手写链表实现

public class LinkList {
    public static void main(String[] args) {
        int[] a = {1, 2, 3, 4, 5, 6};
        Node head = initLinkedList(a);
        System.out.println("初始化成功");
        System.out.println("获取长度："+getLength(head));
        System.out.println("转为字符串输出："+toString(head));
        head = insertNode(head,new Node(0),1);
        System.out.println("头插："+toString(head));
        head = insertNode(head,new Node(7),7);
        System.out.println("尾插："+toString(head));
        head = deleteNode(head,1);
        System.out.println("头删："+toString(head));
        head = deleteNode(head,6);
        System.out.println("尾删："+toString(head));
    }

    /**
     * 插入节点
     * @param head 头结点
     * @param insertNode 待插入结点
     * @param position 插入位置
     * @return 插入后的链表头结点
     */
    public static Node insertNode(Node head,Node insertNode,int position){
        //判空
        if(head==null){
            return insertNode;
        }
        //判断是否越界
        int size = getLength(head);
        if(position>size+1||position<1){
            System.out.println("越界异常");
            return head;
        }
        //头插
        if(position==1){
            insertNode.next = head;
            head = insertNode;
            return head;
        }
        //中间及尾插
        Node midNode = head;
        int count = 0;
        while (count < position-1){
            midNode = midNode.next;
            count++;
        }
        insertNode.next = midNode.next;
        midNode.next = insertNode;
        return head;
    }

    /**
     * 删除结点
     * @param head 头结点
     * @param position 删除的位置
     * @return 输出的链表
     */
    public static Node deleteNode(Node head,int position){
        //判空
        if(head==null){
            System.out.println("链表为空，无法删除");
            return null;
        }
        //判断参数是否越界
        int size = getLength(head);
        if(position>size||position<=0){
            System.out.println("位置参数输入有误");
            return head;
        }
        if(position==1){
            return head.next;
        }
        Node midNode = head;
        int count = 1;
        while (count<position){
            count++;
            midNode = midNode.next;
        }
        midNode.next = midNode.next.next;
        return  head;
    }
    /**
     * 输出链表
     * @param head 头结点
     * @return 输出的链表
     */
    public static String toString(Node head){
        Node node = head;
        StringBuilder str = new StringBuilder();
        while (node!=null){
            str.append(node.val).append(" ");
            node = node.next;
        }
        return str.toString();
    }
    /**
     * 获取链表长度
     * @param head 头结点
     * @return 链表长度
     */
    public static int getLength(Node head){
        int length = 0;
        Node node = head;
        while (node!=null){
            length++;
            node = node.next;
        }
        return length;
    }
    /**
     * 链表初始化
     * @param array
     * @return
     */
    public static Node initLinkedList(int[] array){
        Node head = null,cur = null;
        for (int i = 0; i < array.length; i++) {
            Node newNode = new Node(array[i]);
            if(i==0){
                head = newNode;
                cur = head;
            }else {
                cur.next = newNode;
                cur = newNode;
            }
        }
        return head;
    }
    static class Node{
        public int val;
        public Node next;

        Node(int x) {
            val = x;
            next = null;
        }
    }
}