FastJson处理空值字段

package com.ssx.springboottest.Config;

import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;

@Configuration
public class fastJsonConfig extends WebMvcConfigurationSupport {
    /**
     * 使用阿里 FastJson 作为JSON MessageConverter
     * @param converters
     */
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters){
        FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
        FastJsonConfig config = new FastJsonConfig();
        config.setSerializerFeatures(
               // 保留空字段
                SerializerFeature.WriteMapNullValue,
                // 将 String 转换为 null “”
                SerializerFeature.WriteNullStringAsEmpty,
                // 将Number类型的null转换为0
                SerializerFeature.WriteNullNumberAsZero,
                SerializerFeature.WriteNullListAsEmpty,
                SerializerFeature.WriteNullBooleanAsFalse,
                SerializerFeature.DisableCircularReferenceDetect
        );
        converter.setFastJsonConfig(config);
        converter.setDefaultCharset(Charset.forName("UTF-8"));
        ArrayList<MediaType> mediaTypeList = new ArrayList<>();
        mediaTypeList.add(MediaType.APPLICATION_JSON);
        converter.setSupportedMediaTypes(mediaTypeList);
        converters.add(converter);
        
    }
}