springboot处理返回值中的null为空字符串

package com.drink.sell.configuration;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializerProvider;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

import java.io.IOException;

@Configuration
public class JsonConfig {
@Bean
@Primary
@ConditionalOnMissingBean(ObjectMapper.class)
public ObjectMapper jacksonObjectMapper(Jackson2ObjectMapperBuilder builder)
{
ObjectMapper objectMapper = builder.createXmlMapper(false).build();

// 通过该方法对mapper对象进行设置,所有序列化的对象都将按改规则进行系列化
// Include.Include.ALWAYS 默认
// Include.NON_DEFAULT 属性为默认值不序列化
// Include.NON_EMPTY 属性为 空("") 或者为 NULL 都不序列化,则返回的json是没有这个字段的。这样对移动端会更省流量
// Include.NON_NULL 属性为NULL 不序列化,就是为null的字段不参加序列化
//objectMapper.setSerializationInclusion(Include.NON_EMPTY);
// 字段保留,将null值转为""
objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>()
{
@Override
public void serialize(Object o, JsonGenerator jsonGenerator,
SerializerProvider serializerProvider)
throws IOException, JsonProcessingException
{
jsonGenerator.writeString("");
}
});
return objectMapper;
}
}
posted @ 2020-06-04 16:26  刘浩2561179983  阅读(5198)  评论(0编辑  收藏  举报