diff --git a/book_manager.py b/book_manager.py
index c1018fa..11b7674 100644
--- a/book_manager.py
+++ b/book_manager.py
@@ -5,6 +5,9 @@ from datetime import datetime
 class BookManager:
     """图书管理类，负责图书信息的增删改查操作"""
     
+    def __init__(self, data_file='books.json'):
+        """初始化图书管理器，加载已有图书数据"""
+        self.data_file = data_file
     
     def _load_books(self):
         """从文件加载图书数据"""