Cron Expression

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Revision as of 02:02, 24 January 2011 by imported>Aeric
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A cron expression is a compact syntax used to specify a repeating sequence of times.

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Warning: Be careful when specifying a cron expression. Kicking off a lengthy process at frequent intervals can impair system performance.

To define a cron expression
  • Specify a repetition interval in Quarz scheduler cron format:
        Secs Mins Hrs DayOfMon Mon DayOfWk Yr
    where:
  • Values are separated by one or more spaces
  • Seconds, minutes, and hours are zero-based
  • Day and month values are 1-based
  • Month can be specified as either 1-12 or JAN-DEC
  • Day of week can be specified as either 1-7 or SUN-SAT
  • Values can be specified as:
  • ? - Don't care
  • * - All
  • A range - Two values separated by a hyphen: 0-3 (first through fourth)
  • An interval - A starting value an interval separated by a slash: 0/5 (zeroth and every fifth)
  • A list - Multiple values separated by values: 0,1,3-6,10/10
  • Nearest weekday - Value followed by a "W": 15W
  • Last - An "L" by itself (last day of month), or value followed by an "L": 5L (last Friday)

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Tip: To specify a scheduling end date, use a range. For example, to run a job for 3 months starting in April, specify month as APR-JUN. To run it for 2 years starting in 2010, specify year as 2010-2011. And so on.

Example
? ? 13 0,14 * ? *
  • Seconds = ? (don't care)
  • Minutes = ? (don't care)
  • Hours = 13 (1 pm)
  • Day of Month = 0,14 (First and fifteenth--zero-based)
  • Month = * (all)
  • Day of Week = ? (don't care)
  • Year (optional) = * (all)
Learn more: Quartz scheduler cron format