qt 学习小节

字符串转化成字节序列
QString------->QByteArray

1）
QByteArray QString::toLatin1() const
Returns a Latin-1 representation of the string as a QByteArray.

The returned byte array is undefined if the string contains non-Latin1 characters. Those characters may be suppressed or replaced with a question mark.
2）
QByteArray bytes = QByteArray::fromHex("010304000008");

qDebug("%#x",bytes.at(1));// 03

QByteArray QByteArray::fromHex(const QByteArray & hexEncoded) [static]
Returns a decoded copy of the hex encoded array hexEncoded. Input is not checked for validity; invalid characters in the input are skipped, enabling the decoding process to continue with subsequent characters.

For example:

QByteArray text = QByteArray::fromHex("517420697320677265617421");
text.data();            // returns "Qt is great!"