摘要： cron is a UNIX tool that has been around for a long time, so its scheduling capabilities are powerful and proven. The CronTrigger class is based on the scheduling capabilities of cron. CronTrigger uses "cron expressions", which are able to create firing schedules such as: "At 8:00am every Monday through Friday" or "At 1:30am every last Friday of the month". Cron expressions are powerful, but can be pretty confusing. This tutorial aims to take some of the mystery out of creating a cron expr 阅读全文