highcharts与ajax的应用

当获取大数据量时，为了缓解浏览器的压力，以免造成页面停留，需要把后台的数据分批提取到页面。方法：

<1>前台js：

<2>后台action：

 public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response)
   throws IOException, InterruptedException {

  response.setContentType("text/html;charset=utf-8");

  String index = request.getParameter("index");// 当前记录id
  int currentid = 0;// 当前返回的记录数下标
  int total = 0;// 总记录数

  if (!"".equals(index) && index != null) {
   currentid = Integer.parseInt(index);
  }
  PrintWriter pw = response.getWriter();

  List all = new ArrayList();

  for (int i = 0; i < 100; i++) {
   double num = Math.random() * 100;
   all.add((int) num);
  }

  List each = new ArrayList();
  for (int i = currentid-20; i < currentid; i++) {// 根据ajax传递的id将数据分块传递，每次取20个数据
   if(currentid<=all.size()){
    each.add(all.get(i));
   }
  }
  
  JSONArray json = JSONArray.fromObject(each);// 转化成json对象
  json.put(each.size(), currentid);// currentindex ->json
  json.put(each.size() + 1, all.size());// total ->json
  pw.println(json);
  
  System.out.println("each json is "+json);
  // pw.println(currentid);
  return null;

  // return new ActionForward("/ajax.jsp");
 }