请教！登录功能ajax post请求request.getParameter("username")取值为null

本机和测试服务器都能取到值，发布到正式环境上就取值为null，

js代码：
$.ajax({

            url: 'login.action',
            type: 'POST',
            data: {
                "username": L.inputAccount.val(),
                "password": L.inputPassword.val()
            },
            dataType: 'json',
            catch:true,
            success: function (data) {
                console.log(data);
                $btn.button('reset');
                if (data.result) {
                    //跳转地址
                    window.location.href = "view.action";
                } else {
                    L.errorTip.text(data.msg).show();
                }
                $btn.button('reset');
            },
            error: function () {
                L.errorTip.text('请检查网络或联系后台管理人员！').show();
                $btn.button('reset');
            }
        })

后台代码：

@RequestMapping(value="login.action", method = RequestMethod.POST)

@ResponseBody
public Map<String,Object> login(HttpServletRequest req){
    Map<String,Object> model = new HashMap<String,Object>();
    HttpSession session = req.getSession();
    String username = req.getParameter("username");
    String password = req.getParameter("password");
    resultLog.info("登录信息"+username+"----------"+password);
    Map<String,Object> employeeInfo = service.getEmployeeInfo(username,password);
    if(employeeInfo != null && employeeInfo.size()>0){
        model.put("result", true);
        model.put("msg", "登录成功");
        session.setAttribute("onlineuser", employeeInfo);
        session.setAttribute("username", employeeInfo.get("Name"));
        session.setAttribute("ID",employeeInfo.get("ID"));
    }else{
        model.put("result", false);
        model.put("msg", "用户名或密码错误，请重新填写！");
    }
    return model;
}