从HTTP请求中获取客户IP地址

   /**
     * 从HTTP请求中获取客户IP地址
     *
     * @param request http请求
     * @return 客户IP地址
     */
    public static String getIPAddress( HttpServletRequest request )
    {
        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 = ();
        }
        return ip;
    }