mqtt协议的使用(AI 加工)

使用Spring Boot实现MQTT协议通常涉及几个关键步骤，这些步骤涵盖了从添加必要的依赖到配置客户端、处理消息的整个过程。以下是一个基本流程，包括了实现MQTT协议所需的必要步骤：

1. 添加依赖
首先，在pom.xml文件中添加Spring Integration和MQTT相关的依赖。

<dependencies>
    <!-- Spring Boot Starter for Integration -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-integration</artifactId>
    </dependency>
    <!-- Spring Integration MQTT Support -->
    <dependency>
        <groupId>org.springframework.integration</groupId>
        <artifactId>spring-integration-mqtt</artifactId>
        <version>5.4.3</version> <!-- 请确保版本与您的Spring Boot版本兼容 -->
    </dependency>
    <!-- Eclipse Paho MQTT Client -->
    <dependency>
        <groupId>org.eclipse.paho</groupId>
        <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
        <version>1.2.5</version> <!-- 请确保版本与您的需求兼容 -->
    </dependency>
</dependencies>

2. 配置属性

在application.yml或application.properties中配置MQTT相关的属性，如服务器地址、用户名、密码等。

Yaml

spring:
  mqtt:
    username: yourUsername
    password: yourPassword
    url: tcp://yourServerAddress:1883
    clientId: yourClientId
    topic: defaultTopic
    completionTimeout: 2000

3. 创建配置类
创建一个配置类来设置MqttPahoClientFactory和其他必要的bean。Java

import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;

@Configuration
@ConfigurationProperties(prefix = "spring.mqtt")
public class MqttConfiguration {

    private String username;
    private String password;
    private String url;
    private String clientId;
    private String topic = "TOPIC_DEFAULT";
    private Integer completionTimeout = 2000;

    // getters and setters

    @Bean
    public DefaultMqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        MqttConnectOptions options = new MqttConnectOptions();
        options.setCleanSession(true);
        options.setConnectionTimeout(0); // 无限等待
        options.setKeepAliveInterval(90);
        options.setAutomaticReconnect(true);
        options.setUserName(this.getUsername());
        options.setPassword(this.getPassword().toCharArray());
        options.setServerURIs(new String[]{this.getUrl()});
        factory.setConnectionOptions(options);
        return factory;
    }
}

4. 定义入站配置
定义一个配置类来设置消息通道（Channel）和入站适配器（Inbound Adapter），以便接收来自MQTT服务器的消息。Java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.handler.annotation.support.PayloadMethodArgumentResolver;

@Configuration
public class MqttInboundConfiguration {

    @Autowired
    private MqttConfiguration mqttConfig;
    @Autowired
    private DefaultMqttPahoClientFactory factory;
    @Autowired
    private MqttMessageReceiver mqttMessageReceiver;

    @Bean
    public MessageChannel mqttInBoundChannel() {
        return new DirectChannel();
    }

    @Bean
    public MqttPahoMessageDrivenChannelAdapter mqttInbound() {
        MqttPahoMessageDrivenChannelAdapter adapter =
                new MqttPahoMessageDrivenChannelAdapter(mqttConfig.getClientId(), factory, mqttConfig.getTopic());

        adapter.setCompletionTimeout(60000);
        adapter.setConverter(new DefaultPahoMessageConverter());
        adapter.setQos(0);
        adapter.setOutputChannel(mqttInBoundChannel());
        return adapter;
    }

    @Bean
    public PayloadMethodArgumentResolver payloadMethodArgumentResolver() {
        return new PayloadMethodArgumentResolver();
    }

    @Bean
    public MqttMessageReceiver mqttMessageHandler() {
        return this.mqttMessageReceiver;
    }
}

5. 消息处理器
创建一个消息处理器来处理接收到的消息。Java

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.integration.annotation.MessageEndpoint;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessagingException;

@MessageEndpoint
public class MqttMessageReceiver {

    private static final Logger log = LoggerFactory.getLogger(MqttMessageReceiver.class);

    @ServiceActivator(inputChannel = "mqttInBoundChannel")
    public void handleMessage(Message<?> message) throws MessagingException {
        String topic = (String) message.getHeaders().get("mqtt_receivedTopic");
        String payload = (String) message.getPayload();
        log.info("Received message from topic: {}, Payload: {}", topic, payload);
        // 处理接收到的消息
    }
}

6. 定义出站配置
如果需要发送消息给MQTT服务器，还需要定义出站配置。Java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
import org.springframework.messaging.MessageChannel;

@Configuration
public class MqttOutboundConfiguration {

    @Autowired
    private MqttConfiguration mqttConfig;
    @Autowired
    private DefaultMqttPahoClientFactory factory;

    @Bean
    public MessageChannel mqttOutboundChannel() {
        return new DirectChannel();
    }

    @Bean
    public MqttPahoMessageHandler mqttOutbound() {
        MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler(
                mqttConfig.getClientId() + "-out", factory);
        messageHandler.setDefaultTopic(mqttConfig.getTopic());
        messageHandler.setDefaultQos(0);
        messageHandler.setAsync(true);
        return messageHandler;
    }
}

7. 发送消息
创建一个服务类或接口来发送消息。Java

import org.springframework.integration.mqtt.support.MqttHeaders;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;

@Component
public class MqttMessageSender {

    private final MessageChannel mqttOutboundChannel;

    public MqttMessageSender(MessageChannel mqttOutboundChannel) {
        this.mqttOutboundChannel = mqttOutboundChannel;
    }

    public void send(String topic, String payload) {
        mqttOutboundChannel.send(MessageBuilder
            .withPayload(payload)
            .setHeader(MqttHeaders.TOPIC, topic)
            .build());
    }
}

通过以上步骤，您就可以在Spring Boot应用中实现MQTT协议的基本功能。这包括连接到MQTT代理、订阅主题、接收和处理消息以及发布消息。根据具体的应用场景，您可能还需要进一步定制和扩展这些配置。