JSON如何使用Jackson序列化空值而不是空值？

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

import java.io.IOException;

public class NullToEmptyStringSerializer extends JsonSerializer<Object> {

    @Override
    public void serialize(Object value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
        gen.writeString("");
    }
}

import com.fasterxml.jackson.databind.annotation.JsonSerialize;

public class YourEntity {

    private Long id;

    @JsonSerialize(using = NullToEmptyStringSerializer.class)
    private String name;

    // Getters and setters
}

import com.fasterxml.jackson.databind.ObjectMapper;

public class Main {

    public static void main(String[] args) {
        YourEntity entity = new YourEntity();
        entity.setId(1L);
        entity.setName(null);

        ObjectMapper mapper = new ObjectMapper();
        try {
            String jsonString = mapper.writeValueAsString(entity);
            System.out.println(jsonString);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

{"id":1,"name":""}