Ext异步加载树(TREE) treeextjson

jsp页面:

  var tree;
  var ne;
  var rightshowMenu;
  Ext.onReady(function(){
  Ext.BLANK_IMAGE_URL="ext/resources/images/aero/s.gif";      
   
  var loader = new Ext.tree.TreeLoader({
    url: "bookShop.do?parameter=treedata"
   });
  
  loader.on("beforeload", function(loader, node){
     this.baseParams.id = (node.id);
    });
  var root = new Ext.tree.AsyncTreeNode({
    id: "root",
    text: "",
    draggable: true //设置根节点是否可拖拽
   });
  
  tree = new Ext.tree.TreePanel({
    renderTo: "tree-div",
    useArrows: true,
       autoScroll: true,
       animate: true,
       containerScroll: true,
       rootVisible: false,
       border: false,
       root:root,
    enableDD: true//允许拖拽
   // listeners:{contextmenu:showMenu}
   });
  <%
  for(int i=0;i<listrose.size();i++)
  {
    Rose rose=listrose.get(i);
  %>
  var croot=new Ext.tree.AsyncTreeNode({
  id:"<%=rose.getId()%>",
  text:"<%=rose.getName()%>",
  allowDrag: false, // 在部门树里面，组织不支持拖拽
     loader: loader
  });
  root.appendChild(croot);
  <%
  }
  %>
  tree.getRootNode().expand();
  });


java：
public ActionForward treedata(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
String id = request.getParameter("id");
log.info("展开节点根据 节点ID：：" + id + ",获取子节点信息!");
List<Rose> list = roseBiz.resutlRosebyid(id);

JSONArray json = new JSONArray();
if (null != id && id.length() > 0) {
for (Rose rose : list) {
JSONObject temp = new JSONObject();
temp.put("id", rose.getId());
temp.put("text", rose.getName());
json.add(temp);
}
}else
{
log.info("节点下为空！");
}
log.info("展开节点，获取节点下面的信息：格式化返回::" + json.toString());
writerJSON(response, json.toString());
return null;
}