前言

近期為了準備畢設，準備使用SpringBoot搭建mqtt后端，本篇主要記錄了在IDEA中搭建SpringBoot mqtt的多模塊項目的過程

開發工具及系統環境 IDE：IntelliJ IDEA 2020.2 操作系統：Windows 10 2004 Java Version：1.8 SpringBoot Version：2.1.17.RELEASE項目路徑

Study |----study-common# 存放公共類 |----study-mapper# mapper層 |----study-mqtt # mqtt相關配置文件及接口 |----study-service # service層 |----study-serviceimpl # service的實現類 |----study-web # web層 |----pom.xml配置過程1. 搭建父項目

在IDEA中新建一個SpringBoot工程

這里我使用了阿里云的啟動服務，正常使用可以直接用原本的啟動服務

根據你的需求選擇Java版本，初始化類型并配置groupID和artifactId，我這里配置成我的域名的反寫，并將artifactId定義成Study。配置完成后單擊Next

這一步選擇你需求的SpringBoot版本，我這里選擇的是2.1.17.RELEASE，然后單擊NEXT。在這一步中不需要勾選任何依賴。

選擇保存的路徑，點擊Finish完成創建。

刪除不需要的文件。將目錄下的src/,HELP.md,mvnw,mvnw.cmd等文件全部刪除（不包括.gitigore）

至此，父項目一級已經創建完成，最后項目目錄如下：

2. 搭建子項目

右鍵項目根目錄->新建->新模塊

選擇Maven，單擊Next

配置父項，項目名稱以及構建坐標，完成后單擊Finish。這里以study-common模塊為例

以此類推創建整個項目，項目目錄如圖所示

至此，我們搭建完所有的子項目，接下來開始配置各個項目的pom文件

3. 配置各個模塊

1. 配置父項目

配置父項目的pom.xml文件

父項目的pom.xml主要是對子項目的引用起到一個約束作用，固在父項目的pom.xml需要使用dependencyManagement這一項來約束子項目中各個依賴的版本。在父項目中可以引用子項目都用得到的引用。父項目的pom.xml文件如下：

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu</groupId> <artifactId>study</artifactId> <packaging>pom</packaging> <version>1.0.0</version> <modules><module>study-common</module><module>study-service</module><module>study-serviceimpl</module><module>study-web</module><module>study-mapper</module><module>study-mqtt</module> </modules> <name>study</name> <description>Demo project for Spring Boot</description> <parent><artifactId>spring-boot-starter-parent</artifactId><groupId>org.springframework.boot</groupId><version>2.1.17.RELEASE</version><relativePath/> </parent> <properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.1.17.RELEASE</spring-boot.version><mybatis.boot.starter.version>2.1.4</mybatis.boot.starter.version><mysql.connector.java.version>8.0.22</mysql.connector.java.version><druid.version>1.2.0</druid.version><integration.version>2.3.7.RELEASE</integration.version><stream.integration.version>5.4.2</stream.integration.version><mqtt.integration.version>5.4.2</mqtt.integration.version> </properties> <dependencies><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-thymeleaf</artifactId></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope></dependency> </dependencies> <dependencyManagement><dependencies> <dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>${spring-boot.version}</version><type>pom</type><scope>import</scope> </dependency> <dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>${mybatis.boot.starter.version}</version> </dependency> <dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>${mysql.connector.java.version}</version> </dependency> <dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>${druid.version}</version> </dependency></dependencies> </dependencyManagement> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><version>2.1.17.RELEASE</version> </plugin></plugins> </build></project>

2. 配置common模塊

配置pom.xml文件

common模塊主要包括一些通用的類和接口，固這里只需要配置下parent這一項指向父項目即可，common模塊的pom.xml配置文件如下：

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version> </parent> <groupId>com.itbu.study</groupId> <artifactId>common</artifactId> <version>1.0.0</version> <modelVersion>4.0.0</modelVersion> <packaging>jar</packaging> <properties><java.version>1.8</java.version> </properties> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

創建所需要的類和接口

配置完pom.xml后，就可以在目錄下創建所需要的類以及接口。在本項目中我分別創建了作為pojo類的UserBean和作為json返回結果的JsonResult類作為通用類，項目結構如下：

study-common|----pom.xml|----src|----test|----main|----resources|----java|----com.itbu.study.common|----bean|----UserBean.java|----result|----JsonResult.java

UserBean.java文件

package com.itbu.study.common.bean;public class UserBean { private int id; private String username; private String password; public int getId() {return id; } public String getPassword() {return password; } public String getUsername() {return username; } public void setPassword(String password) {this.password = password; } public void setId(int id) {this.id = id; } public void setUsername(String username) {this.username = username; } public UserBean(){ } public UserBean(String username, String password){this.username = username;this.password = password; }}

JsonResult.java文件

package com.itbu.study.common.result;public class JsonResult<T> { private int code; private String msg; private T data; public JsonResult(int Code,String msg){this.code = Code;this.msg = msg; } public JsonResult(T data) {this.data = data;this.code = 0;this.msg = '操作成功！'; } public JsonResult(T data, String msg) {this.data = data;this.code = 0;this.msg = msg; } public String getMsg() {return msg; } public int getCode() {return code; } public T getData() {return data; } public void setData(T data) {this.data = data; } public void setMsg(String msg) {this.msg = msg; } public void setCode(int code) {this.code = code; }}

3. 配置mapper模塊

mapper模塊對應的是mapper層，也就是我們常說的DAO層，用于與數據庫進行通信，讀寫操作。這里我們用的持久層框架是Mybatis，連接的數據庫是mysql數據庫。同時需要common模塊中的各個pojo類，這里需要引入各個引用。操作步驟如下：

配置pom.xml文件

這里我們需要引入mybatis，druid和mysql支持，固配置文件編寫如下：

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu.study</groupId> <artifactId>mapper</artifactId> <version>1.0.0</version> <name>mapper</name> <description>Demo project for Spring Boot</description> <packaging>jar</packaging> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version><relativePath>../pom.xml</relativePath> </parent> <properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.1.17.RELEASE</spring-boot.version> </properties> <dependencies><!-- 內部引用 --><dependency> <groupId>com.itbu.study</groupId> <artifactId>common</artifactId> <version>1.0.0</version></dependency><!-- 外部引用 --><dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId></dependency><dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId></dependency><dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId></dependency> </dependencies> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

編寫接口和映射文件

和不分模塊的操作一樣，在resource文件夾下創建mapper目錄，并編寫用于映射的xml文件。同時創建對應的接口，本項目工程目錄大致如下：

study-mapper|----pom.xml|----src|----test|----main|----java|----com.itbu.study.mapper|----UserMapper.java|----resources|----mapper|----UserMapper.xml

UserMapper.java文件

package com.itbu.study.mapper;import com.itbu.study.common.bean.UserBean;import java.util.List;public interface UserMapper { List<UserBean> getAll();}

UserMapper.xml

<?xml version='1.0' encoding='UTF-8' ?><!DOCTYPE mapper PUBLIC '-//mybatis.org//DTD Mapper 3.0//EN' 'http://mybatis.org/dtd/mybatis-3-mapper.dtd' ><mapper namespace='com.itbu.study.mapper.UserMapper'> <select resultType='com.itbu.study.common.bean.UserBean'>select * from mqtt.user_table </select></mapper>

4. 配置service模塊

service模塊也就是service層，主要是一些服務接口方便給controller層調用。步驟如下:

配置pom.xml文件

service層需要用到common模塊中的pojo類，這里需要對該模塊添加依賴項

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version><relativePath>../pom.xml</relativePath> </parent> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu.study</groupId> <artifactId>service</artifactId> <version>1.0.0</version> <packaging>jar</packaging> <name>service</name> <properties><java.version>1.8</java.version> </properties> <dependencies><dependency> <groupId>com.itbu.study</groupId> <artifactId>common</artifactId> <version>1.0.0</version></dependency> </dependencies> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

編寫service各個接口

這里接口與mapper層類似，就不一一贅述，這里直接放代碼

UserService.java

package com.itbu.study.service;import com.itbu.study.common.bean.UserBean;import java.util.List;public interface UserService { List<UserBean> getAll();}

5. 配置serviceimpl模塊

serviceimpl即service接口的各個實現類，實現步驟如下：

配置pom.xml文件

serviceimpl需要mapper層的支持，需要實現service層的各個接口，也需要引用到common模塊中的pojo類，我們直接加上這三項的依賴

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu.study</groupId> <artifactId>serviceimpl</artifactId> <version>1.0.0</version> <name>serviceimpl</name> <description>Demo project for Spring Boot</description> <packaging>jar</packaging> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version> </parent> <properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.1.17.RELEASE</spring-boot.version> </properties> <dependencies><dependency> <groupId>com.itbu.study</groupId> <artifactId>common</artifactId> <version>1.0.0</version></dependency><dependency> <groupId>com.itbu.study</groupId> <artifactId>service</artifactId> <version>1.0.0</version></dependency><dependency> <groupId>com.itbu.study</groupId> <artifactId>mapper</artifactId> <version>1.0.0</version></dependency> </dependencies> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

根據service各個接口編寫實現類

UserServiceimpl.java 注意在實現類上要加上@Service標注以用于SpringBoot框架識別

package com.itbu.study.serviceimpl;import com.itbu.study.common.bean.UserBean;import com.itbu.study.mapper.UserMapper;import com.itbu.study.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserServiceImpl implements UserService { @Autowired private UserMapper userMapper; @Override public List<UserBean> getAll() {return userMapper.getAll(); }}

6. 配置web模塊

接下來就到了核心部分，也就是與不分模塊配置差異較大的部分。Web層需要配置啟動類以及配置文件，內容較多，配置步驟如下：

配置pom.xml文件

Web層將直接引用Service層的各個接口，Common模塊的各個類，這里我們直接加上依賴

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd'> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu.study</groupId> <artifactId>serviceimpl</artifactId> <version>1.0.0</version> <name>serviceimpl</name> <description>Demo project for Spring Boot</description> <packaging>jar</packaging> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version> </parent> <properties><java.version>1.8</java.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><spring-boot.version>2.1.17.RELEASE</spring-boot.version> </properties> <dependencies><dependency> <groupId>com.itbu.study</groupId> <artifactId>common</artifactId> <version>1.0.0</version></dependency><dependency> <groupId>com.itbu.study</groupId> <artifactId>service</artifactId> <version>1.0.0</version></dependency><dependency> <groupId>com.itbu.study</groupId> <artifactId>mapper</artifactId> <version>1.0.0</version></dependency> </dependencies> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

編寫各個Controller以及配置文件

先根據以下的項目結構創建對應的文件，項目結構如下：

study-web|----pom.xml|----src|----test|----java|----com.itbu.study.web|----WebApplicationTests.java #測試類|----main|----java|----com.itbu.study.web|----WebApplication.java|----controller|----ApiController.java |----resources |----config |----application.yml |----application-dev.yml

編寫啟動類，記得加上MapperScan

WebApplication.java

package com.itbu.study.web;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication(scanBasePackages = {'com.itbu.study.*'})@MapperScan('com.itbu.study.mapper')public class WebApplication { public static void main(String[] args) {SpringApplication.run(WebApplication.class, args); }}

編寫Controller層

ApiController.java

package com.itbu.study.web.controller;import com.itbu.study.common.bean.UserBean;import com.itbu.study.common.result.JsonResult;import com.itbu.study.service.UserService;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;import javax.xml.ws.RequestWrapper;import java.util.List;@RestController@RequestMapping('/api')public class ApiController { private final Logger logger = LoggerFactory.getLogger(this.getClass()); public ApiController(UserService userService){this.userService = userService; } private final UserService userService; @RequestMapping('/index') public List<UserBean> index(){return userService.getAll(); }}

在配置文件中設置數據源和mapper映射文件以及監聽端口

application-dev.xml

server: port: 10000mybatis: mapper-locations: classpath*:mapper/*.xml #注意此處與未分模塊的區別spring: datasource: username: root password: 123456 url: jdbc:mysql://192.168.28.88:10090/mqtt?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC driver-class-name: com.mysql.cj.jdbc.Driver

7. 測試

至此，我們以及配置完了一個多模塊的MQTT后端基本項目，接下來進行簡單測試

運行項目并在瀏覽器中輸入http://localhost:10000/api/index, 返回以下結果表明測試成功

4. 配置MQTT模塊

前面我們完成了SpringBoot基礎項目的配置，接下來我們將mqtt也做成模塊，步驟如下：

配置pom.xml文件

我們集成mqtt功能主要使用了spring-integration-mqtt這個jar包，所以我們在pom中添加對這個包的依賴，pom.xml文件如下：

<?xml version='1.0' encoding='UTF-8'?><project xmlns='http://maven.apache.org/POM/4.0.0' xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:schemaLocation='http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd'> <parent><artifactId>study</artifactId><groupId>com.itbu</groupId><version>1.0.0</version> </parent> <modelVersion>4.0.0</modelVersion> <groupId>com.itbu.study</groupId> <artifactId>mqtt</artifactId> <packaging>jar</packaging> <properties><java.version>1.8</java.version> </properties> <dependencies><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> </dependencies> <build><plugins> <plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId> </plugin></plugins> </build></project>

在study-web的配置文件中添加如下配置：

mqtt: enabled: true username: root password: 123456 url: tcp://192.168.28.88:15005 producer: clientId: server defaultTopic: default consumer: clientId: client defaultTopic: default

編寫MQTT各個配置類以及方法

項目結構如下：

study-mqtt|----pom.xml|----src|----test|----main|----resources|----java|----com.itbu.study.mqtt|----MqttBaseConfig.java|----MqttInConfig.java|----MqttOutConfig.java|----MqttMessageReceiver.java|----MqttMessageSender.java

MqttBaseConfig.java

package com.itbu.study.mqtt;import org.eclipse.paho.client.mqttv3.MqttConnectOptions;import org.springframework.beans.factory.annotation.Value;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.integration.mqtt.core.DefaultMqttPahoClientFactory;import org.springframework.integration.mqtt.core.MqttPahoClientFactory;@Configuration@ConditionalOnProperty(value = 'mqtt.enabled', havingValue = 'true')public class MqttBaseConfig { @Value('${mqtt.url:#{null}}') private String[] url; @Value('${mqtt.username:}') private String username; @Value('${mqtt.password:}') private String password; @Bean public MqttPahoClientFactory factory(){DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();MqttConnectOptions options = new MqttConnectOptions();if(username != null) options.setUserName(username);if(password != null) options.setPassword(password.toCharArray());options.setServerURIs(url);factory.setConnectionOptions(options);return factory; }}

MqttInConfig.java

package com.itbu.study.mqtt;import com.itbu.study.mqtt.MqttMessageReceiver;import org.springframework.beans.factory.annotation.Value;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;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.MqttPahoClientFactory;import org.springframework.integration.mqtt.inbound.MqttPahoMessageDrivenChannelAdapter;import org.springframework.integration.mqtt.support.DefaultPahoMessageConverter;import org.springframework.messaging.MessageChannel;import org.springframework.messaging.MessageHandler;@Configuration@ConditionalOnProperty(value = 'mqtt.enabled', havingValue = 'true')public class MqttInConfig { private final MqttMessageReceiver mqttMessageReceiver; public MqttInConfig(MqttMessageReceiver mqttMessageReceiver){this.mqttMessageReceiver = mqttMessageReceiver; } @Value('${mqtt.producer.clientId:') private String clientId; @Value('${mqtt.producer.defaultTopic}') private String topic; @Bean public MessageChannel mqttInputChannel(){return new DirectChannel(); } @Bean public MessageProducer channelInbound(MessageChannel mqttInputChannel, MqttPahoClientFactory factory){MqttPahoMessageDrivenChannelAdapter adapter = new MqttPahoMessageDrivenChannelAdapter(clientId, factory, topic);adapter.setCompletionTimeout(5000);adapter.setConverter(new DefaultPahoMessageConverter());adapter.setQos(2);adapter.setOutputChannel(mqttInputChannel);return adapter; } @Bean @ServiceActivator(inputChannel = 'mqttInputChannel') public MessageHandler mqttMessageHandler(){return this.mqttMessageReceiver; }}

MqttOutConfig.java

package com.itbu.study.mqtt;import org.springframework.beans.factory.annotation.Value;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;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.mqtt.core.MqttPahoClientFactory;import org.springframework.integration.mqtt.outbound.MqttPahoMessageHandler;import org.springframework.messaging.MessageChannel;import org.springframework.messaging.MessageHandler;@Configuration@ConditionalOnProperty(value = 'mqtt.enabled', havingValue = 'true')public class MqttOutConfig { @Value('${mqtt.consumer.clientId:}') private String clientId; @Value('${mqtt.consumer.defaultTopic}') private String topic; @Bean public MessageChannel mqttOutputChannel(){return new DirectChannel(); } @Bean @ServiceActivator(inputChannel = 'mqttOutputChannel') public MessageHandler mqttOutBound(MqttPahoClientFactory factory){MqttPahoMessageHandler messageHandler = new MqttPahoMessageHandler(clientId, factory);messageHandler.setAsync(true);messageHandler.setDefaultQos(2);messageHandler.setDefaultTopic(topic);return messageHandler; }}

MqttMessageReceiver.java

package com.itbu.study.mqtt;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;import org.springframework.context.annotation.ComponentScan;import org.springframework.integration.mqtt.support.MqttHeaders;import org.springframework.messaging.Message;import org.springframework.messaging.MessageHandler;import org.springframework.messaging.MessagingException;import org.springframework.stereotype.Component;@Component@ConditionalOnProperty(value = 'mqtt.enabled',havingValue = 'true')public class MqttMessageReceiver implements MessageHandler { private final Logger logger = LoggerFactory.getLogger(this.getClass()); @Override public void handleMessage(Message<?> message) throws MessagingException {String topic = String.valueOf(message.getHeaders().get(MqttHeaders.RECEIVED_TOPIC));String payload = String.valueOf(message.getPayload());logger.info('接收到 mqtt消息， 主題：{} 消息:{}', topic, payload); }}

MqttMessageSender.java

package com.itbu.study.mqtt;import org.springframework.integration.annotation.MessagingGateway;import org.springframework.integration.mqtt.support.MqttHeaders;import org.springframework.messaging.handler.annotation.Header;import org.springframework.stereotype.Component;@MessagingGateway(defaultRequestChannel = 'mqttOutputChannel')@Componentpublic interface MqttMessageSender { void sendToMqtt(String data); void sendToMqtt(@Header(MqttHeaders.TOPIC) String topic, String payload); void sendToMqtt(@Header(MqttHeaders.TOPIC) String topic, @Header(MqttHeaders.QOS) int qos, String payload);}

在啟動類中添加@IntegrationComponentScan注解

package com.itbu.study.web;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.integration.annotation.IntegrationComponentScan;@SpringBootApplication(scanBasePackages = {'com.itbu.study.*','com.itbu.study.mqtt'})@MapperScan('com.itbu.study.mapper')@IntegrationComponentScan(basePackages = 'com.itbu.study.mqtt') //這里添加，不然無法自動注入public class WebApplication { public static void main(String[] args) {SpringApplication.run(WebApplication.class, args); }}

編寫對應Controller，我這里直接在ApiController上修改了

package com.itbu.study.web.controller;import com.itbu.study.common.bean.UserBean;import com.itbu.study.common.result.JsonResult;import com.itbu.study.mqtt.MqttMessageSender;import com.itbu.study.service.UserService;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;import javax.xml.ws.RequestWrapper;import java.util.List;@RestController@RequestMapping('/api')public class ApiController { private final Logger logger = LoggerFactory.getLogger(this.getClass()); private final MqttMessageSender mqttMessageSender; public ApiController(MqttMessageSender mqttMessageSender, UserService userService){this.mqttMessageSender = mqttMessageSender;this.userService = userService; } private final UserService userService; @RequestMapping('/index') public List<UserBean> index(){return userService.getAll(); } @RequestMapping('/mqtt') public JsonResult<?> mqtt_sender(@RequestParam('msg')String msg){logger.info('Send mqtt msg: {}', msg);mqttMessageSender.sendToMqtt(msg);logger.info('Send successfully!');return new JsonResult<>(0,'Send Successfully'); }}

測試

首先我們運行后端項目，可以看到日志打出以下輸出，說明后端項目正常啟動

然后我們使用mqtt.fx這個軟件往訂閱主題default發送helloworld

發現日志打印如下信息，表面輸入通道正常：

然后我們在瀏覽器中輸入http://localhost:10000/api/mqtt?msg=1234556 并按下回車，瀏覽器顯示如下：

可以看到日志中打印了如下內容：

因為我們訂閱的主題也是default，所以也收到了生產者發送的信息，我們打開mqtt.fx, 訂閱default主題，可以收到如下信息：

測試成功

最后放上工程的源碼：GitHub

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