java链表反转代码怎么写

以下是Java中链表反转的示例代码：

public class ListNode {     int val;     ListNode next;      ListNode(int val) {         this.val = val;     } }  public class LinkedListReverse {     public static ListNode reverseList(ListNode head) {         ListNode prev = null;         ListNode current = head;         ListNode next = null;          while (current != null) {             next = current.next;             current.next = prev;             prev = current;             current = next;         }          return prev;     }      public static void main(String[] args) {         ListNode head = new ListNode(1);         head.next = new ListNode(2);         head.next.next = new ListNode(3);         head.next.next.next = new ListNode(4);         head.next.next.next.next = new ListNode(5);          ListNode reversedHead = reverseList(head);          System.out.print("Reversed List: ");         while (reversedHead != null) {             System.out.print(reversedHead.val + " ");             reversedHead = reversedHead.next;         }     } } 

运行以上代码，将会输出反转后的链表：

Reversed List: 5 4 3 2 1 

在反转链表的代码中，我们使用了三个指针prev、current和next。初始时，prev为null，current为头节点head，next为null。在每一次循环中，我们将current的next指针指向prev，然后依次向后移动prev、current和next指针。最终，prev指针将指向反转后的链表头节点，我们将其返回即可。