在二叉树中找到一个节点的后继节点

//在二叉树中找到一个节点的后继节点
public class getNextNode{
	//节点的定义
	public static class Node{
		public int value;
		public Node left;
		public Node right;
		public Node parent;

		public Node(int data)
		{
			this.value=data;
		}
	}
    //给定一个节点获得其后继节点
	public static Node getNextNode(Node node)
	{
		//
		if(node==null)
		{
			return node;
		}
		//如果有子树,那么后继节点就是右子树上最左边的节点
		if(node.right!=null)
		{
			return getLeftMost(node.right);
		}//节点上移寻找父节点
		else{

			Node parent=node.parent;
			while(parent!=null&&parent.left!=node)
			{
				node=parent;
				parent=node.parent;
			}
			return parent;
		}

	}

	public static Node getLeftMost(Node node)
	{
		if(node==null){
			return node;
		}
		while(node.left!=null)
		{
			node=node.left;
		}
		return node;
	}
  
	public static  void main(String[]args)
	{
        /**构造的二叉树
                 6
             3         9
          1    4    8     10

           2    5  7
       */ 
     	Node head = new Node(6);
		head.parent = null;
		head.left = new Node(3);
		head.left.parent = head;
		head.left.left = new Node(1);
		head.left.left.parent = head.left;
		head.left.left.right = new Node(2);
		head.left.left.right.parent = head.left.left;
		head.left.right = new Node(4);
		head.left.right.parent = head.left;
		head.left.right.right = new Node(5);
		head.left.right.right.parent = head.left.right;
		head.right = new Node(9);
		head.right.parent = head;
		head.right.left = new Node(8);
		head.right.left.parent = head.right;
		head.right.left.left = new Node(7);
		head.right.left.left.parent = head.right.left;
		head.right.right = new Node(10);
		head.right.right.parent = head.right;

		Node test = head.left.left;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.left.left.right;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.left;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.left.right;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.left.right.right;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.right.left.left;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.right.left;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.right;
		System.out.println(test.value + " next: " + getNextNode(test).value);
		test = head.right.right; // 10's next is null
		System.out.println(test.value + " next: " + getNextNode(test));
	}
}