如何在Java中反轉單連結串列？

package test;

/**
 * Java Program to reverse a singly list without using recursion.
 */
public class LinkedListProblem {

  public static void main(String[] args) {

    // creating a singly linked list
    SinglyLinkedList.Node head = new SinglyLinkedList.Node(1);
    SinglyLinkedList linkedlist = new SinglyLinkedList(head);

    // adding node into singly linked list
    linkedlist.add(new SinglyLinkedList.Node(2));
    linkedlist.add(new SinglyLinkedList.Node(3));
    // printing a singly linked list
    linkedlist.print();

    // reversing the singly linked list
    linkedlist.reverse();

    // printing the singly linked list again
    linkedlist.print();

  }

}
/**
 * A class to represent singly list in Java
 * 
 * @author WINDOWS 8
 *
 */
class SinglyLinkedList {

  static class Node {

    private int data;
    private Node next;

    public Node(int data) {
      this.data = data;
    }

    public int data() {
      return data;
    }

    public Node next() {
      return next;
    }
  }

  private Node head;

  public SinglyLinkedList(Node head) {
    this.head = head;
  }

  /**
   * Java method to add an element to linked list
   * @param node
   */
  public void add(Node node) {
    Node current = head;
    while (current != null) {
      if (current.next == null) {
        current.next = node;
        break;
      }
      current = current.next;
    }
  }

  /**
   * Java method to print a singly linked list
   */
  public void print() {
    Node node = head;
    while (node != null) {
      System.out.print(node.data() + " ");
      node = node.next();
    }
    System.out.println("");
  }

  /**
   * Java method to reverse a linked list without recursion
   */
  public void reverse() {
    Node pointer = head;
    Node previous = null, current = null;

    while (pointer != null) {
      current = pointer;
      pointer = pointer.next;

      // reverse the link
      current.next = previous;
      previous = current;
      head = current;
    }

  }
}
Output
1 2 3 
3 2 1