自定义过滤器获取不到session

@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    /**
     * 注册拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**.html").excludePathPatterns("/Ylogin.html","/Yindex.html","/YRegister.html");
    }
}

public class MyInterceptor implements HandlerInterceptor {
    //在请求处理之前进行调用（Controller方法调用之前
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
        System.out.println("开始请求地址拦截");
        //获取session
        HttpSession session = httpServletRequest.getSession();
        if (session.getAttribute("user") != null)
            return true;
        httpServletResponse.sendRedirect("/Ylogin.html");
            return false;
    }
    //请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle被调用");
    }
    //在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("afterCompletion被调用");
    }
}

$.ajax({
            type: "POST",
            url: "/user/doLogin",
            dataType: "json",
            data:user,
            async:false,
            success: function(res) {}
            })