Spring boot return JSONArray field of model as null

Question

I have a JSONArray field in the object:

@Column(name = "_history", columnDefinition = "JSON")
@Convert(converter = JSONArrayConverter.class)
private JSONArray history;

and this is JSONArrayConverter:

@JsonSerialize
@Converter(autoApply = true)
public class JSONArrayConverter implements AttributeConverter<JSONArray, String> {

    public static final Logger LOGGER = LoggerFactory.getLogger(JSONObjectConverter.class);

    @Override
    public String convertToDatabaseColumn(JSONArray array) {
        LOGGER.debug(array.toString());
        if (array == null)
            return new JSONArray().toString();
        String data = null;
        try {
            data = array.toString();
        } catch (final Exception e) {
            LOGGER.error("JSON writing error", e);
        }
        return data;
    }

    @Override
    public JSONArray convertToEntityAttribute(String data) {
        if (_EMPTY.equals(data) || data == null || "[]".equals(data))
            return new JSONArray();
        JSONArray array = null;
        try {
            array = new JSONArray(data);
        } catch (final Exception e) {
            LOGGER.error("JSON reading error", e);
        }
        return array;
    }
}

The problem is when requesting the object from MySQL database(history is JSON column and has data), Spring boot returns it as null:

"history": {}

did you verify if the converter logic gets invoked? is the mapping working? — blankCoder, Jun 12 '23 at 16:54
String data = null; <-- seems like that is firing a little too often maybe? — easleyfixed, Jun 12 '23 at 17:06
@easleyfixed it's ok. I changed to https://stackoverflow.com/a/67849195/1240052 but not work — Hajitsu, Jun 12 '23 at 17:39

score 0 · Answer 1 · answered Jun 15 '23 at 15:31

Finally, I solved this issue.

<dependency>
    <groupId>io.hypersistence</groupId>
    <artifactId>hypersistence-utils-hibernate-60</artifactId>
    <version>3.4.3</version>
</dependency>

First, add the above repository to pom.xml. Then changed the codes to below:

@Column(name = "_history", columnDefinition = "json")
@Type(JsonType.class)
private List<Map<String, Object>> history = new ArrayList<>();

and everything works for me.

Spring boot return JSONArray field of model as null

1 Answers1