代理网页浏览器_建筑模板尺寸规格表_自己网站怎么推广_可以推广的软件有哪些

使用QT自带的MQTT模块部署客户端

在QT的.pro文件中加入MQTT模块：QT += mqtt

创建一个class专门用于MQTT客户端通讯

#include <QObject>
#include <QMqttClient>class MqttClient : public QObject
{Q_OBJECTpublic:explicit MqttClient(QObject *parent = nullptr);void connectToBroker(const QString &host, quint16 port);void publishMessage(const QString &topic, const QString &message);void subscribeToTopic(const QString &topic);private slots:void onConnected();void onMessageReceived(const QByteArray &message, const QMqttTopicName &topic);private:QMqttClient *m_client;
};

这个类定义了MQTT客户端常用到的几种操作：连接服务器(connectToBroker)，发布消息(publishMessage)，订阅消息(subscribeToTopic)。
然后还定义了两个信号槽函数：连接信号槽(onConnected)，用于抓取连接状态。onMessageReceived用于监听订阅消息。

class MqttClient的实现如下：

#include "mqttclient.h"
#include <QDebug>MqttClient::MqttClient(QObject *parent) : QObject(parent)
{m_client = new QMqttClient(this);connect(m_client, &QMqttClient::connected, this, &MqttClient::onConnected);connect(m_client, &QMqttClient::messageReceived, this, &MqttClient::onMessageReceived);
}void MqttClient::connectToBroker(const QString &host, quint16 port)
{m_client->setHostname(host);m_client->setPort(port);m_client->connectToHost();
}void MqttClient::publishMessage(const QString &topic, const QString &message)
{if (m_client->state() == QMqttClient::Connected) {m_client->publish(topic, message.toUtf8());} else {qDebug() << "MQTT客户端未连接";}
}void MqttClient::subscribeToTopic(const QString &topic)
{if (m_client->state() == QMqttClient::Connected) {m_client->subscribe(topic);} else {qDebug() << "MQTT客户端未连接";}
}void MqttClient::onConnected()
{qDebug() << "MQTT客户端已连接";
}void MqttClient::onMessageReceived(const QByteArray &message, const QMqttTopicName &topic)
{qDebug() << "接收到主题为" << topic.name() << "的消息:" << message;
}

使用QT在ui界面上生成按钮

在这里插入图片描述
连接到Broker按钮调用connectToBroker(const QString &host, quint16 port)

发布消息按钮调用publishMessage(const QString &topic, const QString &message)

Broker的主机IP地址，端口号，主题，消息内容全部可以从界面上获得。

在Windows上订阅相应主题测试

使用mosquitto for Windows 订阅，CMD命令mosquitto_sub -h 192.168.3.170 -p 1883 test/topic
在这里插入图片描述
然后在QT界面点击发布按钮，就能在Windows的订阅状态下看到发来的消息了。

在imx6ull上订阅Windows发布的消息

同样的操作，在QT上生成订阅按钮
在这里插入图片描述
订阅后在Windows上发布消息

正点原子开发板上显示的订阅到的信息

接收到主题为"test/topic" 的消息: "Hello Windows MQTT"