Java MVC Controller 中通过不同方式获取 @PathVariable 参数值

1.最常用，也是最直接使用方法，通过@PathVariable注解获取

    @RequestMapping(value = "/test/{a}")
    public @ResponseBody Object test(@PathVariable String a) {

        return a;
    }

2.需要通用@PathVariable注解批量获取, 只有注解的参数才能得到

    @RequestMapping(value = "/test/{a}")
    public @ResponseBody Object test(@PathVariable String a, HttpServletRequest httpServletRequest) {

        NativeWebRequest webRequest = new ServletWebRequest(httpServletRequest); 
        Map<String, Object> pathVars = (Map<String, Object>) webRequest.getAttribute(View.PATH_VARIABLES, RequestAttributes.SCOPE_REQUEST);
        
        return pathVars;
    }

3.批量获取，不需要任何注解

    @RequestMapping(value = "/test/{a}")
    public @ResponseBody Object test(HttpServletRequest httpServletRequest) {
        NativeWebRequest webRequest = new ServletWebRequest(httpServletRequest);
        Map<String, String> uriTemplateVars = (Map<String, String>) webRequest.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE, RequestAttributes.SCOPE_REQUEST);
        return uriTemplateVars;
    }