【fix sonar】SysDepartPermissionServiceImpl文件

jero-boot/jero-boot-module-system/src/main/java/com/jero/modules/system/service/impl/SysDepartPermissionServiceImpl.java

@@ -59,7 +59,7 @@ public class SysDepartPermissionServiceImpl extends ServiceImpl<SysDepartPermiss
 //            List<SysPermissionDataRule> permRuleList = this.ruleMapper.selectList(query);
             return this.ruleMapper.selectList(query);
         }else{
-            return null;
+            return Collections.emptyList();
         }
     }
 
@@ -71,7 +71,7 @@ public class SysDepartPermissionServiceImpl extends ServiceImpl<SysDepartPermiss
      */
     private List<String> getDiff(String main,String diff){
         if(oConvertUtils.isEmpty(diff)) {
-            return null;
+            return Collections.emptyList();
         }
         if(oConvertUtils.isEmpty(main)) {
             return Arrays.asList(diff.split(","));