作用:将返回实体类中的属性如果为null  变成""

package com.example.micrweb.config;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 org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import java.io.IOException;/*** @author hrui* @date 2023/11/23 3:00*/
@Configuration
public class JacksonConfiguration {/*** 将返回值json格式化的时候,如果为null 变成""* 因SpringBoot 返回默认用jackjson格式化* 而jackson中JacksonAutoConfiguration* 类已经自动配置了一个 ObjectMapper Bean* 这里对ObjectMapper重新定义*/@Beanpublic ObjectMapper objectMapper(){ObjectMapper objectMapper=new ObjectMapper();//设置null序列化时  为""objectMapper.getSerializerProvider().setNullValueSerializer(new JsonSerializer<Object>() {@Overridepublic void serialize(Object o, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {jsonGenerator.writeString("");}});return objectMapper;}//JacksonAutoConfiguration
}

例如

配置之后