ISO 8601 with milliseconds and Retrofit

Question

I cannot set properly the date format when using retrofit and trying to read a date like this:

2015-08-29T11:22:09.815479Z

An the GSON converter I'm setting is like this:

GsonConverter gsonConverter = new GsonConverter(
     new GsonBuilder()
            .setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSSSSz")
            .create()
);

Any clues on what's the problem?

Answer 1

Java 8 Instant class can be used to easily parse ISO-8601 timestamps without explicitly setting a format string, for example:

String input = "2018-11-07T00:25:00.073876Z";
Instant instant = Instant.parse(input);

Answer 2

Java Date has millisecond precision so I've been creating the Gson object like so:

Gson gson = new GsonBuilder()
        .setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
        .create();

Of course, in a case like this, the microseconds are being truncated whether you put SSS or SSSSSS. It is also assumed that the last character of the converted string is always a Z.

To explain why your pattern didn't work, you used z (lowercase z) which according to the documentation represents a General Timezone (e.g., Pacific Standard Time; PST; GMT-08:00). Additionally, if you were to use Z (uppercase Z), it would also not work since it represents an RFC 822 time zone (e.g., -0800).

In another scenario where instead of the Z you have a time zone offset (e.g., -08, -0800, or -08:00), you can use X, XX, or XXX to represent an ISO 8610 time zone. But that requires Java 7 or 8 (I don't think Android is compatible with Java 8 at the moment).

---

Another method would be to write your own Gson Serializer and Deserializer; although I haven't tried.

It's also worth looking at java.sql.Timestamp class which is also supported by Gson and has more fine grained precision (nanoseconds) but it's also an option I haven't explored.