可以用java帮我写一个学生管理系统吗？能实现增删改查

当然可以！以下是一个简单的学生管理系统示例代码，实现了增删改查的功能：

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

public class StudentManagementSystem {
    static ArrayList<Student> students = new ArrayList<Student>();
    static Scanner scanner = new Scanner(System.in);

    public static void main(String[] args) {
        System.out.println("欢迎使用学生管理系统！");
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 添加学生");
            System.out.println("2. 删除学生");
            System.out.println("3. 修改学生信息");
            System.out.println("4. 查询学生信息");
            System.out.println("5. 退出系统");

            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addStudent();
                    break;
                case 2:
                    removeStudent();
                    break;
                case 3:
                    updateStudent();
                    break;
                case 4:
                    queryStudent();
                    break;
                case 5:
                    System.out.println("谢谢使用！");
                    System.exit(0);
            }
        }
    }

    public static void addStudent() {
        System.out.println("请输入学生信息：");
        System.out.print("姓名：");
        String name = scanner.next();
        System.out.print("学号：");
        String id = scanner.next();
        System.out.print("性别：");
        String gender = scanner.next();
        System.out.print("年龄：");
        int age = scanner.nextInt();
        System.out.print("成绩：");
        double score = scanner.nextDouble();
        Student student = new Student(name, id, gender, age, score);
        students.add(student);
        System.out.println("添加成功！");
    }

    public static void removeStudent() {
        System.out.print("请输入要删除的学生学号：");
        String id = scanner.next();
        for (int i = 0; i < students.size(); i++) {
            Student student = students.get(i);
            if (id.equals(student.getId())) {
                students.remove(i);
                System.out.println("删除成功！");
                return;
            }
        }
        System.out.println("该学生不存在！");
    }

    public static void updateStudent() {
        System.out.print("请输入要修改的学生学号：");
        String id = scanner.next();
        for (int i = 0; i < students.size(); i++) {
            Student student = students.get(i);
            if (id.equals(student.getId())) {
                System.out.println("请输入新的学生信息：");
                System.out.print("姓名：");
                String name = scanner.next();
                System.out.print("性别：");
                String gender = scanner.next();
                System.out.print("年龄：");
                int age = scanner.nextInt();
                System.out.print("成绩：");
                double score = scanner.nextDouble();
                student.setName(name);
                student.setGender(gender);
                student.setAge(age);
                student.setScore(score);
                System.out.println("修改成功！");
                return;
            }
        }
        System.out.println("该学生不存在！");
    }

    public static void queryStudent() {
        System.out.print("请输入要查询的学生学号：");
        String id = scanner.next();
        for (int i = 0; i < students.size(); i++) {
            Student student = students.get(i);
            if (id.equals(student.getId())) {
                System.out.println(student);
                return;
            }
        }
        System.out.println("该学生不存在！");
    }
}

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

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

    public String getName() {
        return name;
    }

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

    public String getId() {
        return id;
    }

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

    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;
    }

    public double getScore() {
        return score;
    }

    public void setScore(double score) {
        this.score = score;
    }

    @Override
    public String toString() {
        return "姓名：" + name + "\n学号：" + id + "\n性别：" + gender + "\n年龄：" + age + "\n成绩：" + score;
    }
}

在这个示例代码中，我们使用了一个静态的 ArrayList 对象来存储学生信息。在主函数中，我们使用了一个 while 循环来不断接受用户输入的操作，根据用户的选择来执行相应的函数。在每个函数中，我们使用 Scanner 对象来接受用户的输入，并根据输入来进行相应的操作，例如添加、删除、修改或查询学生信息。最后，我们使用 Student 类来封装学生信息，方便操作。