fix: 发货审核异常未回滚导致的脏数据，添加判空操作

gongchunyi

昨天 2aa97d1237b7f720b33f9952f9901ddf7ae9833a

 src/main/java/com/ruoyi/warehouse/service/DocumentClassificationService.java

@@ -16,5 +16,5 @@

    boolean deleteByIds(List<Long> ids);

    List<DocumentClassificationTreeDto> selectDocumentClassificationList(DocumentClassificationDto documentClassificationDto);
    List<DocumentClassificationTreeDto> selectDocumentClassificationList();
}