1. 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 "姓名：" + name + "，性别：" + gender + "，年龄：" + age;
    }
}

Student类：

public class Student extends Person {
    private int studentNumber;
    private String className;
    private int englishScore;
    private int mathScore;
    private int javaScore;

    public Student() {}

    public Student(String name, String gender, int age, int studentNumber, String className, int englishScore, int mathScore, int javaScore) {
        super(name, gender, age);
        this.studentNumber = studentNumber;
        this.className = className;
        this.englishScore = englishScore;
        this.mathScore = mathScore;
        this.javaScore = javaScore;
    }

    public int getStudentNumber() {
        return studentNumber;
    }

    public void setStudentNumber(int studentNumber) {
        this.studentNumber = studentNumber;
    }

    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public int getEnglishScore() {
        return englishScore;
    }

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

    public int getMathScore() {
        return mathScore;
    }

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

    public int getJavaScore() {
        return javaScore;
    }

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

    @Override
    public String toString() {
        return super.toString() + "，学号：" + studentNumber + "，班级：" + className + "，英语成绩：" + englishScore + "，数学成绩：" + mathScore + "，java成绩：" + javaScore;
    }
}

StudentDemo类：

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

public class StudentDemo {

    private List<Student> students = new ArrayList<>();

    public void addStudents() {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入学生的基本信息：");
        System.out.print("姓名：");
        String name = input.next();
        System.out.print("性别：");
        String gender = input.next();
        System.out.print("年龄：");
        int age = input.nextInt();
        System.out.print("学号：");
        int studentNumber = input.nextInt();
        System.out.print("班级：");
        String className = input.next();
        Student student = new Student(name, gender, age, studentNumber, className, 0, 0, 0);
        students.add(student);
        System.out.println("添加成功！学生信息为：");
        System.out.println(student);
    }

    public void delStudents() {
        Scanner input = new Scanner(System.in);
        System.out.print("请输入要删除学生的学号：");
        int studentNumber = input.nextInt();
        Iterator<Student> it = students.iterator();
        while (it.hasNext()) {
            Student student = it.next();
            if (student.getStudentNumber() == studentNumber) {
                it.remove();
                System.out.println("删除成功！删除学生信息为：");
                System.out.println(student);
                return;
            }
        }
        System.out.println("删除失败！学号" + studentNumber + "的学生不存在！");
    }

    public void inputScore() {
        Scanner input = new Scanner(System.in);
        for (Student student : students) {
            System.out.println("为学生" + student.getName() + "输入英语成绩：");
            int englishScore = input.nextInt();
            student.setEnglishScore(englishScore);
            System.out.println("为学生" + student.getName() + "输入数学成绩：");
            int mathScore = input.nextInt();
            student.setMathScore(mathScore);
            System.out.println("为学生" + student.getName() + "输入java成绩：");
            int javaScore = input.nextInt();
            student.setJavaScore(javaScore);
        }
    }

    public void outScore() {
        for (Student student : students) {
            int averageScore = (student.getEnglishScore() + student.getMathScore() + student.getJavaScore()) / 3;
            System.out.println(student.getName() + " " + student.getStudentNumber() + " " + student.getClassName() + " " + student.getEnglishScore() + " " + student.getMathScore() + " " + student.getJavaScore() + " " + averageScore);
        }
    }

    public static void main(String[] args) {
        StudentDemo test = new StudentDemo();
        while (true) {
            System.out.println("请选择要进行的操作：");
            System.out.println("1. 添加学生");
            System.out.println("2. 删除学生");
            System.out.println("3. 输入成绩");
            System.out.println("4. 输出成绩");
            Scanner input = new Scanner(System.in);
            int choice = input.nextInt();
            switch (choice) {
                case 1:
                    test.addStudents();
                    break;
                case 2:
                    test.delStudents();
                    break;
                case 3:
                    test.inputScore();
                    break;
                case 4:
                    test.outScore();
                    break;
                default:
                    System.out.println("无效的操作！");
                    break;
            }
        }
    }

}