MQTT实战之在vue和java中使用

在VUE中使用MQTT

1、创建vue项目（使用node版本为20.12.0）

>>npm create vite@latest
Need to install the following packages:
create-vite@6.1.1
Ok to proceed? (y) y
√ Project name: ... mqtt-vue
√ Select a framework: » Vue
√ Select a variant: » JavaScript

2、进入项目目录，安装依赖

npm install
npm install element-plus --save
npm install mqtt --save

3、在main.js

import { createApp } from 'vue'
import './style.css'
import App from './App.vue'
import ElementPlus from 'element-plus'
import 'element-plus/dist/index.css'

const app = createApp(App)
app.use(ElementPlus)
app.mount('#app')

4、在components文件目录下创建MqttDemo.vue

<script setup>
//消息质量取值数组
const qosList = [0,1,2]
</script>

<template>
    <div class="mqtt-demo">
        <el-card>
            <h3>配置信息</h3>
            <el-form label-position="top">
                <el-row :gutter="20">
                    <el-col :span="8">
                        <el-form-item prop="protocol" label="选择协议">
                            <el-select>
                                <el-option label="ws://" value="ws"></el-option>
                                <el-option label="wss://" value="wss"></el-option>
                            </el-select>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="host" label="主机地址">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="port" label="端口号">
                            <el-input type="number" placeholder="8083/8084"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="clientId" label="客户端ID">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="username" label="用户名">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="password" label="密码">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="24">
                        <el-button type="primary">建立连接</el-button>
                        <el-button type="danger">断开连接</el-button>
                    </el-col>
                </el-row>
            </el-form>
        </el-card>

        <el-card>
            <h3>订阅主题</h3>
            <el-form label-position="top">
                <el-row :gutter="20">
                    <el-col :span="8">
                        <el-form-item prop="topic" label="Topic">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-form-item prop="qos" label="Qos">
                            <el-select>
                                <el-option
                                    v-for="qos in qosList"
                                    :key="qos"
                                    :label="qos"
                                    :value="qos"></el-option>
                            </el-select>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-button type="primary" class="sub-btn">订阅主题</el-button>
                        <el-button type="primary" class="sub-btn">取消订阅</el-button>
                    </el-col>
                </el-row>
            </el-form>
        </el-card>

        <el-card>
            <h3>发布消息</h3>
            <el-form label-position="top">
                <el-row :gutter="20">
                    <el-col :span="8">
                        <el-form-item prop="topic" label="Topic">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-form-item prop="payload" label="Payload">
                            <el-input></el-input>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-form-item prop="qos" label="Qos">
                            <el-select>
                                <el-option
                                    v-for="qos in qosList"
                                    :key="qos"
                                    :label="qos"
                                    :value="qos"></el-option>
                            </el-select>
                        </el-form-item>
                    </el-col>
                </el-row>
            </el-form>
            <el-col :span="24" class="text-right">
                <el-button type="primary">发布消息</el-button>
            </el-col>
        </el-card>

        <el-card>
            <h3>接收到的消息</h3>
            <el-col :span="24">
                <el-input
                    type="textarea"
                    :rows="3"
                    readonly></el-input>
            </el-col>
        </el-card>
    </div>
</template>

5、在App.vue中

<script setup>
import MqttDemo from './components/MqttDemo.vue'
</script>

<template>
  <MqttDemo />
</template>
<style scoped>

</style>

6、建立-断开连接

<script setup>
import {ref} from 'vue';
import mqtt from 'mqtt';
//消息质量取值数组
const qosList = [0,1,2];

//定义连接参数的对象
const connectionInfo = ref({
    protocol:'ws',
    host:'127.0.0.1',
    port:'8083',
    clientId:'emqx_vue_client_'+Math.random().toString().substring(2,8),
    username:'user',
    password:'123456'
})

//建立连接
const clientInitData = ref({
    connected: false
})
const client = ref({})
const createConnection = () => {
    const { protocol, host, port, clientId, ...options } = connectionInfo.value
    const connectionUrl = `${protocol}://${host}:${port}/mqtt`
    client.value = mqtt.connect(connectionUrl,options)
    clientInitData.value.connected = true
}

//断开连接
const closeConnection = () =>{
    client.value.end(false,()=>{
        clientInitData.value.connected = false;
    })
}

</script>

============================================================================================================

<el-card>
            <h3>配置信息</h3>
            <el-form label-position="top">
                <el-row :gutter="20">
                    <el-col :span="8">
                        <el-form-item prop="protocol" label="选择协议">
                            <el-select v-model="connectionInfo.protocol">
                                <el-option label="ws://" value="ws"></el-option>
                                <el-option label="wss://" value="wss"></el-option>
                            </el-select>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="host" label="主机地址">
                            <el-input v-model="connectionInfo.host"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="port" label="端口号">
                            <el-input type="number" v-model="connectionInfo.port" placeholder="8083/8084"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="clientId" label="客户端ID">
                            <el-input v-model="connectionInfo.clientId"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="username" label="用户名">
                            <el-input v-model="connectionInfo.username"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="8">
                        <el-form-item prop="password" label="密码">
                            <el-input v-model="connectionInfo.password"></el-input>
                        </el-form-item>
                    </el-col>

                    <el-col :span="24">
                        <el-button type="primary" :disabled="clientInitData.connected" @click="createConnection">建立连接</el-button>
                        <el-button type="danger" :disabled="!clientInitData.connected" @click="closeConnection">断开连接</el-button>
                    </el-col>
                </el-row>
            </el-form>
        </el-card>

7、订阅主题-取消订阅

import { ElMessage } from 'element-plus'

//订阅主题对象
const subscriptionInfo = ref({
    topic:'',
    qos: 0
})

//接收消息对象
const receiverMessages = ref({})
const subscriptionInitData = ref({
    subscription: false
})

//订阅主题
const subscriptionTopicHandler = () =>{
    const { topic, qos } = subscriptionInfo.value
    client.value.subscribe(topic, { qos }, (error, res) => {
        if(error){
            ElMessage.error("订阅主题失败")
            return ;
        }

        subscriptionInitData.value.subscription=true

        //给连接对象注册接收消息的事件
        client.value.on('message',(topic, message)=>{
            receiverMessages.value = topic + "------>" + message
        })
        ElMessage({
            message: '订阅主题成功',
            type: 'success',
        })
    })
}

//取消订阅
const unSubscriptionTopicHandler = () => {
    const { topic, qos } = subscriptionInfo.value
    client.value.unsubscribe(topic, { qos }, (error, res)=>{
        if(error){
            ElMessage.error("取消主题订阅失败")
            return ;
        }
        subscriptionInitData.value.subscription = false;
        ElMessage({
            message: '取消订阅成功',
            type: 'success',
        })
    })
}

============================================================================================================

<el-card>
            <h3>订阅主题</h3>
            <el-form label-position="top">
                <el-row :gutter="20">
                    <el-col :span="8">
                        <el-form-item prop="topic" label="Topic">
                            <el-input v-model="subscriptionInfo.topic"></el-input>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-form-item prop="qos" label="Qos">
                            <el-select v-model="subscriptionInfo.qos">
                                <el-option
                                    v-for="qos in qosList"
                                    :key="qos"
                                    :label="qos"
                                    :value="qos"></el-option>
                            </el-select>
                        </el-form-item>
                    </el-col>
                    <el-col :span="8">
                        <el-button type="primary" class="sub-btn" :disabled="subscriptionInitData.subscription" @click="subscriptionTopicHandler">订阅主题</el-button>
                        <el-button type="primary" class="sub-btn" :disabled="!subscriptionInitData.subscription" @click="unSubscriptionTopicHandler">取消订阅</el-button>
                    </el-col>
                </el-row>
            </el-form>
        </el-card>

8、发布消息

//发送消息对象
const publishInfo= ref({
    topic: '',
    qos: 0,
    payload: ''
})

//发布消息
const doPublish = () =>{
    const { topic, qos, payload } = publishInfo.value
    client.value.publish(topic, payload, { qos }, (error, res) => {
        if(error){
            ElMessage.error("发布消息失败")
            return;
        }
        ElMessage({
            message: '发布消息成功',
            type: 'success',
        })
    })
}

============================================================================================================

<el-card>
    <h3>发布消息</h3>
    <el-form label-position="top">
        <el-row :gutter="20">
            <el-col :span="8">
                <el-form-item prop="topic" label="Topic">
                    <el-input v-model="publishInfo.topic"></el-input>
                </el-form-item>
            </el-col>
            <el-col :span="8">
                <el-form-item prop="payload" label="Payload">
                    <el-input v-model="publishInfo.payload"></el-input>
                </el-form-item>
            </el-col>
            <el-col :span="8">
                <el-form-item prop="qos" label="Qos">
                    <el-select v-model="publishInfo.qos">
                        <el-option
                            v-for="qos in qosList"
                            :key="qos"
                            :label="qos"
                            :value="qos"></el-option>
                    </el-select>
                </el-form-item>
            </el-col>
        </el-row>
    </el-form>
    <el-col :span="24" class="text-right">
        <el-button type="primary" @click="doPublish">发布消息</el-button>
    </el-col>
</el-card>

<el-card>
    <h3>接收到的消息</h3>
    <el-col :span="24">
        <el-input v-model="receiverMessages"
            type="textarea"
            :rows="3"
            readonly></el-input>
    </el-col>
</el-card>

在java中使用MQTT

方式一：eclipse.paho.client.mqttv3

1、创建springboot项目，添加依赖

<!--        mqtt客户端依赖项-->
        <dependency>
            <groupId>org.eclipse.paho</groupId>
            <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
            <version>1.2.0</version>
        </dependency>

2、建立连接

public void createConnection() throws MqttException {
        //定义连接相关参数
        String serverURI = "tcp://127.0.0.1:1883";
        String clientId = "pacho_client_123";

       //创建MqttClient对象
        MqttClient mqttClient = new MqttClient(serverURI, clientId, new MemoryPersistence());

        //创建MqttConnectOptions对象
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName("user");
        mqttConnectOptions.setPassword("123456".toCharArray());
        mqttConnectOptions.setCleanSession(true);

        //发送建立连接的请求
        mqttClient.connect(mqttConnectOptions);

        //让当前方法处于阻塞状态
        while (true);
    }

3、发送消息

public void sendMsg() throws MqttException {
        //定义连接相关参数
        String serverURI = "tcp://127.0.0.1:1883";
        String clientId = "pacho_client_123";

        //创建MqttClient对象
        MqttClient mqttClient = new MqttClient(serverURI, clientId, new MemoryPersistence());

        //创建MqttConnectOptions对象
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName("user");
        mqttConnectOptions.setPassword("123456".toCharArray());
        mqttConnectOptions.setCleanSession(true);

        //发送建立连接的请求
        mqttClient.connect(mqttConnectOptions);

        //发送消息对象
        MqttMessage mqttMessage = new MqttMessage();
        mqttMessage.setPayload("hello mqtt java client".getBytes(StandardCharsets.UTF_8));

        mqttClient.publish("aa",mqttMessage);   //主题，发送的消息

        //关闭连接
        mqttClient.disconnect();
        mqttClient.close();
    }

4、订阅主题、接收消息

public void receiveMsg() throws MqttException {
        //定义连接相关参数
        String serverURI = "tcp://127.0.0.1:1883";
        String clientId = "pacho_client_123";

        //创建MqttClient对象
        MqttClient mqttClient = new MqttClient(serverURI, clientId, new MemoryPersistence());

        //创建MqttConnectOptions对象
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName("user");
        mqttConnectOptions.setPassword("123456".toCharArray());
        mqttConnectOptions.setCleanSession(true);

        mqttClient.setCallback(new MqttCallback() {
            @Override
            public void connectionLost(Throwable throwable) {    //连接丢失时执行
                System.out.println("connect lose...");
            }

            @Override
            public void messageArrived(String topic, MqttMessage mqttMessage) throws Exception {     //消息接收时执行
                System.out.println("topic--->"+topic);
                byte[] payload = mqttMessage.getPayload();
                System.out.println("msg--->"+new String(payload));
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken iMqttDeliveryToken) {      //消息接收完毕后执行
                System.out.println("delivery complete...");
            }
        });

        //发送建立连接的请求
        mqttClient.connect(mqttConnectOptions);

        //订阅主题
        mqttClient.subscribe("aa",2);

当给主题为aa发送消息时，运行结果显示

topic--->aa

msg--->{

        "msg": "aaacccc"

}

方式二：spring-integration-mqtt

1、创建springboot项目，添加依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>mqtt-java</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mqtt-java</name>
    <description>mqtt-java</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--        springboot集成中间件的基础依赖-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-integration</artifactId>
        </dependency>

<!--        springboot集成mqtt客户端的依赖-->
        <dependency>
            <groupId>org.springframework.integration</groupId>
            <artifactId>spring-integration-mqtt</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.76</version>
        </dependency>
    </dependencies>

</project>

2、在application.yml中添加mqtt的配置信息

spring:
  mqtt:
    username: user
    password: 123456
    url: tcp://127.0.0.1:1883
    subClientId: sub_client_id_123
    subTopic: java/aa
    pubClientId: pub_client_id_123

3、添加读取mqtt配置信息的配置类MqttConfigurationProperties

package com.example.mqttjava;

import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;

@Data
@ConfigurationProperties(prefix="spring.mqtt")
public class MqttConfigurationProperties {
    private String username;
    private String password;
    private String url;
    private String subClientId;
    private String subTopic;
    private String pubClientId;
}

4、在启动类MqttJavaApplication中添加读取配置信息的注解

package com.example.mqttjava;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;

@SpringBootApplication
@EnableConfigurationProperties(value = MqttConfigurationProperties.class)
public class MqttJavaApplication {

    public static void main(String[] args) {
        SpringApplication.run(MqttJavaApplication.class, args);
    }

}

5、配置MQTT客户端连接工厂类MqttConfiguration

package com.example.mqttjava;

import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
import org.springframework.integration.mqtt.core.MqttPahoClientFactory;

@Configuration
public class MqttConfiguration {
    @Autowired
    private MqttConfigurationProperties mqttConfigurationProperties;

    @Bean
    public MqttPahoClientFactory mqttPahoClientFactory(){
        DefaultMqttPahoClientFactory mqttPahoClientFactory = new DefaultMqttPahoClientFactory();
        MqttConnectOptions options = new MqttConnectOptions();
        options.setCleanSession(true);
        options.setUserName(mqttConfigurationProperties.getUsername());
        options.setPassword(mqttConfigurationProperties.getPassword().toCharArray());
        options.setServerURIs(new String[]{mqttConfigurationProperties.getUrl()});
        mqttPahoClientFactory.setConnectionOptions(options);
        return mqttPahoClientFactory;
    }
}

6、MQTT消息入站处理类MqttInboundConfiguration

首先创建一个消息通道，设置一个MQTT入栈适配器来订阅特定的主题并接收消息，然后将这些消息发送到消息通道，最后由指定的消息处理器来处理这些消息

package com.example.mqttjava;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.core.MessageProducer;
import org.springframework.integration.mqtt.core.MqttPahoClientFactory;
import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
import org.springframework.integration.mqtt.support.DefaultPahoMessageConverter;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;


@Configuration
public class MqttInboundConfiguration {
    @Autowired
    private MqttConfigurationProperties mqttConfigurationProperties;

    @Autowired
    private MqttPahoClientFactory mqttPahoClientFactory;

    @Autowired
    private ReceiverMessageHandler receiverMessageHandler;

    //消息通道
    @Bean
    public MessageChannel messageInboundChannel(){
        return new DirectChannel();
    }

    //配置入站适配器：设置要订阅的主题，指定消息相关属性
    @Bean
    public MessageProducer messageProducer(){
        MqttPahoMessageDrivenChannelAdapter mqttPahoMessageDrivenChannelAdapter = new MqttPahoMessageDrivenChannelAdapter(
                mqttConfigurationProperties.getUrl(),
                mqttConfigurationProperties.getSubClientId(),
                mqttPahoClientFactory,
                mqttConfigurationProperties.getSubTopic().split(",")
        );

        mqttPahoMessageDrivenChannelAdapter.setQos(1);
        mqttPahoMessageDrivenChannelAdapter.setConverter(new DefaultPahoMessageConverter());
        mqttPahoMessageDrivenChannelAdapter.setOutputChannel(messageInboundChannel());
        return mqttPahoMessageDrivenChannelAdapter;
    }

    @Bean
    @ServiceActivator(inputChannel = "messageInboundChannel")
    public MessageHandler messageHandler(){
        return  receiverMessageHandler;
    }
}

7、接收MQTT消息处理器ReceiverMessageHandler

package com.example.mqttjava;

import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.MessagingException;
import org.springframework.stereotype.Component;


@Component
public class ReceiverMessageHandler implements MessageHandler {

    @Override
    public void handleMessage(Message<?> message) throws MessagingException {
        Object payload = message.getPayload();
        System.out.println("payload:  "+payload);
        System.out.println("message:  "+message);
        MessageHeaders headers = message.getHeaders();
        String topicName = headers.get("mqtt_receivedTopic").toString();
        System.out.println("topicName: "+topicName);
    }
}

输出：

payload:  {
  "msg": "aaacccc"
}
message:  GenericMessage [payload={
  "msg": "aaacccc"
}, headers={mqtt_receivedRetained=true, mqtt_id=0, mqtt_duplicate=false, id=873967f5-6a6f-c092-f276-62ed1b1d3c18, mqtt_receivedTopic=java/aa, mqtt_receivedQos=0, timestamp=1738572747948}]
topicName: java/aa

8、MQTT消息出站处理类MqttOutboundConfiguration

• @ServiceActivator(inputChannel = "mqttOutboundChannel")：这个注解将mqttOutBoundMessageHandler标记为一个服务激活器，并将其与mqttOutboundChannel消息通道关联起来。这意味着，当消息被发送到mqttOutboundChannel时，mqttOutBoundMessageHandler将负责处理这些消息（即将它们发送到MQTT代理）。

package com.example.mqttjava;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.core.MessageProducer;
import org.springframework.integration.mqtt.core.MqttPahoClientFactory;
import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
import org.springframework.integration.mqtt.support.DefaultPahoMessageConverter;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;


@Configuration
public class MqttOutboundConfiguration {
    @Autowired
    private MqttConfigurationProperties mqttConfigurationProperties;

    @Autowired
    private MqttPahoClientFactory mqttPahoClientFactory;

    //配置消息通道
    @Bean
    public MessageChannel mqttOutboundChannel(){
        return new DirectChannel();
    }

    //配置出站消息处理器
    @Bean
    @ServiceActivator(inputChannel = "mqttOutboundChannel")
    public MessageHandler mqttOutBoundMessageHandler(){
        MqttPahoMessageHandler mqttPahoMessageHandler = new MqttPahoMessageHandler(
                mqttConfigurationProperties.getUrl(),
                mqttConfigurationProperties.getPubClientId(),
                mqttPahoClientFactory
        );
        mqttPahoMessageHandler.setDefaultQos(0);
        mqttPahoMessageHandler.setDefaultTopic("default");
        mqttPahoMessageHandler.setAsync(true);
        return mqttPahoMessageHandler;
    }

}

9、MQTT网关接口MqttGateway，用于向MQTT发送消息

package com.example.mqttjava;

import org.springframework.context.annotation.Bean;
import org.springframework.integration.annotation.MessagingGateway;
import org.springframework.integration.mqtt.support.MqttHeaders;
import org.springframework.messaging.handler.annotation.Header;
import org.springframework.stereotype.Component;

@Component
@MessagingGateway(defaultRequestChannel = "mqttOutboundChannel")
public interface MqttGateway {
    public abstract void sendMsgToMqtt(@Header(value = MqttHeaders.TOPIC) String topic, String payload);

    public abstract void sendMsgToMqtt(@Header(value = MqttHeaders.TOPIC) String topic, @Header(value = MqttHeaders.QOS) int qos, String payload);
}

10、向MQTT发送消息的服务类MqttMessageSender

package com.example.mqttjava;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class MqttMessageSender {
    @Autowired
    private MqttGateway mqttGateway;

    public void sendMsg(String topic, String msg){
        mqttGateway.sendMsgToMqtt(topic,msg);
    }

    public void sendMsg(String topic, int qos, String msg){
        mqttGateway.sendMsgToMqtt(topic, qos, msg);
    }
}

11、发送消息测试

package com.example.mqttjava;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest(classes = MqttJavaApplication.class)
public class MqttTest {
    @Autowired
    private MqttMessageSender mqttMessageSender;

    @Test
    public void sendToMsg(){
        mqttMessageSender.sendMsg("java/aa","hello");
    }
}

payload:  hello
message:  GenericMessage [payload=hello, headers={mqtt_receivedRetained=false, mqtt_id=0, mqtt_duplicate=false, id=35e8e42b-cc22-f4df-8ba1-b184616ded03, mqtt_receivedTopic=java/aa, mqtt_receivedQos=0, timestamp=1738572748073}]
topicName: java/aa