java.time DateTimeFormatter pattern for timezone offset

Question

I am trying to parse: 2014-05-02-10.45.05.993280-5:00 where the -5:00 is the offset from UTC. Using a java.time DateTimeFormatter in Java 8.

For the first bit I have the following: yyyy-MM-dd-HH.mm.ss.SSSSSS however, I can't figure out what the pattern should be to parse the offset also.

If I had the offset with 4 digits (-05:00) I could use: yyyy-MM-dd-HH.mm.ss.SSSSSSxxx, but this doesn't work for 3 digits.

Any ideas?

Lucic

Answer 1

Use capital letter X instead of x, hence XXX. The difference is that big X can recognize the input letter "Z" as UTC-Offset +00:00 while small pattern letter X cannot.

Suggested pattern:

yyyy-MM-dd-HH.mm.ss.SSSSSSXXX

Please be also aware of following JDK-bug:

java.time.format.DateTimeFormatter cannot parse an offset with single digit hour

UPDATE:

I have now tested the described workaround in the bug-log.

String input = "2014-05-02-10.45.05.993280-5:00";
DateTimeFormatter f = new DateTimeFormatterBuilder()
        .appendPattern("yyyy-MM-dd-HH.mm.ss.SSSSSS")
        .parseLenient()
        .appendOffset("+HH:MM", "Z")
        .toFormatter();
System.out.println(f.parse(input, ZonedDateTime::from));

But it throws an exception:

Exception in thread "main" java.time.format.DateTimeParseException: Text '2014-05-02-10.45.05.993280-5:00' could not be parsed at index 26 at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1947) at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1849) at HelloWorld.main(HelloWorld.java:16)

So lenient parsing does not help either. So there are now only three options left for you:

• Use workaround suggested by bug reporter: [...] workaround is to parse the date/time separately, use a hand coded parser for the offset and combine the LocalDateTime with the hand parsed offset. Not an easy work around.

• Try your own specialized string preprocessing. If you have a fixed format then you can try to insert the zero-digit at position 26 (if the total input length is one digit too small).

• Or you use an external library which can do this. My library Time4J (v4.0) can do that if you are willing to add an extra dependency. See this code:

String input = "2014-05-02-10.45.05.993280-5:00";
ZonalDateTime zdt =
    ZonalDateTime.parse(
        input,
        Moment.localFormatter("yyyy-MM-dd-HH.mm.ss.SSSSSSXXX", PatternType.CLDR));
System.out.println(zdt); // 2014-05-02T10:45:05,993280UTC-05:00
ZonedDateTime result = zdt.toTemporalAccessor();

Update: According to JDK-bug-status, the bug has been fixed for Java-9, but a backport for Java-8 does not seem to be available though.

Frater

The pattern does not work...but the link to the bug looks like exactly my issue. I tried the builder suggestion, but that didn't appear to work either. – Lucic

@Lucic You are right. Sorry that you suffer from the bug. Please see also my update if you can use any of the alternative workarounds. – Frater

Answer 2

All the answers are good. The java8+ have these patterns for parsing and formatting timezone: V, z, O, X, x, Z.

Here's they are, for parsing, according to rules from the documentation :

   Symbol  Meaning                     Presentation      Examples
   ------  -------                     ------------      -------
   V       time-zone ID                zone-id           America/Los_Angeles; Z; -08:30
   z       time-zone name              zone-name         Pacific Standard Time; PST
   O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
   X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15;
   x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15;
   Z       zone-offset                 offset-Z          +0000; -0800; -08:00;

But how about formatting? Here's a sample for a date (assuming ZonedDateTime) that show these patters behavior for different formatting patters:

// The helper function:
static void printInPattern(ZonedDateTime dt, String pattern) {
    System.out.println(pattern + ": " + dt.format(DateTimeFormatter.ofPattern(pattern)));
}        

// The date:
String strDate = "2020-11-03 16:40:44 America/Los_Angeles";
DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss zzzz");
ZonedDateTime dt = ZonedDateTime.parse(strDate, format);
// 2020-11-03T16:40:44-08:00[America/Los_Angeles]

// Rules:
// printInPattern(dt, "V");     // exception!
printInPattern(dt, "VV");       // America/Los_Angeles
// printInPattern(dt, "VVV");   // exception!
// printInPattern(dt, "VVVV");  // exception!
printInPattern(dt, "z");        // PST
printInPattern(dt, "zz");       // PST
printInPattern(dt, "zzz");      // PST
printInPattern(dt, "zzzz");     // Pacific Standard Time
printInPattern(dt, "O");        // GMT-8
// printInPattern(dt, "OO");    // exception!
// printInPattern(dt, "OO0");   // exception!
printInPattern(dt, "OOOO");     // GMT-08:00
printInPattern(dt, "X");        // -08
printInPattern(dt, "XX");       // -0800
printInPattern(dt, "XXX");      // -08:00
printInPattern(dt, "XXXX");     // -0800
printInPattern(dt, "XXXXX");    // -08:00
printInPattern(dt, "x");        // -08
printInPattern(dt, "xx");       // -0800
printInPattern(dt, "xxx");      // -08:00
printInPattern(dt, "xxxx");     // -0800
printInPattern(dt, "xxxxx");    // -08:00
printInPattern(dt, "Z");        // -0800
printInPattern(dt, "ZZ");       // -0800
printInPattern(dt, "ZZZ");      // -0800
printInPattern(dt, "ZZZZ");     // GMT-08:00
printInPattern(dt, "ZZZZZ");    // -08:00

In the case of positive offset the + sign character is used everywhere(where there is - now) and never omitted.

This well works for new java.time types. If you're about to use these for java.util.Date or java.util.Calendar - not all going to work as those types are broken(and so marked as deprecated, please don't use them)

Sedition

The FORMATTING of the symbol is what was causing me issues. Thank you for this detailed example! – Navada

Answer 3

Offset for SimpleDateFormat sign is Z check Java7 or Java8 SimpleDateFormat API.

Then, your parser format for String

2014-05-02-10.45.05.993280-5:00

must be:

yyyy-MM-dd-HH.mm.ss.SSSSSSZ

UPDATE: for DateTimeFormatter the offset Patterns for Formatting and Parsing are:

O       localized zone-offset       offset-O          GMT+8; GMT+08:00; UTC-08:00;
X       zone-offset 'Z' for zero    offset-X          Z; -08; -0830; -08:30; -083015; -08:30:15;
x       zone-offset                 offset-x          +0000; -08; -0830; -08:30; -083015; -08:30:15;
Z       zone-offset                 offset-Z          +0000; -0800; -08:00;

Your desired pattern in DateTimeFormatter is X.

Ocelot

I am using a DateTimeFormatter and adding a Z does not appear ot work – Lucic

You linked to Java 7 twice. Java 8 API is here. – Daddylonglegs

I tried variations of this and cant get it to print the format "+00:00" on a GMT time. It will only print "+0000" . On the other hand, if the timezone is offset by at least 1, then DateTimeFormatter.ISO_OFFSET_DATE_TIME will print the former desired pattern. – Sheepfold