Java实现双向链表

package com.company;

/**
 * @author:抱着鱼睡觉的喵喵
 * @date:2021/2/9
 * @description:
 */
public class DoubleLinkedListDemo {

    public static void main(String[] args) {
        Node2 node1 = new Node2(2, 100, "李四");
        Node2 node2 = new Node2(3, 99, "张三");
        DoubleLinkedList doubleLinkedList = new DoubleLinkedList();
        doubleLinkedList.add(node1);
        doubleLinkedList.add(node2);
        doubleLinkedList.list();
        Node2 node3 = new Node2(1, 98, "zms");
        doubleLinkedList.insert(node3);
        System.out.println("插入1号数据之后:");
        doubleLinkedList.list();
        doubleLinkedList.delete(3);
        System.out.println("删除3号数据之后:");
        doubleLinkedList.list();
        Node2 node4 = new Node2(2, 53, "zsh");
        doubleLinkedList.modify(node4);
        System.out.println("修改2号数据之后:");
        doubleLinkedList.list();
    }
}

class Node2 {
    public Node2 next;
    public Node2 pre;
    public int sno;
    public int score;
    public String data;


    public Node2() {
    }

    public Node2(int Sno, int NScore, String Data) {
        this.sno = Sno;
        this.score = NScore;
        this.data = Data;
    }

    @Override
    public String toString() {
        return "Node2{" +
                "sno=" + sno +
                ", score=" + score +
                ", data='" + data + '\'' +
                '}';
    }
}

class DoubleLinkedList {

    private Node2 head = new Node2(0, 0, "");

    public Node2 getHead() {
        return head;
    }

    public void list() {
        Node2 temp = head.next;
        if (temp == null) {
            System.out.println("LinkedList is empty!");
        } else {
            while (temp != null) {
                System.out.println(temp);
                System.out.println();
                temp = temp.next;
            }
        }
    }

    public void add(Node2 node) {
        Node2 temp = head;
        while (true) {
            if (temp.next == null) {
                break;
            }
            temp = temp.next;
        }
        temp.next = node;
        node.pre = temp;
    }

    public void insert(Node2 node) {
        Node2 temp = head;
        boolean flag = false;
        while (true) {
            if (temp.next == null) {
                break;
            }
            if (temp.next.sno > node.sno) {
                break;
            }
            if (temp.next.sno == node.sno) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag == true) {
            System.out.println("the sno:" + node.sno + "already exists！");
            return;
        } else {
            node.next = temp.next;
            temp.next.pre = node;
            temp.next = node;
            node.pre = temp;
        }

    }

    public void delete(int Sno) {

        if (head.next == null) {
            System.out.println("LinkedList is empty!");
            return;
        }
        Node2 temp = head.next;
        boolean flag = false;
        while (true) {
            if (temp == null) {
                break;
            }
            if (temp.sno == Sno) {
                flag = true;
                break;
            }
            temp = temp.next;
        }
        if (flag == false) {
            System.out.println("查无此人:"+Sno+"，无法删除!");
        } else {
           temp.pre.next = temp.next;
           if (temp.next != null){
               temp.next.pre = temp.pre;
           }
        }
    }

    public void modify(Node2 node) {
        if (this.head == null) {
            System.out.println("LinkedList is empty！");
            return;
        }
        Node2 temp = head;
        while(true) {
            if (temp.next == null) {
                System.out.println("查无此人:"+node.sno+",无法修改:");
                break;
            }
            if (temp.next.sno == node.sno) {
                temp.next.score = node.score;
                temp.next.data = node.data;
                break;
            }
            temp = temp.next;
        }
    }

}