Freiheit Freiheit - 14 days ago 3
Java Question

Java SimpleDateFormat for time zone with a colon separator?

I have a date in the following format:

2010-03-01T00:00:00-08:00


I have thrown the following SimpleDateFormats at it to parse it:

private static final SimpleDateFormat[] FORMATS = {
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ"), //ISO8601 long RFC822 zone
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssz"), //ISO8601 long long form zone
new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss"), //ignore timezone
new SimpleDateFormat("yyyyMMddHHmmssZ"), //ISO8601 short
new SimpleDateFormat("yyyyMMddHHmm"),
new SimpleDateFormat("yyyyMMdd"), //birthdate from NIST IHE C32 sample
new SimpleDateFormat("yyyyMM"),
new SimpleDateFormat("yyyy") //just the year
};


I have a convenience method that uses those formats like so:

public static Date figureOutTheDamnDate(String wtf) {
if (wtf == null) {
return null;
}
Date retval = null;
for (SimpleDateFormat sdf : FORMATS) {
try {
sdf.setLenient(false)
retval = sdf.parse(wtf);
System.out.println("Date:" + wtf + " hit on pattern:" + sdf.toPattern());
break;
} catch (ParseException ex) {
retval = null;
continue;
}
}

return retval;
}


It seems to hit on the pattern
yyyyMMddHHmm
but returns the date as
Thu Dec 03 00:01:00 PST 2009
.

What is the correct pattern to parse this date?

UPDATE: I don't NEED the time zone parsing. I don't anticipate having time sensitive issues moving between zones, but how would I get the "-08:00" zone format to parse????

Unit test:

@Test
public void test_date_parser() {
System.out.println("\ntest_date_parser");
//month is zero based, are you effing kidding me
Calendar d = new GregorianCalendar(2000, 3, 6, 13, 00, 00);
assertEquals(d.getTime(), MyClass.figureOutTheDamnDate("200004061300"));
assertEquals(new GregorianCalendar(1950, 0, 1).getTime(), MyClass.figureOutTheDamnDate("1950"));
assertEquals(new GregorianCalendar(1997, 0, 1).getTime(), MyClass.figureOutTheDamnDate("199701"));
assertEquals(new GregorianCalendar(2010, 1, 25, 15, 19, 44).getTime(), MyClass.figureOutTheDamnDate("20100225151944-0800"));

//my machine happens to be in GMT-0800
assertEquals(new GregorianCalendar(2010, 1, 15, 13, 15, 00).getTime(),MyClass.figureOutTheDamnDate("2010-02-15T13:15:00-05:00"));
assertEquals(new GregorianCalendar(2010, 1, 15, 18, 15, 00).getTime(), MyClass.figureOutTheDamnDate("2010-02-15T18:15:00-05:00"));

assertEquals(new GregorianCalendar(2010, 2, 1).getTime(), MyClass.figureOutTheDamnDate("2010-03-01T00:00:00-08:00"));
assertEquals(new GregorianCalendar(2010, 2, 1, 17, 0, 0).getTime(), MyClass.figureOutTheDamnDate("2010-03-01T17:00:00-05:00"));
}


Output from unit test:

test_date_parser
Date:200004061300 hit on pattern:yyyyMMddHHmm
Date:1950 hit on pattern:yyyy
Date:199701 hit on pattern:yyyyMM
Date:20100225151944-0800 hit on pattern:yyyyMMddHHmmssZ
Date:2010-02-15T13:15:00-05:00 hit on pattern:yyyy-MM-dd'T'HH:mm:ss
Date:2010-02-15T18:15:00-05:00 hit on pattern:yyyy-MM-dd'T'HH:mm:ss
Date:2010-03-01T00:00:00-08:00 hit on pattern:yyyy-MM-dd'T'HH:mm:ss
Date:2010-03-01T17:00:00-05:00 hit on pattern:yyyy-MM-dd'T'HH:mm:ss

Answer

JodaTime's DateTimeFormat to rescue:

String dateString = "2010-03-01T00:00:00-08:00";
String pattern = "yyyy-MM-dd'T'HH:mm:ssZ";
DateTimeFormatter dtf = DateTimeFormat.forPattern(pattern);
DateTime dateTime = dtf.parseDateTime(dateString);
System.out.println(dateTime); // 2010-03-01T04:00:00.000-04:00

(time and timezone difference in toString() is just because I'm at GMT-4 and didn't set locale explicitly)

If you want to end up with java.util.Date just use DateTime#toDate():

Date date = dateTime.toDate();

Wait for JDK7 (JSR-310) JSR-310, the referrence implementation is called ThreeTen (hopefully it will make it into Java 8) if you want a better formatter in the standard Java SE API. The current SimpleDateFormat indeed doesn't eat the colon in the timezone notation.

Update: as per the update, you apparently don't need the timezone. This should work with SimpleDateFormat. Just omit it (the Z) in the pattern.

String dateString = "2010-03-01T00:00:00-08:00";
String pattern = "yyyy-MM-dd'T'HH:mm:ss";
SimpleDateFormat sdf = new SimpleDateFormat(pattern);
Date date = sdf.parse(dateString);
System.out.println(date); // Mon Mar 01 00:00:00 BOT 2010

(which is correct as per my timezone)

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