解决方案：

使用 Map传参 不使用 HttpServletRequest  

之前 

    @RequestMapping("/hello2")
    public String hello2(HttpServletRequest request) {
        request.setAttribute("user", new User("zhangsan", 23));
        return "hello2";
    }

之后

    @RequestMapping("/hello2")
    public String hello2(Map<String,Object> result) {
        result.put("user", new User("zhangsan", 23));
        return "hello2";
    }

结果