关于用户管理的模块。主要功能为管理员登陆后对用户进行添加，删除和修改操作。用到javabean连接数据库和执行sql语句、resultset显示数据以及session记录登陆状态。-On the user management module. Main function as an administrator after landing on the user add, delete and modify operations. JavaBean used to connect databases and the implementation of sql statement, resultset display data as well as the session state record of landing.