用例图：
reader借书续借图书查询个人信息查询借阅信息查询还书管理读者信息管理图书信息admin
时序图： 读者登录：
readeruser_login.jspuser_index.jspLoginUServlet : UserBLM : UserDAO : DBPool1: 2: doPost()3: loginUser( )4: loginUser( )5: getConnection( )6: 7: 8: 9:
管理员登录：
adminadmin_login.jspadmin_index.jspLoginAServlet : AdminBLm : AdminDAO : DBPool1: 2: doPost()3: loginAdmin( )4: loginAdmin( )5: getConnection( )6: 7: 8: 9:
1. 借书
adminborrow.jspresult.jsp : BorrowServlet : BorrowBean : BorrowBLM : BorrowDAO : DBPool1: 2: dopost( )3: borrow()4: addBorrow()5: getConnection( )6: 7: 8: 9: 10: 11:
2. 续借
admin1: 2: dopost( )3: xborrow()4: xBorrow()5: getConnection( )6: 7: 8: 9: 10: 11: xborrow.jspresult.jsp : BorrowServlet : BorrowBean : BorrowBLM : BorrowDAO : DBPool
3. 还书
admin1: rtborrow.jspresult.jsp : RtborrowServlet : BorrowBean : BorrowBLM : BorrowDAO : DBPool2: dopost()3: rtborrow()4: rtBorrow()5: getConnection( )6: 7: 8: 9: 10: 11:
4. 查询借书信息
admin1: query.jspresult.jsp : QueryServlet : BorrowBean : BorrowBLM : BorrowDAO : DBPool2: dopost( )3: query()4: borrow()5: getConnection( )6: 7: 8: 9: 10: 11:
5. 添加图书
adminbook/addbook.jspbresult.jsp : AddServlet : BookBean : BookBLM : BookDAO : DBPool1: 2: doPost( )3: addbook( )4: addBook( )5: getConnection( )6: 7: 8: 9: 10: 11:
6. 删除图书
