1、代码

package LinkList;public class Linklist {//定义节点，内部类只为其外部类使用//要创建嵌套类的对象，并不需要其外围类的对象，直接使用.nextstatic class ListNode{int val;//数据域ListNode next;//指针，指向下一个结点的位置(java里面是引用数据类型——地址)public ListNode(int val){this.val = val;}}//队首指针和队尾指针ListNode head;ListNode tail;int size;//链表长度//定义链表（初始化链表）public Linklist(){head = null;tail = null;size = 0;}public static void main(String[] args) {//初始化链表Linklist newList = new Linklist();newList.appendIntail(5);newList.appendIntail(7);newList.appendIntail(4);newList.appendIntail(2);newList.printList();newList.appendInHead(30);newList.appendInHead(27);newList.insert(3,9);newList.printList();newList.deleteNode(9);newList.printList();newList.findInNumber(4);newList.findInNumber(1);newList.findInIndex(9);newList.update(11,2);newList.printList();}//增加新元素至表尾public void appendIntail(int number){//创建一个值为number的结点ListNode newNode = new ListNode(number);//链表为空时，申请的结点就是第一个结点也是表尾结点if(tail == null){tail = newNode;head =newNode;}else {//链表不空直接加入表尾tail.next = newNode;tail = newNode;}size++;System.out.println("值为" + number +"的结点成功加入链表！");}//头插法建立单链表public void appendInHead(int number){ListNode newNode = new ListNode(number);if(tail == null){//初试链表为空head = newNode;tail = newNode;System.out.println("头插法成功！");}else {//链表不空，放在首节点之前newNode.next = head;head = newNode;System.out.println("头插法成功！");}}//在position插入值为number的结点public void insert(int position,int number){if(position >size){//插入位置不合法return;}ListNode newNode = new ListNode(number);if(position == 0){//在首节点之前插入newNode.next=head;head = newNode;if(tail == null){//说明新结点是该链表第一个插入的结点tail = newNode;}size++;System.out.println("插入成功！");} else if (position == size){//插入位置在最后一个的后一个，直接加载末尾this.appendIntail(number);System.out.println("插入成功！");}else {//找到要插入位置的前一个位置//从头结点开始遍历，直到找到position-1的位置ListNode pre = head;for(int i = 0;i < position-1;i++){pre = pre.next;}//插入newNode.next=pre.next;pre.next = newNode;size++;System.out.println("插入成功！");}}//打印链表public void printList(){System.out.print("链表：[");ListNode cur = head;while (cur != null){if(cur.next == null){System.out.println(cur.val +"]");cur = cur.next;return;}System.out.print(cur.val + ",");cur = cur.next;}System.out.println(" ");}//按值删除public void deleteNode(int number){//第一个节点是要删除的结点的情况下,直接删除if(head !=null && head.val == number){head = head.next;size--;if(size == 0){//表为空的情况下tail = head;}System.out.println("删除成功，成功删除值为" + number + "的结点");}else {//否则就遍历链表找到值为number的结点的前一个结点ListNode pre = head;ListNode cur = head;//遍历while (cur != null){if(cur.val == number){//要删除的结点是表尾结点，修改tailif (cur == tail){pre.next = null;tail = pre;size--;System.out.println("删除成功，成功删除值为" + number + "的结点");return;}else {//删除的不是表尾结点，正常删除pre.next = cur.next;size--;System.out.println("删除成功，成功删除值为" + number + "的结点");return;}}else {//不是要删除的结点，继续向后滑动遍历pre = cur;cur = cur.next;}}//while结束后还没成功删除，说明没有值为number的结点System.out.println("删除失败，没有该结点");return;}}//按值查找public void findInNumber(int number){ListNode p = head;while (p != null){if(p.val == number){System.out.println("查找成功！");return;}else {p = p.next;}}System.out.println("不存在该数,查找失败！");return;}//按位查找public void findInIndex(int index){if(index > size){System.out.println("查找失败，位置非法！");}else {ListNode cur = head;int i = 0;while (i < index){cur = cur.next;i++;}System.out.println("查找成功，查找到的数值为：" + cur.val);}}//更新值为oldvalue的结点为newValue,并返回更新结点的位置public int update(int oldValue,int newValue){int i = 1;ListNode cur = head;while (cur != null){if(cur.val == oldValue){cur.val = newValue;System.out.println("更新成功！");return i;}else {i++;cur = cur.next;}}System.out.println("更新失败！不存在值为" + oldValue + "的结点");return -1;}}

2、结果