Spring boot，Jackson在序列化中将空字符串转换为NULL

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
public class YourApplication {

    public static void main(String[] args) {
        SpringApplication.run(YourApplication.class, args);
    }

    @Bean
    public ObjectMapper objectMapper() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);
        return objectMapper;
    }
}