动态dtree不显示,麻烦帮我看看,愁死了!!!!!!!
这是生成xml的servlet:
package com.handler;
import 
java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import 
javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.dao.DaoTest;
import com.dao.Nodes;
public class NodesPrint extends HttpServlet {
	private static final long serialVersionUID = 1L;
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws 
ServletException, 
IOException {
                  doPost(request, response);
	}
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		   System.out.println("调用servlet生成xml文件");
            request.setCharacterEncoding("utf-8");
            response.setContentType("text/xml;charset=utf-8");
            //response.setHeader("ContentType","text/xml");
            PrintWriter out = response.getWriter();
            DaoTest test = new DaoTest();
     	   ArrayList list=  test.getNodeInfo();     	    
     	   //System.out.println("#"+list.size()+"#");
     	    if(list!=null&&list.size()>0){
     	    	//System.out.println(list.size()+"是长度");
     	    	out.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
     	    	out.println("<nodes>");
     	    	for(int i=0;i<list.size();i++){     	    		
     	    		Nodes node = (Nodes) list.get(i);
     	    		//out.println("<node nodeId='1' parentId='1' hrefAddress='www.baidu.com'>节点</node>");    	    		
     	    		out.println("<node nodeId='"+node.getClassid()+"'parentId='"+node.getParentid()+"'hrefAddress='"+node.getFormid()+"'>"+node.getClassname()+"</node>");
     	    	}
     	    	out.println("</nodes>");
     	    }
	}
}
这是显示的jsp
<%@ page language="java" pageEncoding="utf-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
	<head>
		<title>树形结构</title>
		<script type="text/javascript" src="dtree.js"></script>
		<script type="text/javascript" src="jquery.js"></script>
		<link rel="stylesheet" href="dtree.css" type="text/css"></link>
				<script type="text/javascript">
				  //alert(nodeId+"/"+parentId+"/"+nodeName+"/"+hrefAddress);
					tree = new dTree('tree');//创建一个对象.
					tree.add(0,-1,"这是根节点");
							  $.ajax({  
										url:'NodesPrint',  
										type:'post', //数据发送方式  
										dataType:'xml', //接受数据格式  
										error:function(xml){
				   							     alert('Error loading XML document'+xml);   
											  },
										async: false ,
										success: function(xml){
												  //alert(xml);
												  //alert("ok");