序列化二叉树

/*
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;
    }
}
*/
public class Solution {
    String Serialize(TreeNode root) {
        StringBuffer sb=new StringBuffer();
        if(root==null){
            sb.append("#,");
            return sb.toString();
        }
        sb.append(root.val+",");
        sb.append(Serialize(root.left));
        sb.append(Serialize(root.right));
        return sb.toString();
    }
    public Integer index=-1;
    TreeNode Deserialize(String str) {
        ++index;
        if(str.length()<=0){
            return null;
        }
        String[] s=str.split(",");
        TreeNode node=null;
        if(!s[index].equals("#")){
            node=new TreeNode(Integer.valueOf(s[index]));
            node.left=Deserialize(str);
            node.right=Deserialize(str);
        }
        return node;
    }
}