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（因为不同课程的教师布置的平时作业不同），而总评成绩是其它成绩的平均值。请先设计合理的类存放这些信息，然后设计程序完成以下功能： （1）列出某个学生的所有成绩； （2）列出某门课程每个学生的总评成绩，及所有学生总评成绩的总评分； （3）分区段统计某门课程的学生总评成绩，例如60分以下的学生人数、60至70分的学生人数等。

好的，下面是我为您提供的Java代码：

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

public class StudentGradeManagementSystem {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        List<Student> students = new ArrayList<>(); // 存储学生信息
        List<Course> courses = new ArrayList<>(); // 存储课程信息

        // 添加学生信息
        System.out.print("请输入学生数：");
        int numStudents = input.nextInt();
        for (int i = 0; i < numStudents; i++) {
            System.out.print("请输入第" + (i+1) + "个学生的信息：");
            System.out.print("学号：");
            String id = input.next();
            System.out.print("姓名：");
            String name = input.next();
            System.out.print("年龄：");
            int age = input.nextInt();
            students.add(new Student(id, name, age));
        }

        // 添加课程信息
        System.out.print("请输入课程数：");
        int numCourses = input.nextInt();
        for (int i = 0; i < numCourses; i++) {
            System.out.print("请输入第" + (i+1) + "门课程的信息：");
            System.out.print("课程名称：");
            String name = input.next();
            System.out.print("平时成绩占比（例如0.3表示30%）：");
            double dailyScoreWeight = input.nextDouble();
            System.out.print("其中考试成绩占比：");
            double examScoreWeight = input.nextDouble();
            System.out.print("实习成绩占比：");
            double practiceScoreWeight = input.nextDouble();
            System.out.print("期末考试成绩占比：");
            double finalScoreWeight = input.nextDouble();
            courses.add(new Course(name, dailyScoreWeight, examScoreWeight, practiceScoreWeight, finalScoreWeight));
        }

        // 输入每个学生的课程成绩
        for (Student student : students) {
            System.out.print("请输入学生" + student.getName() + "的各科成绩：");
            for (Course course : courses) {
                System.out.print(course.getName() + "的平时成绩数目：");
                int numDailyScore = input.nextInt();
                List<Double> dailyScores = new ArrayList<>();
                for (int i = 0; i < numDailyScore; i++) {
                    System.out.print("第" + (i+1) + "个平时成绩：");
                    dailyScores.add(input.nextDouble());
                }
                System.out.print(course.getName() + "的其中考试成绩：");
                double examScore = input.nextDouble();
                System.out.print(course.getName() + "的实习成绩：");
                double practiceScore = input.nextDouble();
                System.out.print(course.getName() + "的期末考试成绩：");
                double finalScore = input.nextDouble();
                student.addCourseScore(course, dailyScores, examScore, practiceScore, finalScore);
            }
        }

        // 列出某个学生的所有成绩
        System.out.print("请输入要查询成绩的学生姓名：");
        String name = input.next();
        for (Student student : students) {
            if (student.getName().equals(name)) {
                System.out.println(student);
            }
        }

        // 列出某门课程每个学生的总评成绩，及所有学生总评成绩的总评分
        System.out.print("请输入要查询总评成绩的课程名称：");
        String courseName = input.next();
        Course course = null;
        for (Course c : courses) {
            if (c.getName().equals(courseName)) {
                course = c;
                break;
            }
        }
        if (course == null) {
            System.out.println("未找到该课程！");
            return;
        }
        double totalScore = 0;
        int numStudentsWithScore = 0;
        for (Student student : students) {
            double score = student.getScore(course);
            if (score != -1) {
                System.out.println(student.getName() + "的" + course.getName() + "总评成绩为：" + score);
                totalScore += score;
                numStudentsWithScore++;
            }
        }
        double averageScore = totalScore / numStudentsWithScore;
        System.out.println("所有学生的" + course.getName() + "总评成绩的总评分为：" + averageScore);

        // 分区段统计某门课程的学生总评成绩
        System.out.print("请输入要查询的课程名称：");
        courseName = input.next();
        course = null;
        for (Course c : courses) {
            if (c.getName().equals(courseName)) {
                course = c;
                break;
            }
        }
        if (course == null) {
            System.out.println("未找到该课程！");
            return;
        }
        System.out.print("请输入分数段的个数：");
        int numSections = input.nextInt();
        double[] sectionScores = new double[numSections+1];
        sectionScores[0] = 0; // 分数段的下限
        sectionScores[numSections] = 100; // 分数段的上限
        for (int i = 1; i < numSections; i++) {
            System.out.print("请输入第" + i + "个分数段的下限：");
            sectionScores[i] = input.nextDouble();
        }
        int[] numStudentsInSection = new int[numSections+1];
        for (Student student : students) {
            double score = student.getScore(course);
            if (score != -1) {
                for (int i = 0; i < numSections; i++) {
                    if (score >= sectionScores[i] && score < sectionScores[i+1]) {
                        numStudentsInSection[i]++;
                        break;
                    }
                }
            }
        }
        for (int i = 0; i < numSections; i++) {
            System.out.println(sectionScores[i] + "到" + sectionScores[i+1] + "分的学生人数为：" + numStudentsInSection[i]);
        }
    }
}

class Student {
    private String id;
    private String name;
    private int age;
    private List<CourseScore> courseScores;

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

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public void addCourseScore(Course course, List<Double> dailyScores, double examScore, double practiceScore, double finalScore) {
        this.courseScores.add(new CourseScore(course, dailyScores, examScore, practiceScore, finalScore));
    }

    public double getScore(Course course) {
        for (CourseScore courseScore : courseScores) {
            if (courseScore.getCourse().equals(course)) {
                return courseScore.getScore();
            }
        }
        return -1;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        for (CourseScore courseScore : courseScores) {
            sb.append(courseScore.getCourse().getName()).append("成绩：").append(courseScore.getScore()).append("\n");
        }
        return sb.toString();
    }
}

class Course {
    private String name;
    private double dailyScoreWeight;
    private double examScoreWeight;
    private double practiceScoreWeight;
    private double finalScoreWeight;

    public Course(String name, double dailyScoreWeight, double examScoreWeight, double practiceScoreWeight, double finalScoreWeight) {
        this.name = name;
        this.dailyScoreWeight = dailyScoreWeight;
        this.examScoreWeight = examScoreWeight;
        this.practiceScoreWeight = practiceScoreWeight;
        this.finalScoreWeight = finalScoreWeight;
    }

    public String getName() {
        return name;
    }

    public double getDailyScoreWeight() {
        return dailyScoreWeight;
    }

    public double getExamScoreWeight() {
        return examScoreWeight;
    }

    public double getPracticeScoreWeight() {
        return practiceScoreWeight;
    }

    public double getFinalScoreWeight() {
        return finalScoreWeight;
    }
}

class CourseScore {
    private Course course;
    private List<Double> dailyScores;
    private double examScore;
    private double practiceScore;
    private double finalScore;

    public CourseScore(Course course, List<Double> dailyScores, double examScore, double practiceScore, double finalScore) {
        this.course = course;
        this.dailyScores = dailyScores;
        this.examScore = examScore;
        this.practiceScore = practiceScore;
        this.finalScore = finalScore;
    }

    public Course getCourse() {
        return course;
    }

    public double getScore() {
        double dailyScoreSum = 0;
        for (double dailyScore : dailyScores) {
            dailyScoreSum += dailyScore;
        }
        double dailyScoreAverage = dailyScoreSum / dailyScores.size();
        return dailyScoreAverage * course.getDailyScoreWeight() +
                examScore * course.getExamScoreWeight() +
                practiceScore * course.getPracticeScoreWeight() +
                finalScore * course.getFinalScoreWeight();
    }
}

以上代码实现了一个学生成绩管理系统，包括学生信息、课程信息和课程成绩信息。每个学生可以学习多门课程，每门课程有多个成绩，包括平时成绩、其中考试成绩、实习成绩、期末考试成绩以及总评成绩等。可以实现以下功能：

1. 列出某个学生的所有成绩；
2. 列出某门课程每个学生的总评成绩，及所有学生总评成绩的总评分；
3. 分区段统计某门课程的学生总评成绩。