Ajax中使用Web容器对象

public static String getDeviceEventHistory(String deviceId, String timeZone) throws Exception {

//step1. 得到Web容器
WebContext webContext = WebContextFactory.get();
//step2. 得到Web全局对象
HttpServletRequest request = webContext.getHttpServletRequest();
HttpServletResponse tmpres = webContext.getHttpServletResponse();
StringServletResponse res = new StringServletResponse(tmpres);

//step3. 权限控制
String userId = PortalUtil.getUserId(request);
if (userId == null) {
String retHtml = getNonLoginMessage(request);
return retHtml;
}

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//step4. 向request填装参数
request.setAttribute("timeZone", timeZone);
List<AlertEvent> alertEventList = AlertEventLocalServiceUtil.getAlertEventByDeviceId(Long
.valueOf(deviceId), 0, HISTORY_NUM, new AlertEventTimeComparator(false));
request.setAttribute("alertEventList", alertEventList);


        //step5. 解析jsp
String path = "/html/portlet/ext/itms/device_status/history.jsp";
RequestDispatcher rd = webContext.getServletContext().getRequestDispatcher(path);
rd.include(request, res);
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       //step6. 生成html文档，返回客户端
String retHtml = res.getString();
return retHtml;
}