Java从头到尾打印链表

/**
 * @author kegekeqi
 * @version 1.0
 * @date 2021-12-5 14:18
 */
public class ListNode {
  int val;
  ListNode next;

  public int getVal() {
    return val;
  }

  public void setVal(int val) {
    this.val = val;
  }

  public ListNode getNext() {
    return next;
  }

  public void setNext(ListNode next) {
    this.next = next;
  }

  @Override
  public String toString() {
    return "ListNode{" +
        "val=" + val +
        ", next=" + next +
        '}';
  }
}

import java.util.ArrayList;
import java.util.LinkedList;

/**
 * @author kegekeqi
 * @version 1.0
 * @date 2021-12-5 14:16
 */
public class ChapterTwo {
  //链表从头到尾输出来
  public LinkedList<Integer> printByTail(ListNode listNode) {
    LinkedList<Integer> result = new LinkedList<>();
    if (null == listNode) {
      return result;
    }
    LinkedList<Integer> stack = new LinkedList<>();
    while (null != listNode) {
      stack.add(listNode.val);
      listNode = listNode.next;
    }
    for (int i = stack.size() - 1; i >= 0; i--) {
      result.add(stack.get(i));
    }
    return result;
  }

  public static void main(String[] args) {
    ChapterTwo chapterTwo = new ChapterTwo();
    ListNode listNode = new ListNode();
    listNode.setVal(1);
    ListNode listNode1 = new ListNode();
    listNode1.setVal(3);
    listNode.setNext(listNode1);
    ListNode listNode2 = new ListNode();
    listNode2.setVal(89);
    listNode1.setNext(listNode2);
    ListNode listNode3 = new ListNode();
    listNode3.setVal(9);
    listNode2.setNext(listNode3);
    ListNode listNode4 = new ListNode();
    listNode4.setVal(34);
    listNode3.setNext(listNode4);
    System.out.println(listNode);
    LinkedList<Integer> integers = chapterTwo.printByTail(listNode);
    System.out.println("===================");
    System.out.println(integers);
  }

}