leftNum

service/book/book.go

 			utils.LogError("借阅失败: " + err.Error())
 			return nil, errors.New("借阅失败")
 		}
+		if book.LeftNum <= 0 {
+			utils.LogError("该图书已无库存: " + err.Error())
+			return nil, errors.New("该图书已无库存")
+		}
 		var borrowRecord = model.TaBookBorrowRecord{
 			BookId:        bookId,
 			BorrowStatus:  models.BORROW_TYPE_BORROWED,