java实现不带头结点的单链表

以下是Java实现不带头结点的单链表的代码：

public class SinglyLinkedList {
    private Node head;

    private class Node {
        private int data;
        private Node next;

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

    public SinglyLinkedList() {
        this.head = null;
    }

    public boolean isEmpty() {
        return head == null;
    }

    public void insertFirst(int data) {
        Node newNode = new Node(data);
        newNode.next = head;
        head = newNode;
    }

    public void insertLast(int data) {
        Node newNode = new Node(data);
        if (isEmpty()) {
            head = newNode;
            return;
        }
        Node current = head;
        while (current.next != null) {
            current = current.next;
        }
        current.next = newNode;
    }

    public Node deleteFirst() {
        if (isEmpty()) {
            return null;
        }
        Node temp = head;
        head = head.next;
        return temp;
    }

    public void displayList() {
        Node current = head;
        while (current != null) {
            System.out.print(current.data + " ");
            current = current.next;
        }
        System.out.println();
    }
}

这里使用了内部类`Node`来表示链表中的节点，其中`data`表示节点存储的数据，`next`表示指向下一个节点的引用。`head`表示链表的头节点，初始值为`null`。链表的操作包括：判断链表是否为空、在链表头部插入节点、在链表尾部插入节点、删除链表头部节点、打印整个链表。