akka quertz expressions
CronTrigger Tutorial
Introduction
cron is a UNIX tool that has been around for a long time, so its scheduling capabilities are powerful and proven. TheCronTrigger 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 expression, giving users a resource which they can visit before having to ask in a forum or mailing list.
Format
A cron expression is a string comprised of 6 or 7 fields separated by white space. Fields can contain any of the allowed values, along with various combinations of the allowed special characters for that field. The fields are as follows:
| Field Name | Mandatory | Allowed Values | Allowed Special Characters |
|---|---|---|---|
| Seconds | YES | 0-59 | , - * / |
| Minutes | YES | 0-59 | , - * / |
| Hours | YES | 0-23 | , - * / |
| Day of month | YES | 1-31 | , - * ? / L W |
| Month | YES | 1-12 or JAN-DEC | , - * / |
| Day of week | YES | 1-7 or SUN-SAT | , - * ? / L # |
| Year | NO | empty, 1970-2099 | , - * / |
So cron expressions can be as simple as this: * * * * ? *
or more complex, like this: 0/5 14,18,3-39,52 * ? JAN,MAR,SEP MON-FRI 2002-2010
Special characters
-
*("all values") - used to select all values within a field. For example, "" in the minute field means *"every minute". -
?("no specific value") - useful when you need to specify something in one of the two fields in which the character is allowed, but not the other. For example, if I want my trigger to fire on a particular day of the month (say, the 10th), but don't care what day of the week that happens to be, I would put "10" in the day-of-month field, and "?" in the day-of-week field. See the examples below for clarification. -
-- used to specify ranges. For example, "10-12" in the hour field means "the hours 10, 11 and 12". -
,- used to specify additional values. For example, "MON,WED,FRI" in the day-of-week field means "the days Monday, Wednesday, and Friday". -
/- used to specify increments. For example, "0/15" in the seconds field means "the seconds 0, 15, 30, and 45". And "5/15" in the seconds field means "the seconds 5, 20, 35, and 50". You can also specify '/' after the '' character - in this case '' is equivalent to having '0' before the '/'. '1/3' in the day-of-month field means "fire every 3 days starting on the first day of the month". -
L("last") - has different meaning in each of the two fields in which it is allowed. For example, the value "L" in the day-of-month field means "the last day of the month" - day 31 for January, day 28 for February on non-leap years. If used in the day-of-week field by itself, it simply means "7" or "SAT". But if used in the day-of-week field after another value, it means "the last xxx day of the month" - for example "6L" means "the last friday of the month". When using the 'L' option, it is important not to specify lists, or ranges of values, as you'll get confusing results. -
W("weekday") - used to specify the weekday (Monday-Friday) nearest the given day. As an example, if you were to specify "15W" as the value for the day-of-month field, the meaning is: "the nearest weekday to the 15th of the month". So if the 15th is a Saturday, the trigger will fire on Friday the 14th. If the 15th is a Sunday, the trigger will fire on Monday the 16th. If the 15th is a Tuesday, then it will fire on Tuesday the 15th. However if you specify "1W" as the value for day-of-month, and the 1st is a Saturday, the trigger will fire on Monday the 3rd, as it will not 'jump' over the boundary of a month's days. The 'W' character can only be specified when the day-of-month is a single day, not a range or list of days.
The 'L' and 'W' characters can also be combined in the day-of-month field to yield 'LW', which translates to *"last weekday of the month"*.
#- used to specify "the nth" XXX day of the month. For example, the value of "6#3" in the day-of-week field means"the third Friday of the month" (day 6 = Friday and "#3" = the 3rd one in the month). Other examples: "2#1" = the first Monday of the month and "4#5" = the fifth Wednesday of the month. Note that if you specify "#5" and there is not 5 of the given day-of-week in the month, then no firing will occur that month.
The legal characters and the names of months and days of the week are not case sensitive.MONis the same asmon.
Examples
Here are some full examples:
| Expression | Meaning |
|---|---|
0 0 12 * * ? |
Fire at 12pm (noon) every day |
0 15 10 ? * * |
Fire at 10:15am every day |
0 15 10 * * ? |
Fire at 10:15am every day |
0 15 10 * * ? * |
Fire at 10:15am every day |
0 15 10 * * ? 2005 |
Fire at 10:15am every day during the year 2005 |
0 * 14 * * ? |
Fire every minute starting at 2pm and ending at 2:59pm, every day |
0 0/5 14 * * ? |
Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day |
0 0/5 14,18 * * ? |
Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day |
0 0-5 14 * * ? |
Fire every minute starting at 2pm and ending at 2:05pm, every day |
0 10,44 14 ? 3 WED |
Fire at 2:10pm and at 2:44pm every Wednesday in the month of March. |
0 15 10 ? * MON-FRI |
Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday |
0 15 10 15 * ? |
Fire at 10:15am on the 15th day of every month |
0 15 10 L * ? |
Fire at 10:15am on the last day of every month |
0 15 10 ? * 6L |
Fire at 10:15am on the last Friday of every month |
0 15 10 ? * 6L |
Fire at 10:15am on the last Friday of every month |
0 15 10 ? * 6L 2002-2005 |
Fire at 10:15am on every last friday of every month during the years 2002, 2003, 2004 and 2005 |
0 15 10 ? * 6#3 |
Fire at 10:15am on the third Friday of every month |
0 0 12 1/5 * ? |
Fire at 12pm (noon) every 5 days every month, starting on the first day of the month. |
0 11 11 11 11 ? |
Fire every November 11th at 11:11am. |
Pay attention to the effects of '?' and '*' in the day-of-week and day-of-month fields!
Notes
- Support for specifying both a day-of-week and a day-of-month value is not complete (you must currently use the '?' character in one of these fields).
- Be careful when setting fire times between mid-night and 1:00 AM - "daylight savings" can cause a skip or a repeat depending on whether the time moves back or jumps forward.
CronTrigger教程
介绍
cron的是一种UNIX工具已经存在了很长一段时间，所以它的调度能力是强大的，成熟的。该CronTrigger类是基于的cron的调度能力。
CronTrigger使用“cron的表情”，这是能够创造发射时间表，例如：“在上午8:00逢星期一至星期五”或“上午1:30在每个月的上周五”。
cron的表达式是强大的，但可以相当混乱。本教程的目的是采取一些神秘的创造出一个cron表达式，为用户提供他们可以不必问在一个论坛或邮件列表之前访问的资源。
格式
一个cron表达式是由6或7场用空格隔开的字符串。字段可以包含任何所允许的值的，伴随着该字段的允许的特殊字符的各种组合。字段说明如下：
| 字段名称 | 强制性 | 允许值 | 允许的特殊字符 |
|---|---|---|---|
| 秒 | YES | 0-59 | ， - * / |
| 分钟 | YES | 0-59 | ， - * / |
| 小时 | YES | 0-23 | ， - * / |
| 月日 | YES | 1-31 | ， - *？/ LW |
| 月 | YES | 1-12或JAN-DEC | ， - * / |
| 星期几 | YES | 1-7或SUN-SAT | ， - *？/ L＃ |
| 年 | NO | 空，1970-2099 | ， - * / |
因此，cron的表达式可以很简单，比如这个：* * * *？*
或更复杂的，就像这样：0/5 14,18,3-39,52 *？JAN，MAR，SEP周一至周五2002-2010
特殊字符
-
*（“全价值”） -用于在字段中选择所有值。例如，“ “ 在分钟字段意味着*”每一分钟“。 -
？（“没有特定的值”） -当需要指定的东西中，其中字符是允许两个场中的一个，但不是其他有用的。例如，如果我想我的触发器触发在每月的某一天（例如，第10），但不关心什么恰好是星期几，我会把“10”中的日-月字段，和“？” 在一天的星期领域。请参阅下面的说明例子。 -
--用于指定范围。例如，在一小时场“10-12”表示“小时10，11和12” 。 -
，-用于指定额外的价值。例如，“周一，周三，周五”在一天，一周的实地指“天星期一，星期三和星期五”。 -
/-用于指定的增量。例如，在秒字段“0/15”是指“在0秒，15，30，和45” 。和“5/15”在秒字段表示“秒5，20，35，50” 。你也可以指定'/'的'后'字-在这种情况下，“ '等价于有“0”之前的'/'。中日一个月的领域“1/3”是指“火每3天起在每月的第一天”。 -
L（“最后”） -具有不同的含义中的每个在它被允许在两个字段。例如，在天月的字段中的值“L”表示“这个月的最后一天”-天1月31日，28天为二月非闰年。如果单独用在日常的星期领域，它只是意味着“7”或“SAT”。但是，如果用在日常的星期后场另一个值，这意味着“这个月的最后一天XXX” -例如“6L”表示“本月的最后一个星期五”。当使用'L'选项，它不指定名单的值，或范围，你会得到令人困惑的结果是很重要的。 -
W¯¯（“平日”） -用于指定工作日（周一至周五）最近的某一天。举个例子，如果你要指定“15W”作为天月的字段中的值，意思是：“最近的工作日到本月15日”。因此，如果15日是星期六，触发器将触发上周五的第14名。如果15日是星期天，触发器将触发周一16日。如果15日是星期二，那么它会火上周二15日。然而，如果你指定“1W”作为天，一个月的价值，而1日是星期六，触发器将触发周一3日，因为它不会“跳”过了一个月的天界。当一天-的月份是一个单一的一天，而不是一个范围或数天的列表中的“W”字符只能被指定。
的“L”和“W”的字符，也可在一天月的场结合以产生LW，转化为*。*“最后一个月的平日”。
＃-用于指定月份的“第n”XXX天。例如，在一天的星期领域的“6＃3”的值是指“每月的第三个星期五”（6天=周五和“＃3”=第3人在一个月）。其他的例子：“2＃1”=该月的第一个星期一和“4＃5”=月份的第五星期三。请注意，如果您指定“＃5”并没有5给定的一天，周在本月，就会产生不烧一个月。
合法字符和个星期和天名称不区分大小写。MON是一样的星期一。
示例
下面是一些全例子：
| 表达 | 意思 |
|---|---|
0 0 12 * *？ |
消防中午12点（中午），每天 |
0 15 10？* * |
消防在每天上午10:15 |
0 15 10 * *？ |
消防在每天上午10:15 |
0 15 10 * *？* |
消防在每天上午10:15 |
0 15 10 * *？2005年 |
在2005年火在每天上午10时15 |
0 * 14 * *？ |
火每一分钟，每一天起下午2点和下午2点59分结束 |
0 0/5 14 * *？ |
每天火起下午2点和下午2时55分结束，每5分钟 |
0 0/5 14,18 * *？ |
火灾发生在下午2点和下午2时55分结束，每5分钟，每天火灾起始于下午6时和下午6时55分结束，每5分钟 |
0 0-5 14 * *？ |
火每一分钟，每一天起下午2点和下午2点05分结束 |
0 10,44 14？3 WED |
在三月份火下午2时10分和下午2点44分每星期三。 |
0 15 10？*周一至周五 |
消防上午10:15每周一，周二，周三，周四和周五 |
0 15 10 15 *？ |
消防上午10:15在每个月的第15天 |
0 15 10 L *？ |
消防上午10:15在每个月的最后一天 |
0 15 10？* 6L |
消防上午10:15每个月的最后一个星期五 |
0 15 10？* 6L |
消防上午10:15每个月的最后一个星期五 |
0 15 10？* 6L 2002-2005 |
在2002年，2003年，2004年和2005年的年火上午10:15在每月每上周五 |
0 15 10？* 6＃3 |
消防上午10:15每月的第三个星期五 |
0 0 12 1/5 *？ |
消防中午12点（中午）每5天每月，开始在每月的第一天。 |
0 11 11 11 11？ |
火里11月11日，在上午11点11分。 |
要注意的效果“？和在 - 日期一周和一日月中的字段“*”！
笔记
- 支持用于指定两个日间的星期和日间月的值是不完整的（必须目前使用在这些领域中的一个的“？”字符）。
- 小心设置午夜1:00 AM之间防火时候 - “夏令时”可能会导致跳过或取决于时间向后移动或向前跳了再说。