rev:opc读取float类型防呆优化

acs2/nladmin-system/nlsso-server/src/main/java/org/nl/acs/device_driver/driver/OpcDeviceDriver.java

@@ -158,7 +158,14 @@ public interface OpcDeviceDriver extends DeviceDriver {
      * @return
      */
     default Float getFloatValue(String protocol) {
-        return (Float) this.getOpcValueAccessor().getValue(this.getItem(protocol));
+        Object value = this.getOpcValueAccessor().getValue(this.getItem(protocol));
+        if (ObjectUtil.isEmpty(value)) {
+            return null;
+        }
+        if (value instanceof Number) {
+            return ((Number) value).floatValue();
+        }
+        return Float.valueOf(value.toString());
     }
 
     /**