利用jdk做一个学生管理系统

学生管理系统可以分为三个模块：学生信息管理、课程管理和成绩管理。下面是一个简单的学生管理系统的示例代码。

1. 学生信息管理模块

import java.util.ArrayList;

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

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

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getGender() {
        return gender;
    }

    public String getId() {
        return id;
    }

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

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

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

public class StudentManager {
    private ArrayList<Student> students;

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

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

    public void removeStudent(Student student) {
        students.remove(student);
    }

    public Student findStudentById(String id) {
        for (Student student : students) {
            if (student.getId().equals(id)) {
                return student;
            }
        }
        return null;
    }
}

2. 课程管理模块

import java.util.ArrayList;

public class Course {
    private String name;
    private String id;
    private ArrayList<String> students;

    public Course(String name, String id) {
        this.name = name;
        this.id = id;
        students = new ArrayList<String>();
    }

    public String getName() {
        return name;
    }

    public String getId() {
        return id;
    }

    public ArrayList<String> getStudents() {
        return students;
    }

    public void addStudent(String studentId) {
        students.add(studentId);
    }

    public void removeStudent(String studentId) {
        students.remove(studentId);
    }
}

public class CourseManager {
    private ArrayList<Course> courses;

    public CourseManager() {
        courses = new ArrayList<Course>();
    }

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

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

    public Course findCourseById(String id) {
        for (Course course : courses) {
            if (course.getId().equals(id)) {
                return course;
            }
        }
        return null;
    }
}

3. 成绩管理模块

import java.util.HashMap;

public class Grade {
    private String studentId;
    private String courseId;
    private HashMap<String, Double> scores;

    public Grade(String studentId, String courseId) {
        this.studentId = studentId;
        this.courseId = courseId;
        scores = new HashMap<String, Double>();
    }

    public String getStudentId() {
        return studentId;
    }

    public String getCourseId() {
        return courseId;
    }

    public HashMap<String, Double> getScores() {
        return scores;
    }

    public void addScore(String item, double score) {
        scores.put(item, score);
    }

    public void removeScore(String item) {
        scores.remove(item);
    }
}

public class GradeManager {
    private ArrayList<Grade> grades;

    public GradeManager() {
        grades = new ArrayList<Grade>();
    }

    public void addGrade(Grade grade) {
        grades.add(grade);
    }

    public void removeGrade(Grade grade) {
        grades.remove(grade);
    }

    public Grade findGradeByStudentAndCourse(String studentId, String courseId) {
        for (Grade grade : grades) {
            if (grade.getStudentId().equals(studentId) && grade.getCourseId().equals(courseId)) {
                return grade;
            }
        }
        return null;
    }
}

这些代码可以进一步组合成一个完整的学生管理系统。在这个系统中，用户可以添加和删除学生、课程和成绩，也可以查询学生的课程和成绩信息。