PS:双向链表（每个节点含有指向前一个节点的前驱与后一个节点的后继）public class DoublyLinkedList {	static class Node {		private Object data;		private Node prev;		public Node getPrev() {			return prev;		}		public void setPrev(Node prev) {			this.prev = prev;		}		private Node next;		public Node(Object value) {			this.data = value;		}		public Object getData() {			return data;		}		public void setData(Object data) {			this.data = data;		}		public Node getNext() {			return next;		}		public void setNext(Node next) {			this.next = next;		}		@Override		public String toString() {			return String.valueOf(data);		}	}	private Node head;// 头节点	public DoublyLinkedList() {		head = new Node(null);	}	// 双向链表表头插入节点	public void addFirst(Object value) {		Node node = new Node(value);		if (head.next == null) {			head.next = node;			node.prev = head;		} else {			node.prev = head;			node.next = head.next;			head.next.prev = node;			head.next = node;		}		// head=node;	}	// 删除表头	public void removeFirst() {		Node node = head.next;		if (node.next != null) {			node.next.prev = head;			head.next = node.next;		}	}	// 顺序打印链表	public void printList() {		Node node = head.next;		while (node != null) {			System.out.print(node.data + " ");			node = node.next;		}		System.out.println();	}	// 逆序打印链表	public void reversePrintList() {		Node node = head.next;		Node tail = null;		while (node.next != null) {			node = node.next;		}		tail = node;		// System.out.println(tail.data);		while (tail.prev != null) {			System.out.print(tail.data + " ");			tail = tail.prev;		}		System.out.println();	}	public static void main(String[] args) {		DoublyLinkedList linkedList = new DoublyLinkedList();		for (int i = 0; i < 10; i++) {			linkedList.addFirst(i);		}		System.out.println("顺序打印链表");		linkedList.printList();		System.out.println("逆序打印链表");		linkedList.reversePrintList();		System.out.println("依次删除头结点");		for (int i = 0; i < 10; i++) {			linkedList.removeFirst();			linkedList.printList();		}	}}