Spring @Scheduled 定时任务 周设置的坑

@Scheduled在spring-context包里。
具体位于org.springframework.scheduling.annotation.Scheduled
其cron字段的注释如下：

/**
 * A cron-like expression, extending the usual UN*X definition to include triggers
 * on the second as well as minute, hour, day of month, month and day of week.
 * 
E.g. {@code "0 * * * * MON-FRI"} means once per minute on weekdays
 * (at the top of the minute - the 0th second).
 * 
The special value {@link #CRON_DISABLED "-"} indicates a disabled cron trigger,
 * primarily meant for externally specified values resolved by a ${...} placeholder.
 * @return an expression that can be parsed to a cron schedule
 * @see org.springframework.scheduling.support.CronSequenceGenerator
 */
String cron() default "";

再看 org.springframework.scheduling.support.CronSequenceGenerator的注释：

/**
 * Date sequence generator for a
 * Crontab pattern,
 * allowing clients to specify a pattern that the sequence matches.
 *
 * 
The pattern is a list of six single space-separated fields: representing
 * second, minute, hour, day, month, weekday. Month and weekday names can be
 * given as the first three letters of the English names.
 *
 * 
Example patterns:
 * 

 * 
"0 0 * * * *" = the top of every hour of every day.
 * 
"*/10 * * * * *" = every ten seconds.
 * 
"0 0 8-10 * * *" = 8, 9 and 10 o'clock of every day.
 * 
"0 0 6,19 * * *" = 6:00 AM and 7:00 PM every day.
 * 
"0 0/30 8-10 * * *" = 8:00, 8:30, 9:00, 9:30, 10:00 and 10:30 every day.
 * 
"0 0 9-17 * * MON-FRI" = on the hour nine-to-five weekdays
 * 
"0 0 0 25 12 ?" = every Christmas Day at midnight
 * 
 *
 * @author Dave Syer
 * @author Juergen Hoeller
 * @author Ruslan Sibgatullin
 * @since 3.0
 * @see CronTrigger
 */
public class CronSequenceGenerator {
}

cron表达式的pattern需要查看 https://www.manpagez.com/man/5/crontab/

field	allowed values
minute	0-59
hour	0-23
day of month	1-31
month	1-12 (or names, see below)
day of week	0-7 (0 or 7 is Sun, or use names)

0和7是周日，那就是：

数字	周几
0	周日
1	周一
2	周二
3	周三
4	周四
5	周五
6	周六
7	周日