增加二维码.备注功能

src/main/java/com/zy/bms/handler/MqttCallbackHandler.java

@@ -90,8 +90,11 @@ public class MqttCallbackHandler {
         if (dbData != null) {
             device.setId(dbData.getId());
         }
+        //只有第一次注册,才会生成二维码
+        if (dbData==null){
+            device.setQrCode(QRCodeUtil.generate(openNum));
+        }
         device.setOpenNum(openNum);
-        device.setQrCode(QRCodeUtil.generate(openNum));
         device.setGroupId(mqttDTO.getString("group"));
         device.setUsername(Constant.PREF.RABBIT_MQ_USERNAME + openNum);
         device.setPassword(MD5Util.encode(openNum));