用java编写一个学生成绩管理系统。学生的属性包括学号、姓名、年龄等。每个学生要学习若干课程,每门课程有平时成绩、其中考试成绩、实习成绩、期末考试成绩以及总评成绩等多个成绩,其中平时成绩的数目不定

以下是一个简单的学生成绩管理系统的Java代码示例：

import java.util.ArrayList;
import java.util.Scanner;

public class StudentGradeSystem {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        ArrayList<Student> students = new ArrayList<Student>();

        while (true) {
            System.out.println("请输入操作编号：");
            System.out.println("1. 添加学生");
            System.out.println("2. 删除学生");
            System.out.println("3. 修改学生信息");
            System.out.println("4. 查询学生信息");
            System.out.println("5. 退出系统");
            int choice = sc.nextInt();
            switch (choice) {
                case 1:
                    addStudent(students, sc);
                    break;
                case 2:
                    deleteStudent(students, sc);
                    break;
                case 3:
                    modifyStudent(students, sc);
                    break;
                case 4:
                    queryStudent(students, sc);
                    break;
                case 5:
                    System.out.println("谢谢使用！");
                    System.exit(0);
                default:
                    System.out.println("输入有误，请重新输入！");
                    break;
            }
        }
    }

    // 添加学生
    public static void addStudent(ArrayList<Student> students, Scanner sc) {
        System.out.println("请输入学号：");
        String id = sc.next();
        System.out.println("请输入姓名：");
        String name = sc.next();
        System.out.println("请输入年龄：");
        int age = sc.nextInt();

        Student student = new Student(id, name, age);

        System.out.println("请输入该学生选修课程的数量：");
        int courseNum = sc.nextInt();
        for (int i = 0; i < courseNum; i++) {
            System.out.println("请输入第" + (i+1) + "门课程的名称：");
            String courseName = sc.next();
            System.out.println("请输入该课程的平时成绩数目：");
            int dailyScoreNum = sc.nextInt();

            Course course = new Course(courseName);

            for (int j = 0; j < dailyScoreNum; j++) {
                System.out.println("请输入该课程的第" + (j+1) + "个平时成绩：");
                double dailyScore = sc.nextDouble();
                course.addDailyScore(dailyScore);
            }

            System.out.println("请输入该课程的期中考试成绩：");
            double midtermScore = sc.nextDouble();
            course.setMidtermScore(midtermScore);

            System.out.println("请输入该课程的实习成绩：");
            double internshipScore = sc.nextDouble();
            course.setInternshipScore(internshipScore);

            System.out.println("请输入该课程的期末考试成绩：");
            double finalScore = sc.nextDouble();
            course.setFinalScore(finalScore);

            student.addCourse(course);
        }

        students.add(student);
        System.out.println("添加成功！");
    }

    // 删除学生
    public static void deleteStudent(ArrayList<Student> students, Scanner sc) {
        System.out.println("请输入要删除的学生的学号：");
        String id = sc.next();

        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                students.remove(i);
                System.out.println("删除成功！");
                return;
            }
        }

        System.out.println("该学号对应的学生不存在！");
    }

    // 修改学生信息
    public static void modifyStudent(ArrayList<Student> students, Scanner sc) {
        System.out.println("请输入要修改的学生的学号：");
        String id = sc.next();

        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                System.out.println("请输入新的姓名：");
                String name = sc.next();
                System.out.println("请输入新的年龄：");
                int age = sc.nextInt();

                students.get(i).setName(name);
                students.get(i).setAge(age);

                System.out.println("修改成功！");
                return;
            }
        }

        System.out.println("该学号对应的学生不存在！");
    }

    // 查询学生信息
    public static void queryStudent(ArrayList<Student> students, Scanner sc) {
        System.out.println("请输入要查询的学生的学号：");
        String id = sc.next();

        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                System.out.println("学号：" + students.get(i).getId());
                System.out.println("姓名：" + students.get(i).getName());
                System.out.println("年龄：" + students.get(i).getAge());
                System.out.println("选修课程：");

                ArrayList<Course> courses = students.get(i).getCourses();
                for (int j = 0; j < courses.size(); j++) {
                    System.out.println("课程名称：" + courses.get(j).getName());
                    System.out.println("平时成绩：");
                    ArrayList<Double> dailyScores = courses.get(j).getDailyScores();
                    for (int k = 0; k < dailyScores.size(); k++) {
                        System.out.println("第" + (k+1) + "个平时成绩：" + dailyScores.get(k));
                    }
                    System.out.println("期中考试成绩：" + courses.get(j).getMidtermScore());
                    System.out.println("实习成绩：" + courses.get(j).getInternshipScore());
                    System.out.println("期末考试成绩：" + courses.get(j).getFinalScore());
                    System.out.println("总评成绩：" + courses.get(j).getTotalScore());
                }

                return;
            }
        }

        System.out.println("该学号对应的学生不存在！");
    }
}

class Student {
    private String id;
    private String name;
    private int age;
    private ArrayList<Course> courses;

    public Student(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.courses = new ArrayList<Course>();
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public ArrayList<Course> getCourses() {
        return courses;
    }

    public void addCourse(Course course) {
        courses.add(course);
    }

    public void removeCourse(Course course) {
        courses.remove(course);
    }
}

class Course {
    private String name;
    private ArrayList<Double> dailyScores;
    private double midtermScore;
    private double internshipScore;
    private double finalScore;
    private double totalScore;

    public Course(String name) {
        this.name = name;
        this.dailyScores = new ArrayList<Double>();
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public ArrayList<Double> getDailyScores() {
        return dailyScores;
    }

    public void addDailyScore(double score) {
        dailyScores.add(score);
    }

    public double getMidtermScore() {
        return midtermScore;
    }

    public void setMidtermScore(double midtermScore) {
        this.midtermScore = midtermScore;
    }

    public double getInternshipScore() {
        return internshipScore;
    }

    public void setInternshipScore(double internshipScore) {
        this.internshipScore = internshipScore;
    }

    public double getFinalScore() {
        return finalScore;
    }

    public void setFinalScore(double finalScore) {
        this.finalScore = finalScore;
    }

    public double getTotalScore() {
        totalScore = 0;
        for (int i = 0; i < dailyScores.size(); i++) {
            totalScore += dailyScores.get(i);
        }
        totalScore += midtermScore + internshipScore + finalScore;
        return totalScore;
    }
}

这个例子中，我们定义了两个类，`Student` 和 `Course`，用于表示学生和课程。`Student` 类包含一个学生的基本信息（学号、姓名、年龄）和选修课程（用一个 `ArrayList` 存储）。`Course` 类包含一个课程的基本信息（名称）和各项成绩（平时成绩、期中考试成绩、实习成绩、期末考试成绩、总评成绩）。

在 `main` 函数中，我们使用一个 `ArrayList` 存储所有学生的信息，并通过一个无限循环来实现菜单式的操作。用户可以输入对应的编号来执行不同的操作，包括添加学生、删除学生、修改学生信息和查询学生信息。

在添加学生时，我们先输入学生的基本信息，然后再输入该学生选修课程的数量。对于每门课程，我们输入名称和平时成绩数目，然后分别输入各项成绩，并将其添加到该学生的选修课程中。

在删除学生、修改学生信息和查询学生信息时，我们都需要先输入要操作的学生的学号，然后通过遍历 `ArrayList` 来找到对应的学生，进行相应的操作。

以上是一个基本的学生成绩管理系统的Java代码示例，可以根据需要进行修改和完善。