判断是否是IP地址

static bool IsIP(QString IP)
    {
        QRegExp RegExp("((2[0-4]\\d|25[0-5]|[01]?\\d\\d?)\\.){3}(2[0-4]\\d|25[0-5]|[01]?\\d\\d?)");
        return RegExp.exactMatch(IP);
    }