Jackson OffsetDateTime serialization Z instead of +00:00 timezone?

Question

I'm using Spring Boot with the following ObjectMapper:

@Bean
public ObjectMapper objectMapper()
{
    final ObjectMapper mapper = new ObjectMapper();

    mapper.enable(SerializationFeature.INDENT_OUTPUT);

    mapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);  
    mapper.setDateFormat(new StdDateFormat().withColonInTimeZone(true)); // Makes no difference to output
    
    mapper.findAndRegisterModules();

    return mapper;
}

When OffsetDateTimes are serialized and returned in responses, they have a format like this:

"2020-02-28T12:28:29.01Z"
"2020-02-28T12:36:21.885Z"

I would have expected the timezone information at the end to look like this instead:

"2020-02-28T10:41:25.287+00:00"

Is there something I'm missing or doing wrong here, or anyway I can get the timezone information serialized as the +00:00 format instead of Z format?

Many thanks!

Answer 1

The following steps resolve this (taken from https://stackoverflow.com/a/41893238/12177456), thanks also @Ralf Wagner and @deHaar:

<dependency>
  <groupId>com.fasterxml.jackson.datatype</groupId>
  <artifactId>jackson-datatype-jsr310</artifactId>
  <version>2.6.5</version>
</dependency>

public class OffsetDateTimeSerializer extends JsonSerializer<OffsetDateTime>
{
    private static final DateTimeFormatter ISO_8601_FORMATTER = DateTimeFormatter
        .ofPattern("yyyy-MM-dd'T'HH:mm:ssxxx")
        .withZone(ZoneId.of("UTC"));

    @Override
    public void serialize(OffsetDateTime value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException
    {
        if (value == null) {
            throw new IOException("OffsetDateTime argument is null.");
        }

        jsonGenerator.writeString(ISO_8601_FORMATTER.format(value));
    }
}

@Bean
public ObjectMapper objectMapper()
{

    ObjectMapper objectMapper = new ObjectMapper();
    objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
    objectMapper.registerModule(new JavaTimeModule());
    SimpleModule simpleModule = new SimpleModule();

    simpleModule.addSerializer(OffsetDateTime.class, new OffsetDateTimeSerializer());
    objectMapper.registerModule(simpleModule);

    return objectMapper;
}