复杂参数

• Map、Model：（map、model里面的数据会被放在request的请求域 request.setAttribute）

    @GetMapping("/params")
    public String testParam(Map<String,Object> map,
                            Model model,
                            HttpServletRequest request,
                            HttpServletResponse response){
        map.put("hello","world666");
        model.addAttribute("world","hello666");
        return "forward:/success";
    }

    @ResponseBody
    @GetMapping("/success")
    public Map success(HttpServletRequest request){
        Map<String,Object> map = new HashMap<>();
        Object hello = request.getAttribute("hello");
        Object world = request.getAttribute("world");
        map.put("hello",hello);
        map.put("world",world);
        return map;
    }