UUID是一长传字符串，可以确保是全局唯一，主要用于各种分布式算法。

The QUuid class stores a Universally Unique Identifier (UUID).

Using Universally Unique IDentifiers (UUID) is a standard way to uniquely identify entities in a distributed computing environment. A UUID is a 16-byte (128-bit) number generated by some algorithm that is meant to guarantee that the UUID will be unique in the distributed computing environment where it is used. The acronym GUID is often used instead, Globally Unique IDentifiers, but it refers to the same thing.

编程示例如下：

#include <QCoreApplication>
#include <QtCore>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    auto uuid=QUuid::createUuid();
    qDebug() << uuid.toString();
    return a.exec();
}

参考资料：

http://qt-project.org/doc/qt-5/QUuid.html

http://en.wikipedia.org/wiki/Universally_unique_identifier