用java写学生管理系统

好的，我可以为您提供一个简单的学生管理系统的Java代码框架，代码如下：

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

public class StudentManagementSystem {
    private ArrayList<Student> students = new ArrayList<>();

    // 添加学生信息
    public void addStudent() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生姓名：");
        String name = scanner.next();
        System.out.println("请输入学生年龄：");
        int age = scanner.nextInt();
        System.out.println("请输入学生性别：");
        String gender = scanner.next();
        System.out.println("请输入学生学号：");
        String id = scanner.next();
        students.add(new Student(name, age, gender, id));
        System.out.println("添加学生信息成功！");
    }

    // 查询学生信息
    public void queryStudent() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生学号：");
        String id = scanner.next();
        for (Student student : students) {
            if (student.getId().equals(id)) {
                System.out.println(student);
                return;
            }
        }
        System.out.println("未找到该学生信息！");
    }

    // 删除学生信息
    public void deleteStudent() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生学号：");
        String id = scanner.next();
        for (Student student : students) {
            if (student.getId().equals(id)) {
                students.remove(student);
                System.out.println("删除学生信息成功！");
                return;
            }
        }
        System.out.println("未找到该学生信息！");
    }

    // 修改学生信息
    public void modifyStudent() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入学生学号：");
        String id = scanner.next();
        for (Student student : students) {
            if (student.getId().equals(id)) {
                System.out.println("请输入学生姓名：");
                String name = scanner.next();
                System.out.println("请输入学生年龄：");
                int age = scanner.nextInt();
                System.out.println("请输入学生性别：");
                String gender = scanner.next();
                student.setName(name);
                student.setAge(age);
                student.setGender(gender);
                System.out.println("修改学生信息成功！");
                return;
            }
        }
        System.out.println("未找到该学生信息！");
    }

    // 输出所有学生信息
    public void displayAllStudents() {
        for (Student student : students) {
            System.out.println(student);
        }
    }
}

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

    public int getAge() {
        return age;
    }

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

    public String getGender() {
        return gender;
    }

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

    public String getId() {
        return id;
    }

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

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

以上就是一个简单的学生管理系统的Java代码框架，您可以根据自己的需求进行修改和完善。