文档
1.实现方案
1.1.Timer
1.2.线程池
1.3.mq的延时队列
1.4.QUARTZ
1.搭配cron表达式使用 2.支持年,spring不支持年 3.在周几的位置,quartz的周1是2,spring的周1是1
spring框架的定时任务
springboot默认定时任务框架不是QUARTZ,如果需要使用引入即可
2.cron表达式
2.1. 语法:
秒 分 时 日 月 周 年 (spring 不支持年,所以可以不写)
http://www.quartz-scheduler.org/documentation/quartz-2.3.0/tutorials/crontrigger.html
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(1:周末 7:周一) | , - * ? / L # |
Year | NO | empty, 1970-2099 | , - * / |
特殊字符:
- , :枚举;
(cron="7,9,23****?")
: 任意时刻的7,9,23秒启动这个任务; - -:范围:
(cron="7-20****?"")
:任意时刻的7-20秒之间,每秒启动一次 - *:任意;
- /:步长;
(cron="7/5****?")
:第7秒启动,每5秒一次;(cron="*/5****?")
:任意秒启动,每5秒一次; - ?:(出现在日和周几的位置):为了防止日和周冲突,在周和日上如果要写通配符使用?
(cron="***1*?")
:每月的1号,而且必须是周二然后启动这个任务; - L:(出现在日和周的位置)”,last:最后一个
(cron="***?*3L")
:每月的最后一个周二(1:周末 2:周一 3:周二 4:周三 5:周四 6:周五 7:周六) - W:Work Day:工作日
(cron="***W*?")
:每个月的工作日触发(cron="***LW*?")
:每个月的最后一个工作日触发 - #:第几个
(cron="***?*5#2")
:每个月的 第2个周4
2.2. 示例:
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 L-2 * ? | Fire at 10:15am on the 2nd-to-last 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. |
2.3.在线Cron表达式生成器
3.SpringBoot整合
3.1 开启定时任务
整合步骤:
- @EnableScheduling【spring 默认是使用自己的定时任务,如果想整合Quartz,参考官方】
- @Scheduled
- 定时任务配置类:TaskSchedulingAutoConfiguration
@Slf4j
@Component
@EnableScheduling
public class HelloScheduled {
/**
* 周二的任意秒启动,每隔五秒执行一次
* 1、spring中不支持第七位(年)
* 2、sping中1-7,分别代表周一到周七
*/
@Scheduled(cron = "*/5 * * ? * 2")
public void hello() {
log.info("hello...");
}
}
3.2 定时任务+异步任务
定时任务默认情况排队执行,所以前一个任务超时后面任务也会超时
解决方案: 方案1:业务方法自己作异步编排【CompletableFuture.runAsync】 方案2:修改定时任务线程池的线程个数(默认为1)【spring.task.scheduling.pool.size=5】(部分版本有bug,不一定生效) 方案3:让定时任务异步执行
方案3:让定时任务异步执行 整合步骤:
- @EnableAsync
- @Async
- 异步配置类:TaskExecutionAutoConfiguration
- 配置线程池:
- 核心线程数spring.task.execution.pool.core-size=20
- 最大线程数 spring.task.execution.pool.max-size=50
- 配置线程池:
@Slf4j
@Component
@EnableAsync// 普通service方法也可以标注异步执行
@EnableScheduling
public class HelloScheduled {
@Async
@Scheduled(cron = "* * * ? * 2")// 周二的任意秒启动,每秒执行一次
public void hello() throws InterruptedException {
log.info("hello...");
Thread.sleep(3000);
}
}
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