Chirpstack配置MQTT.fx

1.Chirpstack运行后，默认是开启了MQTT服务的，无需手动打开。直接用MQTT客户端连接即可。

2.订阅LoRa节点发过来的消息（上行消息）

（1）订阅所有消息（注意全部小写）topic：application/{application id}/#，如application/1/#

（2）订阅指定上行消息（注意全部小写）topic：application/[ApplicationID]/device/[DevEUI]/event/[EventType]，如application/1/device/70b3d57ed0056427/event/up

3.给LoRa节点发消息topic:

application/[ApplicationID]/device/[DevEUI]/command/down，

如application/1/device/70b3d57ed0056427/command/down。

消息体为:

{
"devEui": "70b3d57ed0056427",
"confirmed": true,
"fPort": 10,
"data": "qrvM"
}