Cron expressions in scheduled tasks

1、cron Definition of expression

cron An expression is a string , The string consists of 6 The spaces are divided into 7 Domains , Each domain represents a time meaning . The format is as follows （ Commonly defined “ year ” The part of can be omitted , What is commonly used in practice is The first six parts consist of ）：

[ second ] [ branch ] [ when ] [ Japan ] [ month ] [ Zhou ] [ year ]

2、cron Definition of each field

Domain	If required	Values and ranges	wildcard
second （Second）	yes	0-59 The integer of	, - * /
branch （Minute）	yes	0-59 The integer of	, - * /
when （Hour）	yes	0-23 The integer of	, - * /
Japan （Day）	yes	1-31 The integer of	, - * ? / L W
month （Month）	yes	1-12 An integer of or JAN-DEC	, - * /
Zhou （DayofWeek）	yes	1-7 The integer of or SUN-SAT	, - * ? / L #
year （Year）	no	1970-2099	, - * /

3、cron Wildcards and cases of

• , This refers to execution at more than two time points . For example “ when ” This field is defined as 8,14,17, It means that they are in the 8 when , The first 14 Hour and at 17 Execute the scheduled task .
  for example ： 0 0 8,14,17 * * ?

• - This is better understood by specifying a continuous range in a domain , If we were “ when ” This field defines 1-6, It means in 1 To 6 Trigger every hour between points , use , Express 1,2,3,4,5,6
  for example ： 0 0 1-6 * * ?

• * All values , It can be read as “ Every time ”. If in “ Japan ” Set... In this field *, It means that it will trigger every day .
  for example ：0 0 0 * ？（ Daily 0 when 0 branch 0 second ）

• ? Indicates that no value is specified . The scenario used is that you don't need to care about the current value of this field . For example, it should be done on the 28 No. 1 triggers an operation , But it doesn't matter what day of the week
  for example ：0 0 0 28 * ?

• / On a domain periodic Trigger , The symbol divides the expression in its field into two parts , The first part is the starting value , It's going to decrease by one unit except seconds , such as stay “ second ” Defined on the 5/30 From The first 5 Seconds to start Every time 30 Execute once , And in the “ branch ” On means from The first 5 Seconds to start Every time 30 Once per minute .
  for example ： 5/30 * * * ?
  for example ：0 5/30 * * ?

• L In English LAST It means , Only in “ Japan ” and “ Zhou ” Use in . stay “ Japan ” Set in , Represents the last day of the month ( According to the current month , If it's February, it will be based on whether it's Runnian ), stay “ Zhou ” Last means Saturday , amount to ”7” or ”SAT”. If in ”L” Add the number before , It means the last . For example, in “ Zhou ” Set up ”7L” This format , said “ Last Saturday of the month ”. For example, every Saturday morning 7 Do it once
  for example ：0 0 7 ? * L

• W Represents the working day closest to the specified date ( Monday to Friday ) Trigger , Only in “ Japan ” Can only be used after a specific number . If in “ Japan ” Upper position ”16W”, It means every month 16 The most recent working day of the . If 16 It happens to be Saturday , Find the nearest Friday (15 Number ) Trigger , If 16 It's the end of the week , Next Monday (17 Number ) Trigger . If 16 It happens to be on weekday ( Monday to Friday ), It will trigger on that day . If it is “1W” It can only be pushed to the next most recent working day of this month, but not to the previous month .

• # Indicates the day of the week of the month , It only works on “ Zhou ” On . For example, in 4#2, The second Wednesday of a month

• LW: These two characters can be used together , On the last working day of a month , The last Friday .

Examples of common expressions

（1）0 0 2 1 * ? * In the month of 1 Early in the morning 2 Adjust the task

（2）0 15 10 ? * MON-FRI From Monday to Friday every morning 10:15 Perform operation

（3）0 15 10 ? 6L 2022-2026 Express 2022-2026 Last Friday morning of each month of the year 10:15 Executive work

（4）0 0 10,14,16 * * ? Every morning 10 spot , Afternoon 2 spot ,4 spot

（5）0 0/30 9-17 * * ? Every half hour during 9 to 5 working hours

（6）0 0 12 ? * WED Every Wednesday at noon 12 spot

（7）0 0 12 * * ? Every day at noon 12 Some trigger

（8）0 15 10 ? * * Every morning 10:15 Trigger

（9）0 15 10 * * ? Every morning 10:15 Trigger

（10）0 15 10 * * ? * Every morning 10:15 Trigger

（11）0 15 10 * * ? 2022 2022 Every morning in 1986 10:15 Trigger

（12）0 * 14 * * ? Every afternoon 2 Point to the afternoon 2:59 During each of the 1 Minutes to trigger

（13）0 0/5 14 * * ? Every afternoon 2 Point to the afternoon 2:55 During each of the 5 Minutes to trigger

（14）0 0/5 14,18 * * ? Every afternoon 2 Point to 2:55 During and in the afternoon 6 Point to 6:55 During each of the 5 Minutes to trigger

（15）0 0-5 14 * * ? Every afternoon 2 Point to the afternoon 2:05 During each of the 1 Minutes to trigger

（16）0 10,44 14 ? 3 WED Wednesday afternoon in March every year 2:10 and 2:44 Trigger

（17）0 15 10 ? * MON-FRI Monday to Friday morning 10:15 Trigger

（18）0 15 10 15 * ? monthly 15 The morning of 10:15 Trigger

（19）0 15 10 L * ? The morning of the last day of each month 10:15 Trigger

（20）0 15 10 ? * 6L Last Friday morning of the month 10:15 Trigger

（21）0 15 10 ? * 6L 2022-2025 2022 - 2025 Last Friday morning of every month in 2006 10:15 Trigger

（22）0 15 10 ? * 6#3 The third Friday morning of each month 10:15 Trigger