Java로 간단한 학생 활동 등록 시스템을 설계하는 방법은 무엇입니까?

public class Student {
    private int id;
    private String name;
    private int grade;

    public Student(int id, String name, int grade) {
        this.id = id;
        this.name = name;
        this.grade = grade;
    }

    // getter和setter方法

    // 其他操作方法，如打印学生信息等
}

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

public class StudentManager {
    private List<Student> studentList;

    public StudentManager() {
        studentList = new ArrayList<>();
    }

    public void addStudent(Student student) {
        studentList.add(student);
    }

    public void deleteStudent(int id) {
        for (Student student : studentList) {
            if (student.getId() == id) {
                studentList.remove(student);
                break;
            }
        }
    }

    public void updateStudent(int id, Student newStudent) {
        for (int i = 0; i < studentList.size(); i++) {
            if (studentList.get(i).getId() == id) {
                studentList.set(i, newStudent);
                break;
            }
        }
    }

    // 其他操作方法，如根据学号查询学生信息等
}

public class Test {
    public static void main(String[] args) {
        Student student1 = new Student(1, "Tom", 1);
        Student student2 = new Student(2, "Jerry", 2);

        StudentManager studentManager = new StudentManager();
        studentManager.addStudent(student1);
        studentManager.addStudent(student2);

        studentManager.deleteStudent(1);

        Activity activity = new Activity("Basketball", "2022-01-01", "Gym");

        ActivityManager activityManager = new ActivityManager();
        activityManager.addActivity(activity);

        Enrollment enrollment = new Enrollment(student2, activity);

        EnrollmentManager enrollmentManager = new EnrollmentManager();
        enrollmentManager.addEnrollment(enrollment);

        // 其他操作和测试代码
    }
}