如何通过配置文件实现springboot结合mqtt

可以通过以下步骤实现springboot结合mqtt：

1. 在pom.xml文件中添加mqtt依赖。如下：

<dependency>
    <groupId>org.springframework.integration</groupId>
    <artifactId>spring-integration-mqtt</artifactId>
    <version>5.3.7.RELEASE</version>
</dependency>

2. 创建mqtt配置文件application.yml，配置mqtt相关信息。如下：

mqtt:
  url: tcp://localhost:1883
  username: admin
  password: admin
  clientId: springboot-mqtt

3. 创建SpringBoot配置类MqttConfig，读取mqtt配置信息并创建mqtt连接。如下：

@Configuration
public class MqttConfig {

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

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

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

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

    @Bean
    public DefaultMqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        MqttConnectOptions options = new MqttConnectOptions();
        options.setUserName(username);
        options.setPassword(password.toCharArray());
        factory.setConnectionOptions(options);
        return factory;
    }

    @Bean
    public IntegrationFlow mqttInFlow() {
        return IntegrationFlows.from(
                Mqtt.messageDrivenChannelAdapter(
                        MqttPahoMessageDrivenChannelAdapter(url, clientId, mqttClientFactory()))
                        .topics("topic"))
                .handle(messageHandler())
                .get();
    }

    @Bean
    public MessageHandler messageHandler() {
        return message -> {
            System.out.println("Received message: " + message.getPayload());
        };
    }
}

4. 创建一个main方法来启动SpringBoot项目。如下：

@SpringBootApplication
public class MqttApplication {

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

以上就是通过配置文件实现springboot结合mqtt的步骤。