code: @Bean
    public ViewResolver viewResolver() {
      FreeMarkerViewResolver resolver = new FreeMarkerViewResolver();
      resolver.setCache(true);
      resolver.setSuffix(".ftl");
      resolver.setContentType("text/html;charset=UTF-8");
      return resolver;
    }
docs: Enable spring freemarker viewresolver. All freemarker template names should end with '.ftl'