[Java知识库]springboot 整合 mqtt 实现消息发送

1、环境准备

1、本地已搭建MQTT服务 参考 windows环境搭建MQTT_音乐土豆-CSDN博客

2、新建Springboot项目

2、pom文件引入依赖

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

3、application.properties文件新增mqtt配置

server.port=8080
#MQTT配置信息
#MQTT-用户名
spring.mqtt.username=admin
#MQTT-密码
spring.mqtt.password=password
#MQTT-服务器连接地址，如果有多个，用逗号隔开，如：tcp://127.0.0.1:61613,tcp://127.0.0.1:61613
spring.mqtt.url=tcp://127.0.0.1:61613
#MQTT-连接服务器默认客户端ID 可自定义
spring.mqtt.client.id=mqttId
#MQTT-默认的消息推送主题，实际可在调用接口时指定
spring.mqtt.default.topic=test
#timeout 链接超时时间
mqtt.connection.timeout=20
#keep alive 单位为秒，MQTT 协议中约定：在 1.5*Keep Alive 的时间间隔内，如果 Broker 没有收到来自 Client 的任何数据包，那么 Broker 认为它和 Client 之间的连接已经断开；同样地, 如果 Client 没有收到来自 Broker 的任何数据包，那么 Client 认为它和 Broker 之间的连接已经断开
mqtt.keep.alive.interval=20

4、编写MqttClientUtil

@Component
@Slf4j
public class MqttClientUtil {
    @Value("${spring.mqtt.username}")
    private String username;
    @Value("${spring.mqtt.password}")
    private String password;
    @Value("${spring.mqtt.url}")
    private String host;
    @Value("${spring.mqtt.client.id}")
    private String clientId;
    @Value("${spring.mqtt.default.topic}")
    private String topic;
    @Value("${mqtt.connection.timeout}")
    private int timeOut;
    @Value("${mqtt.keep.alive.interval}")
    private int interval;

    private MqttClient mqttClient;
    private MqttConnectOptions mqttConnectOptions;

    @PostConstruct
    private void init(){
        connect(host, clientId);
    }

    /**
     * 链接mqtt
     * @param host
     * @param clientId
     */
    private void connect(String host,String clientId){
        try{
            mqttClient = new MqttClient(host,clientId,new MemoryPersistence());
            mqttConnectOptions = getMqttConnectOptions();
            mqttClient.connect(mqttConnectOptions);
        }catch (Exception e){
            log.error("mqtt服务链接异常!");
            e.printStackTrace();
        }
    }

    /**
     * 设置链接对象信息
     * setCleanSession  true 断开链接即清楚会话  false 保留链接信息 离线还会继续发消息
     * @return
     */
    private MqttConnectOptions getMqttConnectOptions(){
        MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
        mqttConnectOptions.setUserName(username);
        mqttConnectOptions.setPassword(password.toCharArray());
        mqttConnectOptions.setServerURIs(new String[]{host});
        mqttConnectOptions.setKeepAliveInterval(interval);
        mqttConnectOptions.setConnectionTimeout(timeOut);
        mqttConnectOptions.setCleanSession(true);
        return mqttConnectOptions;
    }

    /**
     *mqtt链接状态
     * @return
     */
    private boolean isConnect(){
        if(Objects.isNull(this.mqttClient)){
            return false;
        }
        return mqttClient.isConnected();
    }

    /**
     * 设置重连
     * @throws Exception
     */
    private void reConnect() throws Exception{
        if(Objects.nonNull(this.mqttClient)){
            log.info("mqtt 服务已重新链接...");
            this.mqttClient.connect(this.mqttConnectOptions);
        }
    }

    /**
     * 断开链接
     * @throws Exception
     */
    private void closeConnect() throws Exception{
        if(Objects.nonNull(this.mqttClient)){
            log.info("mqtt 服务已断开链接...");
            this.mqttClient.disconnect();
        }
    }

    /**
     * 发布消息
     * @param topic
     * @param message
     * @param qos
     * @throws Exception
     */
    public void sendMessage(String topic,String message,int qos) throws Exception {
        if(Objects.nonNull(this.mqttClient) && this.mqttClient.isConnected()){
            MqttMessage mqttMessage = new MqttMessage();
            mqttMessage.setPayload(message.getBytes());
            mqttMessage.setQos(qos);

            MqttTopic mqttTopic = mqttClient.getTopic(topic);

            if(Objects.nonNull(mqttTopic)){
                try{
                    MqttDeliveryToken publish = mqttTopic.publish(mqttMessage);
                    if(publish.isComplete()){
                        log.info("消息发送成功---->{}",message);
                    }
                }catch(Exception e){
                    log.error("消息发送异常",e);
                }
            }
        }else{
            reConnect();
        }
    }
}

5、编写controller

@Slf4j
@RestController
public class TestController {
    @Autowired
    private MqttClientUtil mqttClientUtil;

	@RequestMapping("/send")
    public String sendMessage(){
        String topic = "test";
        String message = "测试 mqtt 消息发布";
        //0:最多一次 1：最少一次 2：至少一次
        int qos = 2;
        try{
            mqttClientUtil.sendMessage(topic,message,qos);
        }catch(Exception e){
            log.error("mqtt 消息发送异常",e);
        }
        return "mqtt 消息已发送！";
    }
}

6、测试

http://localhost:8080/send

也可以打开Mqtt box 订阅topic为test

可以看到，消息已经成功发出！