springboot中用fastjson处理返回值为null的属性值

@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {
 public FastJsonHttpMessageConverter fastJsonHttpMessageConverter() {
    FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();

    FastJsonConfig fastJsonConfig = new FastJsonConfig();
    //todo  这里进行配置，空和null，不返回
    fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    SerializeConfig serializeConfig = SerializeConfig.globalInstance;
    serializeConfig.put(LocalDateTime.class, LocalDateTimeSerializer.instance);
    fastJsonConfig.setSerializeConfig(serializeConfig);

    List<MediaType> mediaTypeList = new ArrayList<>();
    mediaTypeList.add(MediaType.APPLICATION_JSON_UTF8);
    mediaTypeList.add(MediaType.APPLICATION_JSON);
    fastJsonHttpMessageConverter.setSupportedMediaTypes(mediaTypeList);
    fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
    return fastJsonHttpMessageConverter;
  }
}

@Bean
  public HttpMessageConverters fastJsonHttpMessageConverters(){
    FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
    FastJsonConfig fastJsonConfig = new FastJsonConfig();
    fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
    fastJsonConfig.setDateFormat("yyyy-MM-dd");
    fastConverter.setFastJsonConfig(fastJsonConfig);
    HttpMessageConverter<?> converter = fastConverter;
    return new HttpMessageConverters(converter);
  }