Jquery Ajax 异步请求

navy0168

还是做点笔记，以防下次忘记   
   
   // ajax 请求获取list   function change_third(){         var thirdid=document.getElementById("thirdtree").value;  //第3级       var urlStr="url?id="+thirdid;            document.getElementById("rightFrame").src=urlStr;         $.ajax({ type:"post", url:"<c:url value='/test.do'/>", data:"method=loadSecond&id="+thirdid, success:function(data) {   if(data!=0){  //返回的list  通过json转换  因为老出现编码问题，才改用的var tdjson =  eval("(" + data + ")");var tdatas = tdjson.classify;     var str='';for(var i =0;i<tdatas.length;i++){  var count=tdatas[i].childCount;  //就是那个JavaBean、里的指  var id=tdatas[i].id;  var title=tdatas[i].title;}   }},error:function(msg){alert("error");}});}}
        /**   *  获取 List      **/ public ActionForward loadSecond(ActionMapping mapping, ActionForm form,HttpServletRequest request, HttpServletResponse response)throws Exception {       Long id=Long.parseLong((String)request.getParameter("id"));    //前台获取的id    List test=clsDao.queryParent(id);      response.setCharacterEncoding("GBK");PrintWriter writer = response.getWriter();StringBuffer strXml=null;try {if(parentTree.size()==0){strXml=new StringBuffer("0");}else{ strXml = new StringBuffer("{\"classify\":[");for (int i = 0; i < parentTree.size(); i++) {JavaBean sec=(JavaBean) parentTree.get(i);strXml.append("{\"id\":\"")      .append(sec.getNodeId()).append("\",")                //节点ID      .append("\"childCount\":\"")       .append(sec.getChildNum()).append("\",")          //子节点数目      .append("\"title\":\"")      .append(sec.getTitle()).append("\"}")           //节点标题      .append(",");}strXml = new StringBuffer(strXml.substring(0, strXml.length() - 1));strXml.append("]}");}String res = strXml.toString();writer.print(res); //输出信息writer.flush();   //清空缓存，关闭流writer.close();} catch (Exception e) {e.printStackTrace();}    return null;}
  //如果只要获取一个单独的值，直接打印就OK      StringBuffer strBuf=new StringBuffer("TTT");response.setCharacterEncoding("GBK");PrintWriter writer = response.getWriter();    writer.print(strBuf.toString());     writer.flush();   //清空缓存，关闭流writer.close();