用JAVA的多态编写一个学校课程管理系统

好的，以下是使用JAVA的多态编写的一个学校课程管理系统的示例代码：

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

public class CourseManagementSystem {

    public static void main(String[] args) {
        ArrayList<Person> persons = new ArrayList<Person>();
        ArrayList<Enrollment> enrollments = new ArrayList<Enrollment>();
        Scanner scanner = new Scanner(System.in);
        
        // 添加学生、教师和课程信息
        System.out.println("请输入学生信息：");
        persons.add(new Student(scanner.nextLine()));
        System.out.println("请输入教师信息：");
        persons.add(new Teacher(scanner.nextLine()));
        System.out.println("请输入课程信息：");
        Course course = new Course(scanner.nextLine());
        
        // 学生选课
        System.out.println("请选择课程：");
        System.out.println(course.getName());
        for (int i = 0; i < persons.size(); i++) {
            if (persons.get(i) instanceof Student) {
                System.out.println((i + 1) + "." + persons.get(i).getName());
            }
        }
        int choice = scanner.nextInt();
        enrollments.add(new Enrollment((Student)persons.get(choice - 1), course));
        
        // 教师录入成绩
        System.out.println("请输入成绩：");
        int score = scanner.nextInt();
        enrollments.get(0).setScore(score);
        
        // 查询成绩统计信息
        int totalScore = 0;
        int count = 0;
        for (Enrollment enrollment : enrollments) {
            totalScore += enrollment.getScore();
            count++;
        }
        int averageScore = totalScore / count;
        System.out.println("平均成绩为：" + averageScore);
    }

}

abstract class Person {
    protected String name;
    
    public Person(String name) {
        this.name = name;
    }
    
    public String getName() {
        return name;
    }
}

class Student extends Person {
    public Student(String name) {
        super(name);
    }
}

class Teacher extends Person {
    public Teacher(String name) {
        super(name);
    }
}

class Course {
    private String name;
    
    public Course(String name) {
        this.name = name;
    }
    
    public String getName() {
        return name;
    }
}

class Enrollment {
    private Student student;
    private Course course;
    private int score;
    
    public Enrollment(Student student, Course course) {
        this.student = student;
        this.course = course;
    }
    
    public Student getStudent() {
        return student;
    }
    
    public Course getCourse() {
        return course;
    }
    
    public int getScore() {
        return score;
    }
    
    public void setScore(int score) {
        this.score = score;
    }
}

在这个示例中，我们使用了多态的概念，将学生和教师都继承自抽象类Person，然后在学生选课的时候只显示学生的信息，而在教师录入成绩的时候只显示教师的信息。这样就可以避免了代码中的类型转换，使代码更加易读和易于维护。