阿里云物联网平台自定义Topic脚本解析功能演示

概述

之前物联网平台自定义Topic均做消息的直接透传，不做类似物模型模式的数据脚本解析。平台最新推出的自定义Topic脚本解析功能，设备通过携带解析标记（?_sn=default）的自定义Topic上报数据，物联网平台收到数据后，调用您在控制台提交的数据解析脚本，将自定义格式数据转换为JSON结构体，再流转给后续业务系统。本文主要演示该功能的具体功能实现。

Step By Step

1、创建产品和设备

2、添加脚本

示例脚本

3、设备端通过自定义Topic模拟上行数据

import com.alibaba.taro.AliyunIoTSignUtil; import com.google.common.util.concurrent.ThreadFactoryBuilder; import org.eclipse.paho.client.mqttv3.*; import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence; import java.util.HashMap; import java.util.Map; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.ScheduledThreadPoolExecutor; import java.util.concurrent.TimeUnit; // 透传类设备测试 public class IoTDemoPubSubDemoForPersonalTopic { // 设备三元组信息 public static String productKey = "a1wJG******"; public static String deviceName = "Device1"; public static String deviceSecret = "40YEyiGzXmvhDdpvbUVFCHjC********"; public static String regionId = "cn-shanghai"; private static String pubTopic = "/"+ productKey + "/" + deviceName + "/user/update?_sn=default";//自定义Topic做脚本解析 private static MqttClient mqttClient; public static void main(String [] args){ initAliyunIoTClient(); // 初始化Client ScheduledExecutorService scheduledThreadPool = new ScheduledThreadPoolExecutor(1, new ThreadFactoryBuilder().setNameFormat("thread-runner-%d").build()); scheduledThreadPool.scheduleAtFixedRate(()->postDeviceProperties(), 10,10, TimeUnit.SECONDS); } /** * 初始化 Client 对象 */ private static void initAliyunIoTClient() { try { // 构造连接需要的参数 String clientId = "java" + System.currentTimeMillis(); Map<String, String> params = new HashMap<>(16); params.put("productKey", productKey); params.put("deviceName", deviceName); params.put("clientId", clientId); String timestamp = String.valueOf(System.currentTimeMillis()); params.put("timestamp", timestamp); // cn-shanghai String targetServer = "tcp://" + productKey + ".iot-as-mqtt."+regionId+".aliyuncs.com:1883"; String mqttclientId = clientId + "|securemode=3,signmethod=hmacsha1,timestamp=" + timestamp + "|"; String mqttUsername = deviceName + "&" + productKey; String mqttPassword = AliyunIoTSignUtil.sign(params, deviceSecret, "hmacsha1"); connectMqtt(targetServer, mqttclientId, mqttUsername, mqttPassword); } catch (Exception e) { System.out.println("initAliyunIoTClient error " + e.getMessage()); } } public static void connectMqtt(String url, String clientId, String mqttUsername, String mqttPassword) throws Exception { MemoryPersistence persistence = new MemoryPersistence(); mqttClient = new MqttClient(url, clientId, persistence); MqttConnectOptions connOpts = new MqttConnectOptions(); // MQTT 3.1.1 connOpts.setMqttVersion(4); connOpts.setAutomaticReconnect(false); connOpts.setCleanSession(true); connOpts.setUserName(mqttUsername); connOpts.setPassword(mqttPassword.toCharArray()); connOpts.setKeepAliveInterval(60); mqttClient.connect(connOpts); } /** * 汇报属性 */ private static void postDeviceProperties() { try { //上报数据 System.out.println("自定义Topic上报属性值"); //0x000000000100320100000000 String hexString = "000000000100320100000000"; byte[] payLoad = hexToByteArray(hexString); MqttMessage message = new MqttMessage(payLoad); message.setQos(0); mqttClient.publish(pubTopic, message); } catch (Exception e) { System.out.println(e.getMessage()); } } /** * hex字符串转byte数组 * @param inHex 待转换的Hex字符串 * @return 转换后的byte数组结果 */ public static byte[] hexToByteArray(String inHex){ int hexlen = inHex.length(); byte[] result; if (hexlen % 2 == 1){ //奇数 hexlen++; result = new byte[(hexlen/2)]; inHex="0"+inHex; }else { //偶数 result = new byte[(hexlen/2)]; } int j=0; for (int i = 0; i < hexlen; i+=2){ result[j]=hexToByte(inHex.substring(i,i+2)); j++; } return result; } /** * Hex字符串转byte * @param inHex 待转换的Hex字符串 * @return 转换后的byte */ public static byte hexToByte(String inHex) { return (byte) Integer.parseInt(inHex, 16); } }

参考链接：LoRaWAN设备数据解析及开源MQTT SDK设备端模拟

4、上行消息查看

5、注意事项

1、在物联网平台创建自定义Topic时按正常Topic定义，不添加该解析标记； 2、仅解析设备上报云端的数据，不解析云端下行数据； 3、仅解析上报数据的Payload，并返回解析后的Payload； 4、解析前后，数据所在Topic不变。例如，设备发送到/${productKey}/${deviceName}/user/update的数据，解析后仍在该Topic中。

参考链接

自定义数据解析Topic概述

LoRaWAN设备数据解析及开源MQTT SDK设备端模拟