SpringBoot中fashjson轉換null值爲空值（正確用法）

@Configuration
public class FJsonConfig {

    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters() {
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        FastJsonConfig config = new FastJsonConfig();
        config.setSerializerFeatures(
                // 保留map空的字段
                SerializerFeature.WriteMapNullValue,
                // 將String類型的null轉成""
                SerializerFeature.WriteNullStringAsEmpty,
                // 將Number類型的null轉成0
                //SerializerFeature.WriteNullNumberAsZero,
                // 將List類型的null轉成[]
                SerializerFeature.WriteNullListAsEmpty,
                // 將Boolean類型的null轉成false
                SerializerFeature.WriteNullBooleanAsFalse,
                // 避免循環引用
                SerializerFeature.DisableCircularReferenceDetect);
        config.setDateFormat("yyyy-MM-dd hh:mm:ss");
        //處理中文亂碼問題
        List<MediaType> fastMediaTypes = new ArrayList<>();
        fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        converter.setSupportedMediaTypes(fastMediaTypes);
        converter.setFastJsonConfig(config);
        return new HttpMessageConverters((HttpMessageConverter<?>) converter);
    }
}