初学者如何用Java写一个学生管理系统

public class Student {
    private String id;
    private String name;
    private int age;
<pre class='brush:java;toolbar:false;'>public Student() {}

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

// Getter 和 Setter 方法
public String getId() {
    return id;
}

public void setId(String id) {
    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;
}

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

import java.util.ArrayList;
import java.util.Scanner;
<p>public class StudentManager {
public static void main(String[] args) {
ArrayList<Student> list = new ArrayList<>();
Scanner sc = new Scanner(System.in);
while (true) {
System.out.println("\n--- 学生管理系统 ---");
System.out.println("1 添加学生");
System.out.println("2 查看所有学生");
System.out.println("3 查询学生");
System.out.println("4 修改学生");
System.out.println("5 删除学生");
System.out.println("6 退出");
System.out.print("请选择操作：");</p><pre class='brush:java;toolbar:false;'>        int choice = sc.nextInt();
        sc.nextLine(); // 消费换行符

        switch (choice) {
            case 1:
                addStudent(list, sc);
                break;
            case 2:
                showStudents(list);
                break;
            case 3:
                findStudent(list, sc);
                break;
            case 4:
                updateStudent(list, sc);
                break;
            case 5:
                deleteStudent(list, sc);
                break;
            case 6:
                System.out.println("再见！");
                sc.close();
                return;
            default:
                System.out.println("输入无效，请重新选择。");
        }
    }
}

public static void addStudent(ArrayList<Student> list, Scanner sc) {
    System.out.print("请输入学号：");
    String id = sc.nextLine();
    if (findIndexById(list, id) != -1) {
        System.out.println("该学号已存在！");
        return;
    }
    System.out.print("请输入姓名：");
    String name = sc.nextLine();
    System.out.print("请输入年龄：");
    int age = sc.nextInt();
    sc.nextLine();

    Student s = new Student(id, name, age);
    list.add(s);
    System.out.println("添加成功！");
}

public static void showStudents(ArrayList<Student> list) {
    if (list.isEmpty()) {
        System.out.println("暂无学生信息。");
        return;
    }
    for (Student s : list) {
        System.out.println(s);
    }
}

public static void findStudent(ArrayList<Student> list, Scanner sc) {
    System.out.print("请输入要查询的学号：");
    String id = sc.nextLine();
    int index = findIndexById(list, id);
    if (index == -1) {
        System.out.println("未找到该学生。");
    } else {
        System.out.println("找到学生：" + list.get(index));
    }
}

public static void updateStudent(ArrayList<Student> list, Scanner sc) {
    System.out.print("请输入要修改的学生学号：");
    String id = sc.nextLine();
    int index = findIndexById(list, id);
    if (index == -1) {
        System.out.println("未找到该学生。");
        return;
    }
    System.out.print("请输入新姓名：");
    String name = sc.nextLine();
    System.out.print("请输入新年龄：");
    int age = sc.nextInt();
    sc.nextLine();

    Student s = list.get(index);
    s.setName(name);
    s.setAge(age);
    System.out.println("修改成功！");
}

public static void deleteStudent(ArrayList<Student> list, Scanner sc) {
    System.out.print("请输入要删除的学生学号：");
    String id = sc.nextLine();
    int index = findIndexById(list, id);
    if (index == -1) {
        System.out.println("未找到该学生。");
        return;
    }
    list.remove(index);
    System.out.println("删除成功！");
}

// 根据学号查找索引
public static int findIndexById(ArrayList<Student> list, String id) {
    for (int i = 0; i < list.size(); i++) {
        if (list.get(i).getId().equals(id)) {
            return i;
        }
    }
    return -1;
}