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Thursday, August 3. 2006
Java Time Handling Issues
Be warned when using java.util.Date and java.sql.Timestamp; these cannot be converted back and forth cleanly due to different precisions and the way they store dates internally. Unfortunately Java's date handling classes are pretty much well known to have seriously annoying issues. And be especially careful with java.util.Date vs java.sql.Date; the latter isn't 'actually' a timestamp like the former, so times will get truncated.
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This issue gets even richer. It turns out java.sql.Timestamp is really just a thin wrapper around java.util.Date. They do have the same precision, but it is broken and doesn't work right.
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4971405
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5103041
What appeared to be happening in my case was Hibernate doing a compare between the Timestamp and the Date, which should have worked, but didn't.
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4971405
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5103041
What appeared to be happening in my case was Hibernate doing a compare between the Timestamp and the Date, which should have worked, but didn't.
This may be a bit late to help you, but not seeing your data, I would consider storing both dates in the database so you have them for future use instead of just storing a time delta.
To get the time delta, how you would want to approach it would depend on the resolution of time needed. If you need full precision, for example, just use the Date.getTime() function and do a subtraction between the longs, storing that value. If you need number of days, weeks, etc. check out java.util.GregorianCalendar.
To get the time delta, how you would want to approach it would depend on the resolution of time needed. If you need full precision, for example, just use the Date.getTime() function and do a subtraction between the longs, storing that value. If you need number of days, weeks, etc. check out java.util.GregorianCalendar.