说明：  1.设计一个简单的学生管理系统（StudentManager）。主要功能包括： (1)学生信息的录入。主要包括：学号（no）、姓名（name）、年龄（age）、性别（gender）等； (2)学生信息的查询。根据学号、姓名、年龄和性别等查询学生的信息。注意：查询结果可能不唯一。 (3)学生信息的修改。根据学号查询到指定学生的信息，再用新的内容替换。 (4)学生信息的删除。根据学号删除指定学生的信息。 设计时，采用层次化设计法，将类分为界面层（ui）、功能层（business）和持久层（persistence）3层，放在不同子包中。整个系统的代码放在exe4_1包中。
(1. Design a simple student management system (StudentManager). Key features include: (1) The entry of student information. Including: Student ID (no), name (name), aged (age), sex (gender) and the like (2) query the student information. According to school, name, age and sex inquiry student information. Note: query results may not be unique. (3) amend the student information. Query based on student number to the designated student information, and then replaced with new content. (4) delete student information. Designated students with information based on student number removed. Design, the use of hierarchical design method, the class is divided into the interface layer (ui), the functional layer (business) and persistence (persistence) 3 layers in different sub-packages. The system code in the exe4_1 package.)