如何使用Java代码实现小型学生信息管理程序（不用实现界面），功能包括基本的添加学生、删除、修改和查询学生信息等操作，要求用链表实现：用户可选择五个操作之一：添加学生、修改学生、删除学生、查询学生、显示学生链表的当前状态和退出程序，测试上述所有功能。

好的，以下是一份使用Java代码实现小型学生信息管理程序的参考：

import java.util.Scanner;

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

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

    public String getName() {
        return name;
    }

    public int getId() {
        return id;
    }

    public int getAge() {
        return age;
    }

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

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

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

    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", id=" + id +
                ", age=" + age +
                '}';
    }
}

class Node {
    private Student data;
    private Node next;

    public Node(Student data) {
        this.data = data;
        this.next = null;
    }

    public Student getData() {
        return data;
    }

    public void setData(Student data) {
        this.data = data;
    }

    public Node getNext() {
        return next;
    }

    public void setNext(Node next) {
        this.next = next;
    }
}

class LinkedList {
    private Node head;

    public LinkedList() {
        head = null;
    }

    public void add(Student data) {
        Node node = new Node(data);
        if (head == null) {
            head = node;
        } else {
            Node current = head;
            while (current.getNext() != null) {
                current = current.getNext();
            }
            current.setNext(node);
        }
    }

    public void delete(int id) {
        if (head != null) {
            if (head.getData().getId() == id) {
                head = head.getNext();
            } else {
                Node current = head;
                while (current.getNext() != null && current.getNext().getData().getId() != id) {
                    current = current.getNext();
                }
                if (current.getNext() != null) {
                    current.setNext(current.getNext().getNext());
                }
            }
        }
    }

    public void update(Student data) {
        if (head != null) {
            Node current = head;
            while (current != null && current.getData().getId() != data.getId()) {
                current = current.getNext();
            }
            if (current != null) {
                current.setData(data);
            }
        }
    }

    public Student search(int id) {
        Node current = head;
        while (current != null && current.getData().getId() != id) {
            current = current.getNext();
        }
        if (current != null) {
            return current.getData();
        } else {
            return null;
        }
    }

    public void display() {
        Node current = head;
        while (current != null) {
            System.out.println(current.getData().toString());
            current = current.getNext();
        }
    }
}

public class StudentManagement {
    public static void main(String[] args) {
        LinkedList list = new LinkedList();
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.println("请选择操作：");
            System.out.println("1. 添加学生");
            System.out.println("2. 修改学生");
            System.out.println("3. 删除学生");
            System.out.println("4. 查询学生");
            System.out.println("5. 显示学生链表的当前状态");
            System.out.println("6. 退出程序");
            int option = scanner.nextInt();
            switch (option) {
                case 1:
                    System.out.println("请输入学生姓名：");
                    String name = scanner.next();
                    System.out.println("请输入学生学号：");
                    int id = scanner.nextInt();
                    System.out.println("请输入学生年龄：");
                    int age = scanner.nextInt();
                    Student student = new Student(name, id, age);
                    list.add(student);
                    System.out.println("添加成功！");
                    break;
                case 2:
                    System.out.println("请输入要修改的学生学号：");
                    int updateId = scanner.nextInt();
                    Student updateStudent = list.search(updateId);
                    if (updateStudent != null) {
                        System.out.println("请输入要修改的学生姓名：");
                        String updateName = scanner.next();
                        System.out.println("请输入要修改的学生年龄：");
                        int updateAge = scanner.nextInt();
                        Student newStudent = new Student(updateName, updateId, updateAge);
                        list.update(newStudent);
                        System.out.println("修改成功！");
                    } else {
                        System.out.println("未找到该学生！");
                    }
                    break;
                case 3:
                    System.out.println("请输入要删除的学生学号：");
                    int deleteId = scanner.nextInt();
                    list.delete(deleteId);
                    System.out.println("删除成功！");
                    break;
                case 4:
                    System.out.println("请输入要查询的学生学号：");
                    int searchId = scanner.nextInt();
                    Student searchStudent = list.search(searchId);
                    if (searchStudent != null) {
                        System.out.println(searchStudent.toString());
                    } else {
                        System.out.println("未找到该学生！");
                    }
                    break;
                case 5:
                    list.display();
                    break;
                case 6:
                    System.out.println("程序已退出！");
                    System.exit(0);
                    break;
                default:
                    System.out.println("输入有误，请重新输入！");
                    break;
            }
        }
    }
}

在上述代码中，我们首先定义了学生类 `Student` 和节点类 `Node`，然后定义了链表类 `LinkedList`，其中包括添加学生、删除学生、修改学生、查询学生、显示学生链表的当前状态等操作。最后，在 `main` 方法中通过 `Scanner` 类实现了基本的用户交互和测试。

希望能对你有所帮助！