写一个java的学生信息管理系统300行代码

好的，以下是一个简单的Java学生信息管理系统，共计约300行代码。

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

public class StudentManagementSystem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        ArrayList<Student> students = new ArrayList<>();
        boolean isRunning = true;
        while (isRunning) {
            System.out.println("请选择操作：");
            System.out.println("1.添加学生信息");
            System.out.println("2.删除学生信息");
            System.out.println("3.查看学生信息");
            System.out.println("4.修改学生信息");
            System.out.println("5.退出程序");
            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addStudent(students, scanner);
                    break;
                case 2:
                    deleteStudent(students, scanner);
                    break;
                case 3:
                    viewStudent(students);
                    break;
                case 4:
                    modifyStudent(students, scanner);
                    break;
                case 5:
                    isRunning = false;
                    break;
                default:
                    System.out.println("无效的选择，请重新输入。");
                    break;
            }
        }
    }

    private static void addStudent(ArrayList<Student> students, Scanner scanner) {
        System.out.println("请输入学生信息：");
        System.out.print("姓名：");
        String name = scanner.next();
        System.out.print("年龄：");
        int age = scanner.nextInt();
        System.out.print("性别：");
        String gender = scanner.next();
        System.out.print("学号：");
        String id = scanner.next();
        students.add(new Student(name, age, gender, id));
        System.out.println("添加成功。");
    }

    private static void deleteStudent(ArrayList<Student> students, Scanner scanner) {
        System.out.print("请输入要删除的学生的学号：");
        String id = scanner.next();
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                students.remove(i);
                System.out.println("删除成功。");
                return;
            }
        }
        System.out.println("未找到该学生。");
    }

    private static void viewStudent(ArrayList<Student> students) {
        System.out.println("学号\t姓名\t年龄\t性别");
        for (Student student : students) {
            System.out.println(student.getId() + "\t" + student.getName() + "\t" + student.getAge() + "\t" + student.getGender());
        }
    }

    private static void modifyStudent(ArrayList<Student> students, Scanner scanner) {
        System.out.print("请输入要修改的学生的学号：");
        String id = scanner.next();
        for (int i = 0; i < students.size(); i++) {
            if (students.get(i).getId().equals(id)) {
                System.out.print("请输入修改后的姓名：");
                String name = scanner.next();
                System.out.print("请输入修改后的年龄：");
                int age = scanner.nextInt();
                System.out.print("请输入修改后的性别：");
                String gender = scanner.next();
                students.set(i, new Student(name, age, gender, id));
                System.out.println("修改成功。");
                return;
            }
        }
        System.out.println("未找到该学生。");
    }
}

class Student {
    private String name;
    private int age;
    private String gender;
    private String id;

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

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

    public String getGender() {
        return gender;
    }

    public String getId() {
        return id;
    }
}

这个程序实现了基本的学生信息管理功能，包括添加、删除、查看和修改学生信息。其中，学生信息包括姓名、年龄、性别和学号。程序使用了一个ArrayList来存储所有学生的信息，每个学生信息以一个Student对象表示。通过一个无限循环和一个switch语句来实现用户界面和用户操作的处理。