jsp与后台交换数据（安全目录外）

function changebasin(rivername,codepollute){
        $.ajax({
            type: "POST",
            url:  "${ctx}/waterenvironment/riverPollute.vm",
            dataType: "json",
            data:JSON.stringify({"watername":rivername,"code_pollute":codepollute}),
            contentType: "application/json; charset=utf-8",
            success: function(result){
                 //console(result);
                 //alert(result);
                 loadEcharts(result);
                 $("#monitortime").html(result.monitortime);
                 $("#dynastytitle").html(result.title);
                 //$("#stander").addClass('active').siblings('li').removeClass('active');
           }
        });
    }

<ul>
                    <li><a id="dynastytitle" onclick="changebasin('sj','C03');" class="dropdown"></a></li>
                    
                    <li class="sublinks">
                        
                        <a onclick="changebasin('xj','C03');">西江污染物浓度 沿程变化</a>
                        <a onclick="changebasin('bj','C03');">北江污染物浓度 沿程变化</a>
                        <a onclick="changebasin('hj','C03');">贺江污染物浓度 沿程变化</a>
                        <a onclick="changebasin('xxj','C03');">新兴江污染物浓度 沿程变化</a>
                    </li>
                </ul>

@SuppressWarnings("unchecked")
    @RequestMapping("/riverPollute")
    @ResponseBody
    public Map queryRiverPollute(@RequestBody String  param,HttpSession session){
        Map<String,Object> resultMap = new HashMap();
        
        Map<String,Object> jsonMap = JSONObject.fromObject(param);
        Map paramMap = new HashMap();
        paramMap.put("watername", jsonMap.get("watername"));
        paramMap.put("code_pollute", jsonMap.get("code_pollute"));
        //paramMap {watername=xj, code_pollute=C03}
        resultMap.put("watername",jsonMap.get("watername"));
        
        if(!("".equals(jsonMap.get("watername")))){
            session.setAttribute("watername", jsonMap.get("watername"));
        }else{
            paramMap.put("watername", session.getAttribute("watername"));
        }