【BW16】AT指令体验之MQTT

#### 我用emqx在本地搭建了一个MQTT服务器，搭建过程可以查看官网搭建方式 # 01 连接Wifi 连接WiFi请看上篇帖子 # 02 配置MQTT 命令： `AT+MQTT=<key>,<data>` 参数2：`<data>`设置的参数 参数1：`<key>`MQTT参数。 1：设置连接的域名或 IP 2：设置服务器端口号 3：设置连接方式(暂时默认 1：使用tcp连接) 4：设置客户端ID 5：设置用户名(最大长度63字节) 6：设置登录密码(最大长度63字节) 7：设置遗嘱消息 格式为 ```c AT+MQTT=7,<LWT_topic>,<LWT_qos>,<LWT_Retained>,<LWTpayload> LWT_topic：遗嘱主题(不需要遗嘱这里设置为空) LWT_qos：遗嘱 QOS(0/1/2) LWT_Retained：遗嘱 retained(0/1) LWTpayload：遗嘱消息内容 ``` # 示例 ```c AT+MQTT=1,192.168.1.9 // 设置MQTT服务器URL [AI_HalWriteFlash()-328]flash save ok [AI_FAtMqtt()-183]AI_HalWriteFlash success OK [MEM] After do cmd, available heap 120224 AT+MQTT=2,1883 // 设置MQTT服务器端口 [AI_HalWriteFlash()-328]flash save ok [AI_FAtMqtt()-183]AI_HalWriteFlash success OK [MEM] After do cmd, available heap 120224 AT+MQTT=3,1 // 设置连接方式 TCP [AI_FAtMqtt()-204]don't need save flash OK [MEM] After do cmd, available heap 120224 AT+MQTT=4,bw16 // 设置客户端ID [AI_HalWriteFlash()-328]flash save ok [AI_FAtMqtt()-183]AI_HalWriteFlash success OK [MEM] After do cmd, available heap 120224 AT+MQTT=5, // 设置用户名 我这里为空 [AI_FAtMqtt()-77]cmd format error +MQTT:3 ERROR [MEM] After do cmd, available heap 120224 AT+MQTT=6, // 设置密码 我这里为空 [AI_FAtMqtt()-77]cmd format error +MQTT:3 ERROR [MEM] After do cmd, available heap 120224 AT+MQTT? // 查询 MQTT 连接和配置情况 +MQTT:0,192.168.1.9,1883,1,bw16,,,,0,0, OK [MEM] After do cmd, available heap 120224 AT+MQTT // 连接MQTT [AI_MqttPrvMQTTTask()-2351]not set LWT [AI_MqttPrvMQTTTask()-2357]MQTT connect config host:192.168.1.9:1883 username: password: clientID:bw16 use tcp OK [MEM] After do cmd, available heap 103680 [AI_MqttDataHandle()-1507]start MQTT connect host:192.168.1.9:1883 username: password: clientID:bw16 willFlag:0 use tcp [AI_MqttNetworkConnect()-532]addr=192.168.1.9 [AI_MqttSetStatus()-1487]Set mqtt status to MQTT_CONNECT [AI_MqttDataHandle()-1544]send mqtt connect cmd success [AI_MqttDataHandle()-1555]Read packet type is CONNACK [AI_MqttDataHandle()-1576]recive MQTT Connected ack // 连接成功 ``` #### 此时，后台会有对应客户端连接  # 03 订阅消息 命令： `AT+MQTTSUB=<topic>,<qos>` 参数1：`<topic>`要订阅的主题。(最多订阅四个主题) 参数2：`<qos>`qos 等级(0,1,2)。 ```c AT+MQTTSUB=topic,0 [AI_MqttSetStatus()-1487]Set mqtt status to MQTT_SUBTOPIC [AI_MqttAppSubscribeTopic()-2225]send topic topic cmd success,wait ack [AI_MqttDataHandle()-1555]Read packet type is SUBACK [AI_MqttDataHandle()-1625]wait subscribe ack success,grantedQoS=0 [AI_MqttSetStatus()-1487]Set mqtt status to MQTT_RUNNING [AI_MqttAppSubscribeTopic()-2240]recive Subscribe ack,subscribe success OK [MEM] After do cmd, available heap 103136 ``` 后台显示  #### 当订阅消息后，该主题有消息后，就会通过串口显示 #### 其他客户端发送消息  #### BW16收到主题 ```c [AI_MqttMessageArrived()-2140]Message arrived +EVENT:MQTT_SUB,topic,18,{ "msg": "hello" } ``` # 04 发布消息 命令： `AT+MQTTPUB=<topic>,<qos>,<Retained>,<payload>` 参数1：`<topic>`要发布的主题 参数2：`<qos>`qos 等级(0,1,2)。 参数3：`<Retained>`0：普通消息 1：保留消息 参数4：`<payload>`数据内容(最大长度为1024个字节) ```c AT+MQTTPUB=topic,0,0,hello bw16 // 发送消息 [AI_MqttAppPublishMessage()-2097]Publish Topic topic:0 [AI_MqttAppPublishMessage()-2132]Qos0 not need Ack OK [MEM] After do cmd, available heap 103136 [AI_MqttDataHandle()-1555]Read packet type is PUBLISH [AI_MqttMessageArrived()-2140]Message arrived +EVENT:MQTT_SUB,topic,11,hello bw16 // 接收消息 ``` 客户端显示  # 05 取消订阅 命令： `AT+MQTTUNSUB=<topic>` 参数1：`<topic>`要取消订阅的主题 ```c AT+MQTTUNSUB=topic [AI_MqttDataHandle()-1555]Read packet type is UNSUBACK [AI_MqttDataHandle()-1697]topic:topic set AI_MQTT_RECIVE_UNSUBACK [AI_MqttAppUnsubscribeTopic()-2308]recive UnSubscribe ack,UnSubscribe success OK [MEM] After do cmd, available heap 103200 ``` 取消订阅成功

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我这边发AT+MQTT=5时，模组会重置，是什么原因呀？

json 的消息如何发布呀