ztree根据Id查找指定节点，并选中节点，把下级节点展开

$(document).ready(function(){
var lastKey;
var productTypeId = $("#productTypeId").val();//获取隐藏域Id值
if(productTypeId!=''){
var zTree = $.fn.zTree.getZTreeObj("treeDemo");
var key = $.trim($("#productTypeId").val());
if (key != "" && key != lastKey) {
nodeList = zTree.getNodesByParam("id", key);//根据Id查找节点
if (nodeList.length > 0) {
for (var i = 0, l = nodeList.length; i < l; i++) { //遍历找到的节点集合
if (nodeList[i].getParentNode()) {
zTree.expandNode(nodeList[i].getParentNode(), true, false, false); //展开其父节点
zTree.expandNode(nodeList[i], true, false, false); //展开其节点
}
zTree.selectNode(nodeList[i]);
$("#citySel").val(nodeList[i].name)
//zTree.updateNode(nodeList[i]);（没必要不用更新节点）
}

}
//zTree.refresh(); // 很重要，否则节点状态更新混乱。（勿刷新树形，否则选中节点也会刷新）
lastNodeList = nodeList;
lastKey = key;
}
}

});