如何求一棵二叉树的深度

如何求一棵二叉树的深度，是一个非常简单的问题，下面用递归实现

    public static int getLength(Node root){

               if(root==null)

               return 0;

               int depth1;

               int depth2;

               else{

                   depth1 = getLength(root.left);

                   depth2 = getLength(root.right);

                   if(depth1>depth2){

                   return depth1+1;

                   }else{

                   return depth2+1;

                  }

              }

    }