一、 MQTT简介

MQTT是一种轻巧量级的、基于发布/订阅模式的传信协议，适用于材料受限的设备和矮小带宽阔、不可靠的网络周围。它广泛应用于物联网应用，如传感器传信、远程监控、消息通知等场景。

二、 Spring Boot整合MQTT

Spring Boot给了对MQTT协议的支持，使得开发者能轻巧松地将MQTT集成到Spring Boot应用程序中。

2.1 配置MQTT客户端

先说说需要在Spring Boot项目中添加依赖：

dependencies {
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.integration.annotation.MessagingGateway;
    import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;
    import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;
    import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;
    import org.springframework.messaging.MessageChannel;
    import org.springframework.messaging.handler.annotation.MessageMapping;
    import org.springframework.messaging.handler.annotation.SendTo;
    import org.springframework.stereotype.Controller;
   

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