dubbo3.1 rest protocol :How to specify the SerializerFeature of fastjson

I tried to do this，But it didn't work at all。
@Bean
public HttpMessageConverters fastJsonHttpMessageConverters() {
FastJsonHttpMessageConverter fastConvert = new FastJsonHttpMessageConverter();
FastJsonConfig fastJsonConfig = new FastJsonConfig();
fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat,
SerializerFeature.WriteMapNullValue);
//处理日期时间格式化问题
fastJsonConfig.setDateFormat("yyyy-MM-dd hh:mm:ss");
//处理中文乱码问题
List fastMediaTypes = new ArrayList<>();
fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
fastConvert.setSupportedMediaTypes(fastMediaTypes);
fastConvert.setFastJsonConfig(fastJsonConfig);
return new HttpMessageConverters((HttpMessageConverter) fastConvert);
}