Spring Boot使用MQTT与硬件设备进行交互

Spring Boot需要与硬件设备进行交互,使用MQTT作为通信协议。对于这种情况,MQTT的服务端(Broker)需要在服务器上安装和配置,硬件设备和Java应用程序(Spring Boot)通过该Broker进行消息的发布和订阅。以下是详细步骤:

一、服务器安装步骤

安装 Mosquitto (MQTT Broker)

Ubuntu:

# 更新软件包列表
sudo apt-get update
# 安装 Mosquitto 及其客户端工具
sudo apt-get install mosquitto mosquitto-clients
# 配置 Mosquitto 开机自启动
sudo systemctl enable mosquitto
# 启动 Mosquitto 服务
sudo systemctl start mosquitto

CentOS:

# 更新软件包列表
sudo yum update
# 安装 EPEL 仓库
sudo yum install epel-release
# 安装 Mosquitto
sudo yum install mosquitto
# 配置 Mosquitto 开机自启动
sudo systemctl enable mosquitto
# 启动 Mosquitto 服务
sudo systemctl start mosquitto

配置 Mosquitto(可选)

默认情况下,Mosquitto 允许匿名连接,但为了安全性,可以配置用户名和密码。在 /etc/mosquitto/mosquitto.conf 文件中进行配置:

# 启用监听1883端口
listener 1883
# 允许匿名访问
allow_anonymous true

二、Spring Boot 配置和工具类

添加依赖

pom.xml文件中添加以下依赖:

<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-mqtt</artifactId>
</dependency>
<dependency>
    <groupId>org.eclipse.paho</groupId>
    <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
</dependency>

application.yml配置

可以将所有MQTT相关的配置,包括client_id默认主题,配置在application.yml

mqtt:
  broker:
    # 设备MQTT应用配置
    url: tcp://your_server_ip:1883
    username: your_username
    password: your_password
    # 自定义约定client_id
    clientId: your_client_id
  topics:
    # 默认监听
    default: your/default_topic
    # 自定义监听
    subscriptions:
      - your/topic1
      - your/topic2

配置类

创建一个 MqttConfig 配置类:

import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.springframework.beans.factory.annotation.Value;
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.DefaultMqttPahoClientFactory;
import org.springframework.integration.mqtt.core.MqttPahoClientFactory;
import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.beans.factory.annotation.Autowired;

@Configuration
public class MqttConfig {

    @Autowired
    private MqttUtil mqttUtil;

    @Value("${mqtt.broker.url}")
    private String brokerUrl;

    @Value("${mqtt.broker.username}")
    private String username;

    @Value("${mqtt.broker.password}")
    private String password;

    @Value("${mqtt.broker.clientId}")
    private String clientId;

    @Value("${mqtt.topics.default}")
    private String defaultTopic;

    @Value("${mqtt.topics.subscriptions}")
    private String[] topics;

    // 配置MQTT客户端工厂
    @Bean
    public MqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        MqttConnectOptions options = new MqttConnectOptions();
        options.setServerURIs(new String[]{brokerUrl});
        options.setUserName(username);
        options.setPassword(password.toCharArray());
        factory.setConnectionOptions(options);
        return factory;
    }

    // (接收消息:步骤一)定义一个消息通道,用于接收消息
    @Bean
    public MessageChannel mqttInputChannel() {
        return new DirectChannel();
    }

    // (接收消息:步骤二)配置消息驱动通道适配器,用于接收指定主题的消息
    @Bean
    public MessageProducer inbound() {
        MqttPahoMessageDrivenChannelAdapter adapter =
                new MqttPahoMessageDrivenChannelAdapter(clientId, mqttClientFactory(), topics);
        adapter.setOutputChannel(mqttInputChannel());
        return adapter;
    }

    // (接收消息:步骤三)配置消息处理器,用于处理接收到的消息
    @Bean
    @ServiceActivator(inputChannel = "mqttInputChannel")
    public MessageHandler handler() {
        return message -> {
            String topic = message.getHeaders().get("mqtt_receivedTopic").toString();
            String payload = message.getPayload().toString();
            System.out.println("接收到消息: 主题 = " + topic + ", 内容 = " + payload);

            // 发布接收到的消息事件
            mqttUtil.publishReceivedMessage(topic, payload);
        };
    }

    // 配置MQTT消息发送处理器
    @Bean
    @ServiceActivator(inputChannel = "mqttOutboundChannel")
    public MessageHandler mqttOutbound() {
        MqttPahoMessageHandler messageHandler =
                new MqttPahoMessageHandler(clientId, mqttClientFactory());
        messageHandler.setAsync(true);
        messageHandler.setDefaultTopic(defaultTopic); // 设置默认主题
        return messageHandler;
    }

    // 定义一个消息通道,用于发送消息
    @Bean
    public MessageChannel mqttOutboundChannel() {
        return new DirectChannel();
    }
}

MQTT 工具类
创建一个 MqttUtil 工具类:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;

@Component
public class MqttUtil {

    @Autowired
    private MessageChannel mqttOutboundChannel;

    @Autowired
    private ApplicationEventPublisher eventPublisher;

    /**
     * 发送消息到默认主题
     * @param payload 消息内容
     */
    public void sendMessage(String payload) {
        mqttOutboundChannel.send(MessageBuilder.withPayload(payload).build());
    }

    /**
     * 发送消息到指定主题
     * @param topic 主题
     * @param payload 消息内容
     */
    public void sendMessage(String topic, String payload) {
        mqttOutboundChannel.send(MessageBuilder.withPayload(payload)
                .setHeader("mqtt_topic", topic)
                .build());
    }

    /**
     * (接收消息:步骤四)发布接收到的MQTT消息事件
     * @param topic 主题
     * @param payload 消息内容
     */
    public void publishReceivedMessage(String topic, String payload) {
        MqttMessageEvent event = new MqttMessageEvent(this, topic, payload);
        eventPublisher.publishEvent(event);
    }
}

MQTT 消息事件( MqttUtil.publishReceivedMessage() 方法使用)

创建一个事件类,用于封装接收到的MQTT消息:

import org.springframework.context.ApplicationEvent;

public class MqttMessageEvent extends ApplicationEvent {

    private final String topic;
    private final String payload;

    public MqttMessageEvent(Object source, String topic, String payload) {
        super(source);
        this.topic = topic;
        this.payload = payload;
    }

    public String getTopic() {
        return topic;
    }

    public String getPayload() {
        return payload;
    }
}

消息监听器( MqttUtil.publishReceivedMessage() 方法使用)

创建一个监听器,用于处理接收到的MQTT消息:

import org.springframework.context.event.EventListener;
import org.springframework.stereotype.Component;

@Component
public class MqttMessageListener {
    /** 
     * (接收消息:步骤五)事件监听器中处理消息 
     *     说明:此方法将接收到上方 MqttUtil.publishReceivedMessage() 发布的事件并处理这些消息 
     * @param event 接收到的事件 
     */

    @EventListener
    public void handleMqttMessage(MqttMessageEvent event) {
        String topic = event.getTopic();
        String payload = event.getPayload();
        System.out.println("处理接收到的消息: 主题 = " + topic + ", 内容 = " + payload);

        // 根据不同的主题进行不同的处理
        if ("your/topic1".equals(topic)) {
            handleTopic1Message(payload);
        } else if ("your/topic2".equals(topic)) {
            handleTopic2Message(payload);
        }
    }

    private void handleTopic1Message(String payload) {
        // 处理来自 topic1 的消息
        System.out.println("处理 topic1 消息: " + payload);
    }

    private void handleTopic2Message(String payload) {
        // 处理来自 topic2 的消息
        System.out.println("处理 topic2 消息: " + payload);
    }
}

使用示例

在你的Spring Boot应用中,可以通过注入MqttUtil来发送消息:

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MqttController {

    @Autowired
    private MqttUtil mqttUtil;

    @GetMapping("/send")
    public String sendMessage() {
        mqttUtil.sendMessage("your/topic1", "Hello from Spring Boot");
        return "Message sent!";
    }
}

运行流程

  • 1.在 application.yml 文件中配置MQTT服务器的URL、用户名、密码、client_id、默认主题和订阅的主题
  • 2.启动MQTT Broker(如Mosquitto)
  • 3.确保硬件设备连接到MQTT Broker,并发布和订阅消息。
  • 4.启动Spring Boot应用程序,确保它可以发送接收MQTT消息。
  • 5.在控制台中查看接收到的消息,并根据不同的主题进行处理。

通过以上步骤,你可以在Spring Boot中配置和使用MQTT,并将其封装为工具类和事件监听机制,方便其他项目集成和使用。这种配置方式使得MQTT连接认证更加安全,代码更加灵活。

30岁终于买了一台不卡的电脑,可 坐在电脑前我的 却卡住了…

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