QString::arg()可用于固定长度输出

1.固定长度输出，适合用于串口通讯

 QString tem = QString("%1,%2,%3,%4,%5").arg(thr1, 3, 10, QChar("0")).arg(thr2,3, 10, QChar("0")).arg(thr3, 3, 10, QChar("0")).arg(thr4, 3, 10, QChar("0")).arg(thr5, 3, 10, QChar("0"));