fix: 优化代码

pom.xml

@@ -74,12 +74,6 @@
             <version>3.5.0</version>
         </dependency>
 
-        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
-        <dependency>
-            <groupId>com.alibaba</groupId>
-            <artifactId>druid</artifactId>
-            <version>1.1.21</version>
-        </dependency>
 
         <!--数据连接池druid-->
         <dependency>

src/main/java/com/xydl/service/impl/MqttServiceImpl.java

@@ -53,6 +53,7 @@ public class MqttServiceImpl {
         }
         log.info("表{},共{}个设备", tableName, dataEqmids.size());
 
+        if (dataEqmids.size() > 0) {
             mqttUtil.connect();
             for (int deviceID : dataEqmids) {
                 Object time = devIDLastTimeMap.get(deviceID);
@@ -64,6 +65,7 @@ public class MqttServiceImpl {
             }
             mqttUtil.disconnect();
         }
+    }
 
     //推送单个设备数据
     public void publishData(String deviceID, String time, String sqlExecuting, String tableName, Map<String, String> fieldMap) {