STMSpring Boot、MQTT和React Native：智能停车管理系统的全栈开发详解（附代码示例）

由于篇幅所限，以下仅展示核心函数和部分核心代码。

// MQTT消息订阅服务
@Service
public class MqttSubscriptionService {
    private static final Logger LOGGER = LoggerFactory.com.example.demo.controller.getLogger(MqttSubscriptionService.class);
 
    @Autowired
    private MqttPushClient mqttPushClient;
 
    public void subscribeTopic(String topicName, MqttMessageListener listener) {
        try {
            mqttPushClient.subscribeTopic(topicName, listener);
            LOGGER.info("Subscribed to topic: " + topicName);
        } catch (MqttException e) {
            LOGGER.error("Subscription to topic " + topicName + " failed", e);
        }
    }
}
 
// MQTT推送客户端
@Component
public class MqttPushClient {
    private static final Logger LOGGER = LoggerFactory.getLogger(MqttPushClient.class);
 
    private MqttClient mqttClient;
 
    public void subscribeTopic(String topicName, MqttMessageListener listener) throws MqttException {
        IMqttMessageListener topicListener = new MqttMessageListener() {
            @Override
            public void messageArrived(String topic, MqttMessage message) throws Exception {
                listener.messageArrived(topic, message);
            }
        };
 
        mqttClient.subscribe(topicName, topicListener);
    }
 
    // 省略其他方法，如建立连接、发布消息等
}
 
// 前端React Native代码片段
export default class HomeScreen extends Component {
  componentDidMount() {
    // 订阅MQTT主题
    this.props.mqttSubscriptionService.subscribeTopic('smart_parking/telemetry', this.handleIncomingMessage);
  }
 
  handleIncomingMessage = (topic, message) => {
    // 处理接收到的消息
    console.log('Received message on topic: ', topic, ' - Message: ', message.toString());
  };
 
  render() {
    return (
      <View style={styles.container}>
        {/* 渲染UI组件 */}
      </View>
    );
  }
}
 
const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  // 其他样式定义
});

以上代码展示了如何在智能停车管理系统中使用MQTT协议进行消息订阅和处理。代码中包含了服务层、推送客户端和前端React Native组件的简化示例，展示了如何在实际应用中集成MQTT通信。