mqtt集成springboot设置重连机制

在Spring Boot中集成MQTT并设置重连机制，可以通过配置MqttPahoClientFactory来实现。下面是一个简单的示例代码：

1. 在application.properties或application.yml中添加MQTT连接配置：

spring.mqtt.url=tcp://localhost:1883
spring.mqtt.username=username
spring.mqtt.password=password

2. 创建一个MqttPahoClientFactory bean，用于创建MqttClient实例，并设置重连机制：

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.mqtt.core.DefaultMqttPahoClientFactory;

@Configuration
public class MqttConfig {

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

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

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

    @Bean
    public DefaultMqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        MqttConnectOptions options = new MqttConnectOptions();
        options.setAutomaticReconnect(true); // 开启自动重连
        options.setCleanSession(false); // 设置为false，以便在断开连接后可以保留会话状态
        options.setUserName(mqttUsername);
        options.setPassword(mqttPassword.toCharArray());
        factory.setConnectionOptions(options);
        return factory;
    }
}

3. 在需要使用MQTT的地方注入MqttPahoClientFactory bean，例如在MessageDrivenChannelAdapter中使用：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.integration.annotation.MessageEndpoint;
import org.springframework.integration.annotation.ServiceActivator;
import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
import org.springframework.messaging.MessageHandler;

@MessageEndpoint
public class MqttMessageEndpoint {

    private final MqttPahoClientFactory mqttClientFactory;

    @Autowired
    public MqttMessageEndpoint(MqttPahoClientFactory mqttClientFactory) {
        this.mqttClientFactory = mqttClientFactory;
    }

    @ServiceActivator(inputChannel = "mqttInputChannel")
    public MessageHandler mqttMessageHandler() {
        MqttPahoMessageDrivenChannelAdapter adapter = new MqttPahoMessageDrivenChannelAdapter(
                "clientId", mqttClientFactory, "topic");
        adapter.setCompletionTimeout(5000);
        adapter.setConverter(new DefaultPahoMessageConverter());
        adapter.setQos(1);
        return adapter;
    }
}

在上面的示例中，将MqttConnectOptions的`setAutomaticReconnect`方法设置为true，以开启自动重连功能。此外，将MqttConnectOptions的`setCleanSession`方法设置为false，以便在断开连接后可以保留会话状态。

请根据你的实际需求进行适当的调整和配置。希望这对你有所帮助！