序列化与反序列化二叉树

    String Serialize(TreeNode root) {
        if (root==null){
            return "#!";
        }
        //先序遍历
        String res=root.val+"!";
        res+=Serialize(root.left);
        res+=Serialize(root.right);
        return res;
    }

    TreeNode Deserialize(String str) {
        if (str==null){
            return null;
        }
        String[] nodes=str.split("!");
        Queue<String> queue= new LinkedList<>();
        for (String node : nodes) {
            queue.offer(node);
        }
        return reBuildTree(queue);
    }

    private TreeNode reBuildTree(Queue<String> queue) {
        String poll = queue.poll();
        if ("#".equals(poll)){
            return null;
        }
        TreeNode currNode=new TreeNode(Integer.parseInt(poll));
        currNode.left=reBuildTree(queue);
        currNode.right=reBuildTree(queue);
        return currNode;
    }