IP和数字相互转换函数

留着备份~

    public static String Ip2Number(String ip)
    {
        String[] segs = ip.split("\\.");
        long value = 0;
        for (int index = 0; index < segs.length; ++index)
        {
            value += Long.valueOf(segs[index]) << (24 - index *8);
        }

        return value + "";
    }

    public static String Number2Ip(String num)
    {
        long value = Long.valueOf(num);
        String ip = "";
        for (int index = 0;; ++index)
        {
            ip = ip + (value >> 24);
            value = (value - (value >> 24 << 24)) << 8;
            if (index >= 3)
            {
                break;
            }
            ip = ip + ".";
        }
        return ip;
    }