工作时间长了，经常用框架，感觉真的成了coding,建议有时间可以刷一下lettcode 时间一长就会忘，写了大半天，记录一下，理解后再写特别简单，链表逆序看了很多博客，写法各式各样，但是感觉解释的还是不清楚明了，所以在这又总结一下：

1.首先定义链表的结构 

定义的结构Node<T> 这样data 可以自定义的泛型，增加了灵活性：

public class Node<T> {public T data;public Node next; //可以理解为C语言的指针public Node(){}public Node(T data){this.data = data;}public T getData() {return data;}public void setData(T data) {this.data = data;}public Node getNext() {return next;}public void setNext(Node next) {this.next = next;}
}

 这里设计的 head 头指针数据默认为空也就是null;

 执行 temp =p ,p=q 执行流程如下：

 

 

执行 tmp =p;p=q;q=q->next 其中q=q->next 是类C/C++写法进行解释； 

 这里容易忽视：p.next=null 容易形成回环：

 q=q->next，在这里我理解为探针，查询是否已经到链表结尾了： 

 增删，逆序，具体代码如下：

import java.lang.reflect.Array;
import java.util.ArrayList;/*** @ClassName MyList* @Description* @Author qianxl* @Date 2019-09-07 17:34* @Version 1.0**/
public class MyList<T> {public Node head = new Node(-1);public Node current;/*** @param data* @description: 添加元素* @return: {@link Node}* @author qianxl* @date: 2019/9/7* @since 1.0*/public Node add(T data) {Node temp = head;Node before = new Node();do {before = temp;} while ((temp = temp.next) != null);
//注释部分是代码重构使用do while
//        before = temp;
//        while (temp != null) {
//            before = temp;
//            temp = temp.next;
//        }temp = new Node(data);before.next = temp;return head;}public Node remove(T values) {Node data = this.head;boolean flag = false;Node before;Node temp = data.next;do {before = data;if (values.equals(temp.data)) {flag = true;break;}} while ((temp = temp.next) != null);
//注释部分是代码重构使用do while
//        Node temp = data.next;
//        Node before =data;
//        while (temp != null) {
//            if (values.equals(temp.data)) {
//                flag = true;
//                break;
//            }
//            before = temp;
//            temp = temp.next;
//        }if (flag) {before.next = temp.next;}return head;}/*** @param* @description: 计算集合的长度* @return: {@link int}* @author qianxl* @date: 2019/9/7* @since 1.0*/public int size() {Node data = head;int count = 0;Node tmp;while (data != null) {data = data.next;count++;}return count - 1;//head 不存入数据}/*** @param index* @param value* @description: 指定位置插入值* @return: {@link Node}* @author qianxl* @date: 2019/9/8* @since 1.0*/public Node insert(int index, T value) {Node data = head.next; //去掉头指针if (index > this.size() || index < 1) {return head;}if (index == 1) {Node node = new Node(value);node.next = head.next;   //将新建的节点的指针指向，之前head 头结点指向的指针head.next = node;return head;}int count = 1;Node before = data; //do {if (index == count) {Node node = new Node(value);node.next = data;before.next = node; //指向新建的节点break;}count++;before = data;data = data.next;} while (data != null);
//注释部分是代码重构使用do while
//        Node before =data;
//        while (data != null) {
//            if (index == count) {
//                Node  node = new Node(value);
//                node.next=data;
//                before.next=node; //指向新建的节点
//                break;
//            }
//           count++;
//            before = data;
//            data = data.next;
//        }return head;}/*** @param* @description: 链表逆序* @return: {@link Node}* @author qianxl* @date: 2019/9/8* @since 1.0*/public Node reverse() {Node p,q=null;p = head.next; //指针 引用q = head.next.next;//q 指针可以理解为探针，在探是否到达链表末尾了Node tmp=null;p.setNext(null); //防止回环while (q != null) {tmp =p;p=q;q=q.next;   //q=q->next 起到探针的作用p.next=tmp;}head.next =p;return head;}public void print(Node node) {if (node.next == null) {return;}Node temp = node.next;while (temp != null) {System.out.print(temp.data+"  ");temp = temp.next;}System.out.println();}/*** @param array* @description: 将数组转换为list   head.next 理解为C语言指针，写链表操作一定要画图！* @return: {@link Node}* @author qianxl* @date: 2019/9/7* @since 1.0*/public Node arrayToList(T[] array) {Node data = head;for (int i = 0; i < array.length; i++) {Node node = new Node(array[i]);data.next = node;  //表情指向前驱data = node;  //表示}return head;}public static void main(String arg[]) {MyList<Object> list = new MyList<>();Node ddd = list.add("ddd");list.add("this is a list");list.add("fffff");list.remove("ddd");list.print(ddd);Node node = list.arrayToList(new String[]{"2","3","4"});list.print(node);// list.insert(1, "8");list.add("8");list.print(node);System.out.println();list.reverse();list.print(node);}
}

总结