qt实现mqtt服务端源码

以下是使用Qt实现MQTT服务端的基本代码示例：

#include <QtMqtt/QtMqtt>
#include <QtCore/QCoreApplication>

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);

    QMqttServer server;
    if (!server.listen(QHostAddress::Any, 1883)) {
        qCritical("Failed to bind to port 1883.");
        return 1;
    }

    QObject::connect(&server, &QMqttServer::clientConnected, [](const QString &clientID) {
        qDebug("Client connected: %s", qPrintable(clientID));
    });

    QObject::connect(&server, &QMqttServer::clientDisconnected, [](const QString &clientID) {
        qDebug("Client disconnected: %s", qPrintable(clientID));
    });

    QObject::connect(&server, &QMqttServer::messageReceived, [](const QByteArray &message, const QMqttTopicName &topic) {
        qDebug("Received message on topic %s: %s", qPrintable(topic.name()), message.constData());
    });

    return app.exec();
}

这个示例代码使用了Qt的QMqttServer类来实现MQTT服务器。它监听来自任何IP地址的1883端口的连接，并打印出连接和断开连接的客户端的ID。它还打印出在主题上收到的消息。您可以根据需要修改此示例代码，以实现更高级的MQTT服务端功能。