设计一个打印整棵树的打印函数

package com.harrison.class07;
public class Code06_PrintBinaryTree {
  public static class Node {
    public int value;
    public Node left;
    public Node right;
    public Node(int data) {
      this.value = data;
    }
  }
  public static void printTree(Node head) {
    System.out.println("Binary Tree:");
    printInOrder(head, 0, "H", 17);
    System.out.println();
  }
  public static void printInOrder(Node head, int height, String to, int len) {
    if (head == null) {
      return;
    }
    printInOrder(head.right, height + 1, "v", len);
    String val = to + head.value + to;
    int lenM = val.length();
    int lenR = (len - lenM) / 2;
    int lenL = len - lenM - lenR;
    val = getSpace(lenL) + val + getSpace(lenR);
    System.out.println(getSpace((height * len)) + val);
    printInOrder(head.left, height + 1, "^", len);
  }
  public static String getSpace(int num) {
    String space = " ";
    StringBuffer bf = new StringBuffer();
    for (int i = 0; i < num; i++) {
      bf.append(space);
    }
    return bf.toString();
  }
  public static void main(String[] args) {
    Node head = new Node(1);
    head.left = new Node(-222222222);
    head.right = new Node(3);
    head.left.left = new Node(Integer.MIN_VALUE);
    head.right.left = new Node(55555555);
    head.right.right = new Node(66);
    head.left.left.right = new Node(777);
    printTree(head);
    head = new Node(1);
    head.left = new Node(2);
    head.right = new Node(3);
    head.left.left = new Node(4);
    head.right.left = new Node(5);
    head.right.right = new Node(6);
    head.left.left.right = new Node(7);
    printTree(head);
    head = new Node(1);
    head.left = new Node(1);
    head.right = new Node(1);
    head.left.left = new Node(1);
    head.right.left = new Node(1);
    head.right.right = new Node(1);
    head.left.left.right = new Node(1);
    printTree(head);
  }
}