Quartz Scheduler CronTrigger 2012_08_26

CronTrigger is often more useful than SimpleTrigger, if you need a job-firing schedule that recurs based on calendar-like notions, rather than on the exactly specified intervals of SimpleTrigger.

CronTrigger通常比SimpleTrigger用处更大，比如当你需要指定安排表基于日历的，而不是基于精确指定的SimpleTrigger

An example of a complete cron-expression is the string "0 0 12 ? * WED" - which means "every Wednesday at 12:00:00 pm".

Individual sub-expressions can contain ranges and/or lists. For example, the day of week field in the previous (which reads "WED") example could be replaced with "MON-FRI", "MON,WED,FRI", or even "MON-WED,SAT".

Wild-cards (the '' character) can be used to say "every" possible value of this field. Therefore the '' character in the "Month" field of the previous example simply means "every month". A '*' in the Day-Of-Week field would therefore obviously mean "every day of the week".