SpringBoot ResponseBody返回值处理

1. SpringBoot ResponseBody 返回值中null值处理

@PostMapping(path = "/test", produces = MediaType.APPLICATION_JSON_VALUE)
public Object test() {
		JSONObject jsonObject = new JSONObject();
		jsonObject.put("test","test");
		jsonObject.put("testnull",null);
		ApiResponseVo apiResponseVo = new ApiResponseVo();
		apiResponseVo.setData(jsonObject );
		apiResponseVo.setStatus(0);
		return apiResponseVo;
}
接口返回 (想实现将testnull也进行返回) : 
{
    "data": {
        "test": "test"
    },
    "status": 0
}

import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
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 com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
@Configuration
public class fastJsonConfig extends WebMvcConfigurationSupport {
	@Override
	public void configureMessageConverters(List> converters) {
		FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
		FastJsonConfig config = new FastJsonConfig();
		config.setSerializerFeatures(
				// 保留 Map 空的字段
				SerializerFeature.WriteMapNullValue,
				// 将 String 类型的 null 转成""
//                SerializerFeature.WriteNullStringAsEmpty,
                // 将 Number 类型的 null 转成 0
//                SerializerFeature.WriteNullNumberAsZero,
                // 将 List 类型的 null 转成 []
//                SerializerFeature.WriteNullListAsEmpty,
                // 将 Boolean 类型的 null 转成 false
//                SerializerFeature.WriteNullBooleanAsFalse,
				// 避免循环引用
				SerializerFeature.DisableCircularReferenceDetect
		);
		converter.setFastJsonConfig(config);
		converter.setDefaultCharset(Charset.forName("UTF-8"));
		List mediaTypeList = new ArrayList<>();
		// 解决中文乱码问题，相当于在 Controller 上的 @RequestMapping 中加了个属性 produces = "application/json"
		mediaTypeList.add(MediaType.APPLICATION_JSON);
		converter.setSupportedMediaTypes(mediaTypeList);
		converters.add(converter);
	}
}

2. 拦截responsebody转json,对数据进行二次处理 (字典转换做案例)

2.1> 设置拦截器

import java.nio.charset.StandardCharsets;
import java.util.List;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import com.fintell.dp3.manager.interceptor.LogInterceptor;
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
	@Override
	public void addInterceptors(InterceptorRegistry registry) {
		// 自定义拦截器，添加拦截路径和排除拦截路径
		registry.addInterceptor(getLogInterceptor()).addPathPatterns("/**");
	}
	@Bean
	public LogInterceptor getLogInterceptor() {
		return new LogInterceptor();
	}
	/**
	 * 修改StringHttpMessageConverter默认配置 & Json 默认序列化方式 (改这个方法)
	 */
	@Override
	public void configureMessageConverters(List> converters) {
	    //创建fastJson消息转换器
	    FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
	    //创建配置类
	    FastJsonConfig fastJsonConfig = new FastJsonConfig();
	    //修改配置返回内容的过滤
	    fastJsonConfig.setSerializerFeatures(
	            SerializerFeature.DisableCircularReferenceDetect,
	            SerializerFeature.WriteMapNullValue,
	            SerializerFeature.WriteNullStringAsEmpty
	    );
	    fastConverter.setFastJsonConfig(fastJsonConfig);
	    //将fastjson添加到视图消息转换器列表内
	    converters.add(fastConverter);
	}
}

2.2> 字典注解类

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Dict {
	String type(); 
}

2.3> 序列化类

import java.io.IOException;
import java.lang.reflect.Field;
import org.apache.commons.lang3.StringUtils;
import org.springframework.context.annotation.Configuration;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import lombok.extern.slf4j.Slf4j;
@Slf4j
@Configuration
public class DictJsonSerializer extends JsonSerializer