Topic: Java and dates

[ober]

This might be a stupid question, but how do I take a date in pretty much any format (because our clients specify date formats at the application and question level), and pull out the year/month/day?

Why isn't there a php.net type manual for Java?  ARGH!

[Dumah]

http://download.oracle.com/javase/1.4.2/docs/api/java/text/SimpleDateFormat.html

[webwhy]

Apache Commons DateUtils has several methods that you might find useful.
http://commons.apache.org/lang/api-2.6/org/apache/commons/lang/time/DateUtils.html

I've never used it, but I've seen JodaTime recommended in Stack Overflow threads as well
http://joda-time.sourceforge.net

[PJYelton]

We use SimpleDateFormat also and it works well for us.

[ober]

OK, so I have the following and it's working to get the date in the right format:

Code: [Select]

String pattern = cell.getFormat();
System.out.println(pattern);
Date activity = new Date();
SimpleDateFormat df = new SimpleDateFormat(pattern);
try {
activity = df.parse(cell.getValue());
        System.out.println(df.format(activity));
} catch (ParseException e) {
System.out.println(e.getMessage());
}

MM/dd/yyyy
03/01/2011
MM/dd/yyyy
03/02/2011
MM/dd/yyyy
03/03/2011
MM/dd/yyyy
03/04/2011
MM/dd/yyyy
03/05/2011
MM/dd/yyyy
03/06/2011
MM/dd/yyyy
03/07/2011
MM/dd/yyyy
03/09/2011

But now I need to grab the specific portions of the date.  Do I need to create new patterns for each portion or is there an easier way to grab the day, month, and year and put them into separate variables?

[Mike]

http://download.oracle.com/javase/6/docs/api/java/util/Calendar.html

[ober]

Is that really what I need though?  That seems like it's only for dealing with the existing calendar.  I have a date object that I want to parse.  I don't see how I can pass a date variable into that.  Or am I blind?

[Mike]

Look at the sample code http://download.oracle.com/javase/6/docs/api/java/util/GregorianCalendar.html

[webwhy]

obes...

calendar creation is relatively expensive in java.  so at the very least avoid local creation especially in loops...

[ober]

I'm only creating it once.

[hans]

We use JodaTime where I work now, and it's better than trying to work with the Java Calendar object, which is pretty much required if you don't want to use deprecated methods.

[ober]

OK, got it working.  Thanks for the help.