删除书籍前取消书籍与文件的关联

bookshelfplus/src/main/java/plus/bookshelf/Service/Service/FileService.java

@@ -43,6 +43,13 @@ public interface FileService {
      */
     Boolean addFile(FileModel fileModel) throws InvocationTargetException, IllegalAccessException;
 
+    /**
+     * 取消文件和书籍的关联
+     *
+     * @return
+     */
+    Integer unbindBook(Integer bookId);
+
     /**
      * 获取上一步添加的文件Id
      *