使用Servlet实现简单的用户管理(增删改查，分页)，并使用到了ajax技术实现增删改查，分页完全不刷新，主要是为了改善用户体验。-Servlet implementation using a simple user management (CRUD, paging), and using ajax technology to achieve CRUD, paging completely refreshed, mainly in order to improve the user exper