问如何在Spring MVC的拦截器中实现客户端请求的控制器方法

EN

@Controller
@Scope("prototype")
@RequestMapping("/hello/")
public class HelloWorld {
    @ResponseType(DataType.JSON)
    @RequestMapping(value="/{username}")
    public UserInfo hellowUser(@PathVariable("username") String username) {
         UserInfo userInfo = new UserInfo();
         userInfo.setUsername(username);
         return userInfo.
    }
}

public void postHandle(HttpServletRequest request,
            HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throw Exception {
    Method method = getRequestedMethod();
    Object result = getResultReturnedByTheMethod();
    ResponseType responseType = method.getAnnotation(ResponseType.class);
    DataType type = responseType.value();
    swich(type) {
    case DataType.JSON : writeJson(result);
    case .......
    ...
    }
}