java单链表基本操作的实现 [问题描述] 1、用顺序表方式实现在线通讯录的设计，可以对通讯录作插入、删除、显示、查找、修改等操作。（必做题） 2、用单链表方式实现在线通讯录的设计，可以对通讯录作插入、删除、显示、查找、修改等操作。（必做题）

单链表基本操作的实现：

1. 定义节点类Node：

public class Node {
    public String name;
    public String phoneNumber;
    public Node next;

    public Node(String name, String phoneNumber) {
        this.name = name;
        this.phoneNumber = phoneNumber;
        this.next = null;
    }
}

2. 定义单链表类LinkedList：

public class LinkedList {
    private Node head;

    public LinkedList() {
        head = null;
    }

    // 插入节点
    public void insert(String name, String phoneNumber) {
        Node newNode = new Node(name, phoneNumber);

        if (head == null) {
            head = newNode;
        } else {
            Node current = head;
            while (current.next != null) {
                current = current.next;
            }
            current.next = newNode;
        }
    }

    // 删除节点
    public void delete(String name) {
        if (head == null) {
            return;
        }

        if (head.name.equals(name)) {
            head = head.next;
            return;
        }

        Node current = head;
        while (current.next != null) {
            if (current.next.name.equals(name)) {
                current.next = current.next.next;
                return;
            }
            current = current.next;
        }
    }

    // 显示所有节点
    public void display() {
        Node current = head;
        while (current != null) {
            System.out.println(current.name + " " + current.phoneNumber);
            current = current.next;
        }
    }

    // 查找节点
    public Node find(String name) {
        Node current = head;
        while (current != null) {
            if (current.name.equals(name)) {
                return current;
            }
            current = current.next;
        }
        return null;
    }

    // 修改节点
    public void modify(String name, String newPhoneNumber) {
        Node node = find(name);
        if (node != null) {
            node.phoneNumber = newPhoneNumber;
        }
    }
}

3. 测试代码：

public class Test {
    public static void main(String[] args) {
        LinkedList list = new LinkedList();

        // 插入节点
        list.insert("张三", "123456");
        list.insert("李四", "234567");
        list.insert("王五", "345678");

        // 显示所有节点
        list.display();

        // 查找节点
        Node node = list.find("李四");
        if (node != null) {
            System.out.println(node.phoneNumber);
        }

        // 修改节点
        list.modify("张三", "111111");

        // 删除节点
        list.delete("王五");

        // 显示所有节点
        list.display();
    }
}