Springboot中怎么利用@Scheduled实现定时任务
使用@Scheduled 可以很容易实现定时任务
spring boot的版本 2.1.6.RELEASE
package com.abc.demo.common;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.EnableScheduling;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import java.text.SimpleDateFormat;import java.util.concurrent.TimeUnit;@EnableScheduling@Componentpublic class ScheduleSetting { private final Logger logger = LoggerFactory.getLogger(Tasks.class); @Scheduled(fixedRate = 10000, initialDelay = 2000) public void scheduleRead() { try { long timeStamp = System.currentTimeMillis(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Thread thread = Thread.currentThread(); System.out.println("cron1任务开始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName()); long endStamp = System.currentTimeMillis(); try { TimeUnit.SECONDS.sleep(20); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("cron1任务正在运行的线程名称：" + thread.getName() + " 结束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp)); System.out.println("++++++++++++++++++++++++"); } catch (Exception e) { logger.error(e.getMessage()); } } @Scheduled(fixedRate = 5000, initialDelay = 1000) public void scheduleConvert() { try { long timeStamp = System.currentTimeMillis(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Thread thread = Thread.currentThread(); System.out.println("cron2任务开始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName()); try { TimeUnit.SECONDS.sleep(10); } catch (InterruptedException e) { e.printStackTrace(); } long endStamp = System.currentTimeMillis(); System.out.println("cron2任务正在运行的线程名称：" + thread.getName() + " 结束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp)); System.out.println("===================="); } catch (Exception e) { logger.error(e.getMessage()); } }}
运行输出内容为
cron2任务开始,start=2019-10-11 17:31:52, threadId=34, threadName=scheduling-1cron2任务正在运行的线程名称：scheduling-1 结束,start=2019-10-11 17:31:52,end=2019-10-11 17:32:02====================cron1任务开始,start=2019-10-11 17:32:02, threadId=34, threadName=scheduling-1cron1任务正在运行的线程名称：scheduling-1 结束,start=2019-10-11 17:32:02,end=2019-10-11 17:32:02++++++++++++++++++++++++cron2任务开始,start=2019-10-11 17:32:22, threadId=34, threadName=scheduling-1cron2任务正在运行的线程名称：scheduling-1 结束,start=2019-10-11 17:32:22,end=2019-10-11 17:32:32……
注：
cron2执行完后才会执行cron1
原因：
spring默认是以单线程执行任务调度
spring的定时任务默认最大运行线程数为1，多个任务执行起来时间会有问题
1.配置线程池
在配置文件application.properties中添加
# 线程池大小spring.task.scheduling.pool.size=5# 线程名前缀spring.task.scheduling.thread-name-prefix=myScheduling-
输出内容变为
cron2任务开始,start=2019-10-11 17:34:48, threadId=34, threadName=myScheduling-1cron1任务开始,start=2019-10-11 17:34:49, threadId=35, threadName=myScheduling-2cron2任务正在运行的线程名称：myScheduling-1 结束,start=2019-10-11 17:34:48,end=2019-10-11 17:34:58====================cron2任务开始,start=2019-10-11 17:34:58, threadId=34, threadName=myScheduling-1cron2任务正在运行的线程名称：myScheduling-1 结束,start=2019-10-11 17:34:58,end=2019-10-11 17:35:08====================cron2任务开始,start=2019-10-11 17:35:08, threadId=57, threadName=myScheduling-3cron1任务正在运行的线程名称：myScheduling-2 结束,start=2019-10-11 17:34:49,end=2019-10-11 17:34:49……
注：
多线程下，cron1和cron2不用互相等待了，但是同一个任务还是需要等待的
2.并发
修改代码
package com.abc.demo.common;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.Async;import org.springframework.scheduling.annotation.EnableAsync;import org.springframework.scheduling.annotation.EnableScheduling;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.stereotype.Component;import java.text.SimpleDateFormat;import java.util.concurrent.TimeUnit;@EnableScheduling@Component@EnableAsyncpublic class ScheduleSetting { private final Logger logger = LoggerFactory.getLogger(Tasks.class); @Async @Scheduled(fixedRate = 10000, initialDelay = 2000) public void scheduleRead() { try { long timeStamp = System.currentTimeMillis(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Thread thread = Thread.currentThread(); System.out.println("cron1任务开始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName()); long endStamp = System.currentTimeMillis(); try { TimeUnit.SECONDS.sleep(20); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("cron1任务正在运行的线程名称：" + thread.getName() + " 结束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp)); System.out.println("++++++++++++++++++++++++"); } catch (Exception e) { logger.error(e.getMessage()); } } @Async @Scheduled(fixedRate = 5000, initialDelay = 1000) public void scheduleConvert() { try { long timeStamp = System.currentTimeMillis(); SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); Thread thread = Thread.currentThread(); System.out.println("cron2任务开始,start=" + simpleDateFormat.format(timeStamp) + ", threadId=" + thread.getId() + ", threadName=" + thread.getName()); try { TimeUnit.SECONDS.sleep(10); } catch (InterruptedException e) { e.printStackTrace(); } long endStamp = System.currentTimeMillis(); System.out.println("cron2任务正在运行的线程名称：" + thread.getName() + " 结束,start=" + simpleDateFormat.format(timeStamp) + ",end=" + simpleDateFormat.format(endStamp)); System.out.println("===================="); } catch (Exception e) { logger.error(e.getMessage()); } }}
输出的内容
cron2任务开始,start=2019-10-11 17:39:53, threadId=57, threadName=task-1cron1任务开始,start=2019-10-11 17:39:54, threadId=59, threadName=task-2cron2任务开始,start=2019-10-11 17:39:58, threadId=61, threadName=task-3cron2任务开始,start=2019-10-11 17:40:03, threadId=63, threadName=task-4cron2任务正在运行的线程名称：task-1 结束,start=2019-10-11 17:39:53,end=2019-10-11 17:40:03====================cron1任务开始,start=2019-10-11 17:40:04, threadId=64, threadName=task-5cron2任务开始,start=2019-10-11 17:40:08, threadId=65, threadName=task-6cron2任务正在运行的线程名称：task-3 结束,start=2019-10-11 17:39:58,end=2019-10-11 17:40:08====================cron2任务开始,start=2019-10-11 17:40:13, threadId=66, threadName=task-7cron2任务正在运行的线程名称：task-4 结束,start=2019-10-11 17:40:03,end=2019-10-11 17:40:13====================cron1任务正在运行的线程名称：task-2 结束,start=2019-10-11 17:39:54,end=2019-10-11 17:39:54
说明：
@EnableAsync开启多线程 @Async标记其为一个异步任务 每个定时任务都是在通过不同的线程来处理，线程名的前缀成了task- 线程默认为10个
修改配置
spring.task.execution.thread-name-prefix=mytask-spring.task.execution.pool.core-size=5
重新运行的输出
cron2任务开始,start=2019-10-11 17:44:00, threadId=56, threadName=mytask-1cron1任务开始,start=2019-10-11 17:44:01, threadId=57, threadName=mytask-2cron2任务开始,start=2019-10-11 17:44:05, threadId=58, threadName=mytask-3cron2任务开始,start=2019-10-11 17:44:10, threadId=59, threadName=mytask-4cron2任务正在运行的线程名称：mytask-1 结束,start=2019-10-11 17:44:00,end=2019-10-11 17:44:10====================cron1任务开始,start=2019-10-11 17:44:11, threadId=60, threadName=mytask-5cron2任务正在运行的线程名称：mytask-3 结束,start=2019-10-11 17:44:05,end=2019-10-11 17:44:15====================cron2任务开始,start=2019-10-11 17:44:15, threadId=58, threadName=mytask-3cron2任务开始,start=2019-10-11 17:44:20, threadId=56, threadName=mytask-1cron2任务正在运行的线程名称：mytask-4 结束,start=2019-10-11 17:44:10,end=2019-10-11 17:44:20====================cron1任务正在运行的线程名称：mytask-2 结束,start=2019-10-11 17:44:01,end=2019-10-11 17:44:01