Override default formatter in JavaTimeModule

Is there a way to override the default formatter used in the JavaTimeModule? Using the @JsonFormat-annotation works fine, but I would like to setup the formatter where I instantiate my ObjectMapper.

I know I can simply register my own JsonDeserializer, but I would prefere to keep using the already existing implementation, so I could still use @JsonFormat where necessary.

[cowtowncoder]

I would actually recommend a different mechanism, so-called “Config overrides”, since use of actual (de)serializers directly is actually not part of supported API (it may work, but might not and may break with newer versions).

Usage with 2.x is like so:

ObjectMapper mapper = ...;
mapper.configOverride(LocalDateTime.class)
    .setFormat(JsonFormat.Value.forPattern("yyyy+MM+dd");   

The main reason why this is preferred is simply that the mechanism of construction of (de)serializers may change as it is considered part of internal API.

[chkpnt]

Yes, I can confirm, it’s working fine. My ObjectMapper is now using a custom default but still be able to use the @JsonFormat-Annotations. Thanks for the hint!

public class ObjectMapperFactory
{
  
  private static final DateTimeFormatter GERMAN_DATE_FORMATTER = DateTimeFormatter.ofPattern("dd.MM.yyyy");

  public ObjectMapper create()
  {
    JavaTimeModule javaTimeModule = new JavaTimeModule();
    javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(GERMAN_DATE_FORMATTER));
    
    return new ObjectMapper()
        .registerModule(new Jdk8Module())
        .registerModule(javaTimeModule)
        .configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false)
        .configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_USING_DEFAULT_VALUE, true);
  }
}