Parse UTC time format into readable datetime in android

Question

I have an UTC datetime in the format 2019-12-06T06:04:50.022461Z I want to convert into readable datetime in the format dd-mm-yyyy hh:mm:ss. I am not able to convert in the particular format. Any help will be highly appreciated. Thanks

Answer 1

java.time and ThreeTenABP

I am assuming that you want to display the time in your user’s time zone. As you said already, your string is in UTC, and very few users will be happy to read the time in UTC.

    DateTimeFormatter readableFormatter = DateTimeFormatter.ofPattern("dd-MM-uuuu HH:mm:ss");

    String originalString = "2019-12-06T06:04:50.022461Z";
    String readableString = Instant.parse(originalString)
            .atZone(ZoneId.systemDefault())
            .format(readableFormatter);
    System.out.println(readableString);

For the sake of the example I ran this code in America/Sitka time zone. Output was:

05-12-2019 21:04:50

If you did want to display the time in UTC as in the original string:

    String readableString = OffsetDateTime.parse(originalString)
            .format(readableFormatter);

06-12-2019 06:04:50

Don’t go with the classes SimpleDateFormat, TimeZone and Calendar used in the currently accepted answer. They are all poorly designed, SimpleDateFormat in particular is a notorious troublemaker and also cannot parse 6 decimals on the seconds as in your string. Those three classes are also all long outdated. Instead I am using java.time, the modern Java date and time API. It is so much nicer to work with. The code is not only shorter, I think that you will also find it clearer to read (either immediately or when you get used to the fluent style).

I am exploiting the fact that your original string is in ISO 8601 format. The classes of java.time parse ISO 8601 format as their default, that is, without any explicit formatter.

For the vast majority of purposes you shold not want to convert from one string format to another, though. Inside your program keep your date and time as an Instant or other proper date/time object. only convert to a string when a string is needed in the interface.

Question: Doesn’t java.time require Android API level 26?

java.time works nicely on both older and newer Android devices. It just requires at least Java 6.

• In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
• In non-Android Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
• On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

• Oracle tutorial: Date Time explaining how to use java.time.
• Java Specification Request (JSR) 310, where java.time was first described.
• ThreeTen Backport project, the backport of java.time to Java 6 and 7 (ThreeTen for JSR-310).
• ThreeTenABP, Android edition of ThreeTen Backport
• Question: How to use ThreeTenABP in Android Project, with a very thorough explanation.
• Wikipedia article: ISO 8601

Answer 2

You can use SimpleDateFormat to format the date. Check below:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
sdf.setTimeZone(TimeZone.getTimeZone("UTC"));

Calendar calendar = Calendar.getInstance();

try {
    calendar.setTime(sdf.parse("2019-12-06T06:04:50.022461Z"));
} catch (Exception ex) {
    ex.printStackTrace();
}

SimpleDateFormat returnFormat = new SimpleDateFormat("dd-mm-yyyy hh:mm:ss");
returnFormat.format(calendar.getTime());

Answer 3

You can try this in java 8

    String dateString = "2019-12-06T06:04:50.022461Z";
    DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd").withZone(ZoneOffset.UTC);
    TemporalAccessor date = fmt.parse(dateString);
    Instant time = Instant.from(date);

    DateTimeFormatter fmtOut = DateTimeFormatter.ofPattern("dd-mm-yyyy hh:mm:ss").withZone(ZoneOffset.UTC);
    String newDateString = fmtOut.format(time);