How to convert String to Enum with an annotation in spring boot

Question

I want to create an annotation that converts String to my Enum object. I have a DTO object that gets a String field named type as request body. Here I want to take that String and covert it to my Enum object with a custom annotation.

Enum object:

public enum Type {

    MOVIE_CAPABLE,
    SERIES_CAPABLE,
    MOVIE_SERIES_CAPABLE
}

DTO object:

@Data
public class ProviderRequest {

    @ConvertToEnum
    private Type type;

    // Other stuff
}

I know that it will work with uppercase String like MOVIE_CAPABLE without any kind of converting but I want to be able to send lowercase string too.

Thanks!

Answer 1

Yes this is possible, you can use @JsonDeserialize annotation on top of private Type type;

Here is the full working implementation.

@Data
@NoArgsConstructor
@AllArgsConstructor
public class ProviderRequest implements Serializable {

    @JsonDeserialize(using = EnumTypeDeserializer.class)
    private Type type;
    // Other stuff
}

public class EnumTypeDeserializer extends JsonDeserializer<Type> {

    @Override
    public Type deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
        final ObjectCodec objectCodec = jsonParser.getCodec();
        final JsonNode node = objectCodec.readTree(jsonParser);
        final String type = node.asText();
        return Type.valueOf(type.toUpperCase());
    }
}