
    }