求教mui与springmvc框架的问题

if (!"XMLHttpRequest".equalsIgnoreCase(httpServletRequest.getHeader("X-Requested-With"))
|| request.getParameter("ajax") == null) {// 不是ajax请求
httpServletResponse.sendRedirect(httpServletRequest.getContextPath() + this.getSuccessUrl());
} else {
httpServletRequest.getRequestDispatcher("/login/timeout/success").forward(httpServletRequest, httpServletResponse);
}

后台中的过滤器是这样子的，前端ajax访问的时候总是跳不到else里面，小白不明白，有没有大腿带我飞的TAT