jsp 页面内，添加成功后跳转回原页面，并弹出添加成功

controller中，返回原来页面，加入info

 adminService.publishActivity(activity);           
            ModelAndView modelAndView = new ModelAndView("/admin/activity_publish");  
            modelAndView.addObject("info", "success");  
            return modelAndView;  

jsp中

<%
if ((String)request.getAttribute("info") == "success") { %>
    <script>
    alert("添加活动成功！");
    </script>
<%}%>