说明：  图书管理系统 带数据库源码 【JAVA MVC】 即把一个应用的输入、处理、输出流程按照Model、View、Controller的方式进行分离，这样一个应用被分成三个层——模型层、视图层、控制层。
(Library Management System with Database Source Code [JAVA MVC] That is to say, the input, processing and output processes of an application are separated according to the mode of Model, View and Controller. Such an application is divided into three layers: model layer, view layer and control layer.)