get方式长度受限，如何将较长数据传递到后台

get方式长度有限制，所以只能用post方式

$.ajax({             url:"${_baseUrl}/dd/sendDataToServer",             type:'post', //数据发送方式             data:{tableJson:tableJson},            async: false,            success: function(response, status, request){                window.location.href="${_baseUrl}/dd/exportDoc";           },           error:function(XMLHttpRequest, textStatus, errorThrown){               /* alert(XMLHttpRequest.status);               alert(XMLHttpRequest.readyState);               alert(textStatus); */               layer.msg("系统错误", {offset:['85%','45%']});              }          });

通过post将数据传递到后台，缓存在session或者servletContext中

@RequestMapping(value = "sendDataToServer",method = RequestMethod.POST,produces = "text/plain; charset=utf-8")    public void exportDocOfDesignTestTrack1(HttpServletResponse response){        String tableJson = request.getParameter("tableJson");        HttpSession session = request.getSession();        session.setAttribute("tableJson", tableJson);    }

然后在ajax的回调方法中，再去访问后台，获取session中的数据，去做逻辑处理；获取数据后清理缓存

@RequestMapping(value = "exportDoc",method = RequestMethod.GET,produces = "text/plain; charset=utf-8")public void exportDoc(HttpServletResponse response){    documentSetionService.setUnlimitedLicense();    HttpSession session = request.getSession();    String tableJson = (String) session.getAttribute("tableJson");    session.removeAttribute("tableJson");}