springboot RestController 配置fastjson，实体为null时不显示问题

  Springboot 在和fastjson配合使用时，当返回实体为空时拦截不显示问题。在实际业务中，不管返回实体是否为空，都需要显示出来，如果为空则显示null。

解决方案，引入fastjson jar包

   
            com.alibaba
            fastjson
            1.2.22
        

添加配置ResultConfig：

package com.message.config;

/**
 * @author :zoboy
 * @Description:
 * @ Date: Created in 2019-11-18 10:29
 */
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.http.HttpMessageConverters;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;

import java.util.ArrayList;
import java.util.List;

@Configuration
public class ResultConfig {

    /*注入Bean : HttpMessageConverters，以支持fastjson*/
    @Bean
    public HttpMessageConverters fastJsonHttpMessageConverters() {
        FastJsonHttpMessageConverter fastConvert = new FastJsonHttpMessageConverter();
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat,
                SerializerFeature.WriteNullStringAsEmpty,
                SerializerFeature.WriteNullNumberAsZero,
                SerializerFeature.WriteNullListAsEmpty,
                SerializerFeature.WriteMapNullValue,
                SerializerFeature.DisableCheckSpecialChar);
        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);
    }
}

结果：

{
  "code": "0",
  "message": "成功！",
  "data": null
}

解决问题