Java 创建链表，增删改查

package linkedList;

public class Node {
    int data;
    Node next;

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

package linkedList;

public class LinkedList {
    private Node first; //指向第一个节点(默认为null)
    private Node last;  //指向第二个节点

    //判断链表是否为空
    public boolean isEmpty(){
        return (first==null);
    }

    //打印链表元素
    public void print(){
        Node current = first;   //定义游标指向头节点
        while (current != null){
            System.out.print(current.data + "   ");
            current = current.next;
        }
        System.out.println();
    }

    public void insert(int data){
        Node newNode = new Node(data); //封装数据
        if(this.isEmpty()){     //若当前是空链表
            first = newNode;    //头和尾都指向该节点
            last = newNode;
        }else{      //该链表非空
            last.next = newNode;
            last = newNode;
        }
    }

    public static void test(){
        LinkedList linkedList = new LinkedList();

        System.out.println("输入5个数据：");
        linkedList.insert(10);
        linkedList.insert(20);
        linkedList.insert(30);
        linkedList.insert(40);
        linkedList.insert(50);

        System.out.println("打印链表：");
        linkedList.print();
    }
}

import linkedList.LinkedList;

public class Test {
    public static void main(String[] args) {
        LinkedList.test();
    }
}