SpringBoot2.0集成MQTT功能之消息订阅处理

       距离上一篇【SpringBoot2.0集成MQTT消息推送功能】https://blog.csdn.net/qq_41018959/article/details/80592444博客已经过去有一段时间了，最近比较忙，也没时间整理【SpringBoot2.0集成MQTT消息之消息订阅处理】篇章，刚好早上闲下来，就趁这个机会整理一下。

       网上资料还是蛮多的，但也不是很全面，比如如何设置多个client，如何监听不同topic等，好了，废话不多说，还是跟上篇一样的环境，上代码：

        第一，pom配置，引入相关jar:

    org.springframework.integration
    spring-integration-stream


   org.springframework.integration
   spring-integration-mqtt
    

第二，配置MQTT服务器基本信息，在springBoot配置文件application.properties中配置，添加如下：

#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://192.168.2.133:61613
spring.mqtt.url=tcp://127.0.0.1:61613
#MQTT-连接服务器默认客户端ID
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=topic
#连接超时
spring.mqtt.completionTimeout=3000

第三，配置MQTT消息接收处理类：

/**
 * 〈一句话功能简述〉
 
 * 〈MQTT接收消息处理〉
 *
 * @author lenovo
 * @create 2018/6/4
 * @since 1.0.0
 */
@Configuration
@IntegrationComponentScan
public class MqttReceiveConfig {

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

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

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

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

    @Value("${spring.mqtt.default.topic}")
    private String defaultTopic;

    @Value("${spring.mqtt.completionTimeout}")
    private int completionTimeout ;   //连接超时


    @Bean
    public MqttConnectOptions getMqttConnectOptions(){
        MqttConnectOptions mqttConnectOptions=new MqttConnectOptions();
        mqttConnectOptions.setUserName(username);
        mqttConnectOptions.setPassword(password.toCharArray());
        mqttConnectOptions.setServerURIs(new String[]{hostUrl});
        mqttConnectOptions.setKeepAliveInterval(2);
        return mqttConnectOptions;
    }
    @Bean
    public MqttPahoClientFactory mqttClientFactory() {
        DefaultMqttPahoClientFactory factory = new DefaultMqttPahoClientFactory();
        factory.setConnectionOptions(getMqttConnectOptions());
        return factory;
    }

    //接收通道
    @Bean
    public MessageChannel mqttInputChannel() {
        return new DirectChannel();
    }

    //配置client,监听的topic 
    @Bean
    public MessageProducer inbound() {
        MqttPahoMessageDrivenChannelAdapter adapter =
                new MqttPahoMessageDrivenChannelAdapter(clientId+"_inbound", mqttClientFactory(),
                        "hello","hello1");
        adapter.setCompletionTimeout(completionTimeout);
        adapter.setConverter(new DefaultPahoMessageConverter());
        adapter.setQos(1);
        adapter.setOutputChannel(mqttInputChannel());
        return adapter;
    }

    //通过通道获取数据
    @Bean
    @ServiceActivator(inputChannel = "mqttInputChannel")
    public MessageHandler handler() {
        return new MessageHandler() {
            @Override
            public void handleMessage(Message message) throws MessagingException {
                String topic = message.getHeaders().get("mqtt_receivedTopic").toString();
                String type = topic.substring(topic.lastIndexOf("/")+1, topic.length());
                if("hello".equalsIgnoreCase(topic)){
                    System.out.println("hello,fuckXX,"+message.getPayload().toString());
                }else if("hello1".equalsIgnoreCase(topic)){
                    System.out.println("hello1,fuckXX,"+message.getPayload().toString());
                }
            }
        };
    }
}

第四，启动服务测试，使用postment调用上一篇的MQTT发送接口，分别往hello,hello1两个topic发送消息，测试接收情况：

        由此看出，可以正常监听topic并接收处理消息了。

        看到这里，朋友们可能有疑问，如果我要配置多个client，应该怎么处理呢？这个也简单，我们只要配置多个通道即可，简单代码如下：

//通道2
@Bean
public MessageChannel mqttInputChannelTwo() {
    return new DirectChannel();
}
//配置client2，监听的topic:hell2,hello3
@Bean
public MessageProducer inbound1() {
    MqttPahoMessageDrivenChannelAdapter adapter =
            new MqttPahoMessageDrivenChannelAdapter(clientId+"_inboundTwo", mqttClientFactory(),
                    "hello2","hello3");
    adapter.setCompletionTimeout(completionTimeout);
    adapter.setConverter(new DefaultPahoMessageConverter());
    adapter.setQos(1);
    adapter.setOutputChannel(mqttInputChannelTwo());
    return adapter;
}

//通过通道2获取数据
@Bean
@ServiceActivator(inputChannel = "mqttInputChannelTwo")
public MessageHandler handlerTwo() {
    return new MessageHandler() {
        @Override
        public void handleMessage(Message message) throws MessagingException {
            String topic = message.getHeaders().get("mqtt_receivedTopic").toString();
            String type = topic.substring(topic.lastIndexOf("/")+1, topic.length());
            if("hello2".equalsIgnoreCase(topic)){
                System.out.println("hello2 clientTwo,"+message.getPayload().toString());
            }else if("hello3".equalsIgnoreCase(topic)){
                System.out.println("hello3 clientTwo,"+message.getPayload().toString());
            }
        }
    };
}

        这样一来，我们就配置了两个client，client1监听处理hello、hello1主题消息，client2监听处理hello2、hello3主题，测试一下：

         从输出结果可以看出，我们发送不同的消息，分别由不同的client处理。所以，小伙伴，你理解了吗？

        【转载请注明出处——大道迷途】