设计Person类， （1）包含姓名(String)、性别(String)和年龄(int)成员变量，以及相应的getter和setter方法。 (2) 至少实现一个构造方法 （3）重写toString方法，输出Person对象信息； 2. 以Person为父类，设计一个学生类Student， （1）增加学号(int)、班级(String)、英语成绩、数学成绩和java成绩 这几个成员变量，以相应的getter和setter方法。 (2) 至少实现一个构造方法 (3) 重写toString()方法，输出Student对象信息。 3. 设计一个测试类StudentDemo，包含成员变量List<Student> students; 在main()方法中，调用并实现： （1）添加学生方法addStudents，实现从键盘输入学生信息，创建学生对象，添加到students 。 （2）删除学生方法delStudents，根据从键盘输入的学号信息，从students 删除该学生对象。 （3）输入成绩方法inputScore，从键盘为不同学生输入英语、数学和java成绩。 （4）输出成绩方法outScore， 输出students中所有学生的基本信息、3门课程成绩和平均成绩

Person类：

public class Person {
    private String name;
    private String gender;
    private int age;

    public Person() {
    }

    public Person(String name, String gender, int age) {
        this.name = name;
        this.gender = gender;
        this.age = age;
    }

    public String getName() {
        return name;
    }

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

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

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

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                '}';
    }
}

Student类：

public class Student extends Person {
    private int id;
    private String clazz;
    private double englishScore;
    private double mathScore;
    private double javaScore;

    public Student() {
    }

    public Student(int id, String clazz, double englishScore, double mathScore, double javaScore) {
        this.id = id;
        this.clazz = clazz;
        this.englishScore = englishScore;
        this.mathScore = mathScore;
        this.javaScore = javaScore;
    }

    public int getId() {
        return id;
    }

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

    public String getClazz() {
        return clazz;
    }

    public void setClazz(String clazz) {
        this.clazz = clazz;
    }

    public double getEnglishScore() {
        return englishScore;
    }

    public void setEnglishScore(double englishScore) {
        this.englishScore = englishScore;
    }

    public double getMathScore() {
        return mathScore;
    }

    public void setMathScore(double mathScore) {
        this.mathScore = mathScore;
    }

    public double getJavaScore() {
        return javaScore;
    }

    public void setJavaScore(double javaScore) {
        this.javaScore = javaScore;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", clazz='" + clazz + '\'' +
                ", englishScore=" + englishScore +
                ", mathScore=" + mathScore +
                ", javaScore=" + javaScore +
                "} " + super.toString();
    }
}

StudentDemo类：

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

public class StudentDemo {
    private List<Student> students;

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

    public void addStudents() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生姓名：");
        String name = scanner.nextLine();
        System.out.println("请输入学生性别：");
        String gender = scanner.nextLine();
        System.out.println("请输入学生年龄：");
        int age = scanner.nextInt();
        System.out.println("请输入学生学号：");
        int id = scanner.nextInt();
        scanner.nextLine();
        System.out.println("请输入学生班级：");
        String clazz = scanner.nextLine();
        System.out.println("请输入学生英语成绩：");
        double englishScore = scanner.nextDouble();
        System.out.println("请输入学生数学成绩：");
        double mathScore = scanner.nextDouble();
        System.out.println("请输入学生Java成绩：");
        double javaScore = scanner.nextDouble();
        Student student = new Student(id, clazz, englishScore, mathScore, javaScore);
        student.setName(name);
        student.setGender(gender);
        student.setAge(age);
        students.add(student);
    }

    public void delStudents() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入要删除的学生学号：");
        int id = scanner.nextInt();
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId() == id) {
                students.remove(i);
                System.out.println("删除成功！");
                break;
            }
        }
    }

    public void inputScore() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生学号：");
        int id = scanner.nextInt();
        for (Student student : students) {
            if (student.getId() == id) {
                System.out.println("请输入学生英语成绩：");
                double englishScore = scanner.nextDouble();
                student.setEnglishScore(englishScore);
                System.out.println("请输入学生数学成绩：");
                double mathScore = scanner.nextDouble();
                student.setMathScore(mathScore);
                System.out.println("请输入学生Java成绩：");
                double javaScore = scanner.nextDouble();
                student.setJavaScore(javaScore);
                System.out.println("成绩输入成功！");
                return;
            }
        }
        System.out.println("找不到该学生！");
    }

    public void outScore() {
        for (Student student : students) {
            System.out.println(student.getName() + "：" + student.getEnglishScore() + " " + student.getMathScore() + " " + student.getJavaScore() + " 平均分：" + (student.getEnglishScore() + student.getMathScore() + student.getJavaScore()) / 3);
        }
    }

    public static void main(String[] args) {
        StudentDemo studentDemo = new StudentDemo();
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("\n请选择操作：1.添加学生 2.删除学生 3.输入成绩 4.输出成绩 5.退出");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    studentDemo.addStudents();
                    break;
                case 2:
                    studentDemo.delStudents();
                    break;
                case 3:
                    studentDemo.inputScore();
                    break;
                case 4:
                    studentDemo.outScore();
                    break;
                case 5:
                    System.exit(0);
                default:
                    System.out.println("请重新选择！");
            }
        }
    }
}