利用Map实现对学生成绩进行管理，其中以每一个学生的学号作为Key，创建一个学生成绩记录类，属性包括学生姓名(字符型)，学生性别 (字符型)，学生专业(字符型)，个人作业成绩（满分45分），小组作业成绩（满分50分），出勤分（满分5分）。以学生记录对象作为value，实现以下操作：

(1)添加一个学生成绩记录；

(2)删除一个学生成绩记录；

(3)根据学生学号，查询并输出其相应的学生成绩信息；

(4)用户可以输入命令，计算所有学生成绩的总分的平均分数，并输出最高分，最低分，各个分数段（90-100,80-89,70-79,60-69，0-59）的人数；

（1）要求程序中事先产生若干学生成绩

（2）你还可以增加其它功能。程序中应该增加必要的异常处理（例如分数输入错误等）。

-Map achieve student achievement by the management, of which each student s Student ID as the Key, to create a record of student achievement category, is

Of including the student name (character), student gender (character), Student (Character), individual job performance (out of 45 points)

Group operating result (out of 50 points), attendance (out of 5). Student record object as value, to achieve the following:

(1) add a record of student achievement

(2) Delete a record of student achievement

(3) According to the students to learn numbers, query and output the corresponding information on student achievement

(4) The user can enter the command, calculate the total score of all the average student achievement scores, and outputs the highest score, lowest score, all scores section

(90-100,80-89,70-79,60-69,0-59) number

(1) requires procedures have a number of students in grades pre-

(2) You can also add other features. Program should be to increase the necessary exception han