Jackson Serialize Instant to Nanosecond Issue

Question

Jackson serialises java.time.Instant with WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS enabled by default.

It produces JSON

Answer 1

I took Michal's idea above and wrapped the existing com.fasterxml.jackson.datatype.jsr310.DecimalUtils#toBigDecimal(long seconds, int nanoseconds) in a serializer

class ShortInstantSerializer extends StdSerializer {
    ShortInstantSerializer() {
        super(Instant.class);
    }

    @Override
    public void serialize(Instant value, JsonGenerator gen, SerializerProvider provider) throws IOException {
        gen.writeNumber(DecimalUtils.toBigDecimal(value.getEpochSecond(), value.getNano()));
    }
}

Also, if you're going to be reading it back at some point, the value will be deserialized into a Double. To go back do this (thanks inverwebs!)

public static Instant toInstant(Double d) {
    long seconds = d.longValue();
    long micros = Math.round((d - seconds) * 1_000_000);
    return Instant.ofEpochSecond(seconds).plus(micros , ChronoUnit.MICROS);
}