Hi,
(Clocks change, cue bugs in my code surfacing).
We are using joda-time 1.6 to persist a textual representation of a date,
like so:
String dateText =
ISODateTimeFormat.basicDateTime().print(startDate.getTimeInMillis());
where startDate is a java.util.Calendar.
So this is storing the string "20091030T100600.000Z", for example (the
application is running in GMT).
Later on, that field is retrieved, and we are trying to read the String back
into a DateTime, then format for presentation on a web page.
DateTimeFormatter formatter =
DateTimeFormat.forPattern("yyyyMMdd'T'HHmmss.SSSZ"); // The pattern is
specified externally
String text = "20091030T100600.000Z"; // Read from persistent storage
really.
DateTime date = formatter.parseDateTime(text);
// ... then format the DateTime according to the client's preferred style...
This fails with:
java.lang.IllegalArgumentException: Invalid format: "20091030T100600.000Z"
is malformed at "Z"
at
org.joda.time.format.DateTimeFormatter.parseDateTime(DateTimeFormatter.java:673)
So I wrote some characterization tests to aid my understanding of the API.
/**
* Passes.
*
* @throws Exception
*/
@Test
public void roundTrippingOfJodaTimeDates() throws Exception {
DateTimeFormatter formatter = ISODateTimeFormat.basicDateTime();
DateTime instant = new DateTime(2009, 10, 30, 10, 6, 0, 0);
String now = formatter.print(instant.getMillis());
assertEquals("20091030T100600.000Z", now);
DateTime rehydrated = formatter.parseDateTime(now);
assertEquals(instant, rehydrated);
}
/**
* This test passes.
*
* @throws Exception
*/
@Test
public void parsingDateTimeWithExplicitPatternAndLongFormOfTimezone()
throws Exception {
DateTimeFormatter formatter =
DateTimeFormat.forPattern("yyyyMMdd'T'HHmmss.SSSZ");
String text = "20091030T100600.000+00:00";
DateTime date = formatter.parseDateTime(text);
assertNotNull(date);
}
/**
* This test fails, when attempting to parseDateTime.
* @throws Exception
*/
@Test
public void parsingDateTimeWithExplicitPatternAndShortFormOfTimezone()
throws Exception {
DateTimeFormatter formatter =
DateTimeFormat.forPattern("yyyyMMdd'T'HHmmss.SSSZ");
String text = "20091030T100600.000Z";
DateTime date = formatter.parseDateTime(text);
assertNotNull(date);
}
AFAICT, the difference is that the formatter created in
ISODateTimeFormat.basicDateTime() calls
DateTimeFormatterBuilder.appendTimeZoneOffset(String, boolean, int, int)
passing in "Z" as the zeroOffsetParameter, but when I call
DateTimeFormat.forPattern(String), null gets passed into the same API method
as the zeroOffsetText parameter. This test demonstrates that it is possible
to construct a DateTimeFormatter which will happily parse the string, but I
can't see a way of getting this without creating my own code to parse a
pattern and create a DateTimeFormatter, which I'd like to avoid.
/**
* This passes, but I'd have to create my own parser to do this, which
feels painful.
*
* @throws Exception
*/
@Test
public void parsingDateTimeWithExplicitBuilderAndShortFormOfTimezone()
throws Exception {
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
.appendYear(4, 4)
.appendMonthOfYear(2)
.appendDayOfMonth(2)
.appendLiteral('T')
.appendHourOfDay(2)
.appendMinuteOfHour(2)
.appendSecondOfMinute(2)
.appendLiteral('.')
.appendSecondOfDay(3)
.appendTimeZoneOffset("Z", false, 2, 2)
.toFormatter();
String text = "20091030T100600.000Z";
DateTime date = formatter.parseDateTime(text);
assertNotNull("Can cope with Z literal", date);
text = "20091030T100600.000+00:00";
date = formatter.parseDateTime(text);
assertNotNull("Can cope with offset", date);
}
Can anyone point out what I'm doing wrong? Why can't I round-trip the value
in the way that I'm currently trying, using
DateTimeFormat.forPattern(String) or similar?
Regards,
James
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