C++ MQTT客户端

下面是一个简单的ROS节点的C++ MQTT客户端的示例，包括.h和.cpp文件。

很抱歉，我之前提供的代码中似乎有一些错误。下面是更新后的代码，修复了mqtt命名空间中disconnect_response的问题：

mqtt_client.h：

#ifndef MQTT_CLIENT_H
#define MQTT_CLIENT_H#include <ros/ros.h>
#include <mqtt/async_client.h>class MqttClient
{
public:/*** @brief Constructor for MqttClient class.* @param serverURI The URI of the MQTT broker.* @param clientId The client ID to be used for connecting to the broker.* @param topic The MQTT topic to publish messages to.*/MqttClient(const std::string& serverURI, const std::string& clientId, const std::string& topic);/*** @brief Destructor for MqttClient class.*/~MqttClient();/*** @brief Connects to the MQTT broker.*/void connect();/*** @brief Disconnects from the MQTT broker.*/void disconnect();/*** @brief Publishes a message to the MQTT broker.* @param payload The payload of the message to be published.*/void publish(const std::string& payload);private:/*** @brief Callback function called when the MQTT client is connected to the broker.* @param responseCode The connect response code.*/void onConnect(int responseCode);/*** @brief Callback function called when the MQTT client is disconnected from the broker.* @param responseCode The disconnect response code.*/void onDisconnect(int responseCode);/*** @brief Callback function called when a message is published to the broker.* @param token The publish token.*/void onPublish(mqtt::delivery_token_ptr token);std::string serverURI_;      // URI of the MQTT brokerstd::string clientId_;       // Client ID for connecting to the brokerstd::string topic_;          // MQTT topic to publish messages tomqtt::async_client client_;  // MQTT clientmqtt::connect_options connOpts_;  // Connection options
};#endif // MQTT_CLIENT_H

mqtt_client.cpp：

#include "mqtt_client.h"MqttClient::MqttClient(const std::string& serverURI, const std::string& clientId, const std::string& topic): serverURI_(serverURI), clientId_(clientId), topic_(topic), client_(serverURI, clientId)
{connOpts_.set_keep_alive_interval(20);connOpts_.set_clean_session(true);
}MqttClient::~MqttClient()
{disconnect();
}void MqttClient::connect()
{try{mqtt::token_ptr conntok = client_.connect(connOpts_);conntok->wait();ROS_INFO("Connected to MQTT broker");}catch (const mqtt::exception& exc){ROS_ERROR("Failed to connect to MQTT broker: %s", exc.what());}
}void MqttClient::disconnect()
{try{mqtt::token_ptr disconntok = client_.disconnect();disconntok->wait();ROS_INFO("Disconnected from MQTT broker");}catch (const mqtt::exception& exc){ROS_ERROR("Failed to disconnect from MQTT broker: %s", exc.what());}
}void MqttClient::publish(const std::string& payload)
{try{mqtt::message_ptr pubmsg = mqtt::make_message(topic_, payload);pubmsg->set_qos(1);client_.publish(pubmsg)->wait();ROS_INFO("Published message: %s", payload.c_str());}catch (const mqtt::exception& exc){ROS_ERROR("Failed to publish message: %s", exc.what());}
}void MqttClient::onConnect(int responseCode)
{ROS_INFO("Connected to MQTT broker");
}void MqttClient::onDisconnect(int responseCode)
{ROS_INFO("Disconnected from MQTT broker");
}void MqttClient::onPublish(mqtt::delivery_token_ptr token)
{ROS_INFO("Published message");
}