SpringBoot2.x集成MQTT实现消息订阅

1.引入相关的依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-integration</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-stream</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-mqtt</artifactId>
</dependency>

2. 在配置文件下配置MQTT服务器信息

spring.mqtt.username = username
spring.mqtt.password = password
spring.mqtt.url = tcp://xx.xx.xx.xx:18083 
spring.mqtt.client.id = clientid
spring.mqtt.default.topic = topic 
spring.mqtt.default.completionTimeout = 3000

3.配置MQTT消息推送配置

/**
 * MQTT配置
 * @Author: songyaru
 * @Date: 2020/9/01 10:04
 * @Version 1.0
 */

@Slf4j
@Configuration
@IntegrationComponentScan
public class MqttReceiveConfig {

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

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

    @Value("${spring.mqtt.url}")
    private String hostUrl;

    @Value("${spring.mqtt.client.id}")
    private String clientId;

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

    @Value("${spring.mqtt.default.completionTimeout}")
    private int completionTimeout;//连接超时

    //初始化连接
    @Bean
    public MqttConnectOptions getMqttConnectOptions() {
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName(username);
        mqttConnectOptions.setPassword(password.toCharArray());
        mqttConnectOptions.setServerURIs(new String[]{hostUrl});
        mqttConnectOptions.setKeepAliveInterval(50);
        return mqttConnectOptions;
    }

    //初始化mqtt工厂
    @Bean
    public MqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        factory.setConnectionOptions(getMqttConnectOptions());
        return factory;
    }

    //接收通道
    @Primary
    @Bean("mqttInputChannel")
    public MessageChannel mqttInputChannel() {
        return new DirectChannel();
    }

    //配置client,监听的topic
    @Bean
    public MessageProducer inbound(@Qualifier("mqttInputChannel") MessageChannel messageChannel) {
        MqttPahoMessageDrivenChannelAdapter adapter =
                new MqttPahoMessageDrivenChannelAdapter(clientId + "_inbound", mqttClientFactory(),defaultTopic); //这里的defaultTopic是发布者的主题               
        adapter.setCompletionTimeout(completionTimeout);
        adapter.setConverter(new DefaultPahoMessageConverter());
        adapter.setQos(1);
        adapter.setOutputChannel(messageChannel);
        return adapter;
    }


   //订阅消费数据,通过通道获取数据
    @Bean
    @ServiceActivator(inputChannel = "mqttInputChannel")
    public MessageHandler handler() {
        return new MessageHandler() {
            @Override
            public void handleMessage(Message<?> message) throws MessagingException {
                log.info("主题：{}，消息接收到的数据：{}", message.getHeaders().get("mqtt_receivedTopic"), message.getPayload());
            }
        };
    }

}

4.启动服务，使用上一篇博文的消息接口发送消息。