How to change Groovy Date format

Question

I want to get my dates into a format like this: 2010-10-01

How do I do this?

Also, I grabbed this from another question:

use (groovy.time.TimeCategory) {

Date date = Date.parse("dd-MMM-yyyy", "15-Mar-2011")

def months = (0..11).collect { 
    (date + it.months).format("MMM/yyyy") 
}

}

How would I change the output of this script to the format I specified above? Thanks:)

Solution

In order to parse it out from a String:

Date.parse( "yyyy-M-d", "2010-10-01" )

In order to format the date that you already have:

def yourDate= new GregorianCalendar( 2010, Calendar.OCTOBER, 1 )

assert String.format('%tY-%<tm-%<td', yourDate) == '2010-10-01'

EDIT (to answer the comment)

groovy:000> yourDate= new GregorianCalendar( 2010, Calendar.OCTOBER, 1 )
===> java.util.GregorianCalendar[...]
groovy:000> print String.format('%tY-%<tm-%<td', yourDate)
2010-10-01===> null
groovy:000>

and backwards:

groovy:000> Date.parse( "yyyy-M-d", String.format('%tY-%<tm-%<td', yourDate) )
===> Fri Oct 01 00:00:00 EDT 2010

current date:

groovy:000> yourDate = Calendar.instance
===> java.util.GregorianCalendar[..]
groovy:000> print String.format('%tY-%<tm-%<td', yourDate) 
2011-11-03===> null

Comments

[blaughli]

Thanks, I'm close. Printing yourdate spits out a very long string, which I assume is the output of GregorianCalendar. How do I get a variable out of this that only has the date as a value, in the format I want? i.e. I want yourdate to print as 2010-10-01

[tolitius]

that is how it prints ( try print String.format('%tY-%<tm-%<td', yourDate) ), I added an example

[blaughli]

I want to use yourDate in the script shown in the question. I want to be able to do : yourDate + it.months

[blaughli]

Also, what if I want yourDate to be the current date, in the same format yyyy-mm-dd?

[blaughli]

Thank you so much tolitius :)

[blaughli]

One final question - Calendar.instance returns 2011-11-03. How would I make it always return "01" in the "days" value? i.e. 01 instead of 03

[tolitius]

yourDate.set( Calendar.DAY_OF_MONTH, 1 )

[blaughli]

Well that pretty much does it. I wish you happiness and success.