SpringBoot定时任务 @Scheduled 没有准时执行的原因及解决方案

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wx5da03a3bd2999 2022-12-21 11:20:46 ©著作权

文章标签 定时任务 Async System 文章分类 Java 后端开发

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问题：

在spring boot 项目中设置了共13个定时任务，突然有一天部分定时任务就不再执行了，重启程序定时任务也不执行，莫名其妙，查了好多资料，以下是关于我查到的关于定时任务突然停掉的一些原因。

排查：

查到了大部分经验说是spring boot中得定时任务都时单线程得，要进行多线程执行；

单线程测试：

package com.example.demo.conf;

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.TimeUnit;
import static java.lang.Thread.sleep;

@Component
//@EnableAsync        //开启多线程
public class SaticScheduleTask {
    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron1() {
        System.out.println("第1个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron2() {
        System.out.println("第2个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron3() {
        System.out.println("第3个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron4() {
        System.out.println("第4个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron5() {
        System.out.println("第5个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 1 * * ?")
    public void jobCron6() {
        System.out.println("第6个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron7() {
        System.out.println("第7个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 0 1 11 ?")
    public void jobCron8() {
        System.out.println("第8个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 2 * * ?")
    public void jobCron9() {
        System.out.println("第9个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron10() throws InterruptedException {
        System.out.println("第10个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(600);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT1M")
    public void jobCron11() throws InterruptedException {
        System.out.println("第11个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(120);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT20S")
    public void jobCron12() throws InterruptedException {
        System.out.println("第12个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(360);
    }

    @Async
    @Scheduled(cron = "0 45 10 * * ?")
    public void jobCron13() {
        System.out.println("第13个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
}

测试结果：当有多个定时任务时，其中一个耗时比较长会影响其他定时任务执行，执行结果可以看出设定的第13个定时任务为每天10:45执行，到时间并未执行

SpringBoot定时任务 @Scheduled 没有准时执行的原因及解决方案_定时任务

解决方法：

方法一：改为多线程：（经过反复测试，多线程也会出现延迟执行的情况，和SpringBoot版本有关系，测试2.7.6有问题，2.0.9.RELEASE无问题）

package com.example.demo.conf;

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.TimeUnit;
import static java.lang.Thread.sleep;

@Component
@EnableAsync        //开启多线程
public class SaticScheduleTask {
    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron1() {
        System.out.println("第1个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron2() {
        System.out.println("第2个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron3() {
        System.out.println("第3个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron4() {
        System.out.println("第4个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron5() {
        System.out.println("第5个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 1 * * ?")
    public void jobCron6() {
        System.out.println("第6个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron7() {
        System.out.println("第7个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 0 1 11 ?")
    public void jobCron8() {
        System.out.println("第8个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 2 * * ?")
    public void jobCron9() {
        System.out.println("第9个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron10() throws InterruptedException {
        System.out.println("第10个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(120);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT1M")
    public void jobCron11() throws InterruptedException {
        System.out.println("第11个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(120);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT20S")
    public void jobCron12() throws InterruptedException {
        System.out.println("第12个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(360);
    }

    @Async
    @Scheduled(cron = "0 55 10 * * ?")
    public void jobCron13() {
        System.out.println("第13个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }

}

结果：按指定时间执行了，并没有受到其他比较耗时的任务影响

SpringBoot定时任务 @Scheduled 没有准时执行的原因及解决方案_Async_02

方法二（推荐）：改为线程池

下面的代码提供了一个线程池大小为13的taskScheduler

package com.example.demo.conf;

import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;

@Configuration
public class ScheduledTaskConfiguration implements SchedulingConfigurer {

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        final ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
        taskScheduler.setPoolSize(13);
        taskScheduler.initialize();
        taskRegistrar.setTaskScheduler(taskScheduler);
    }

}

package com.example.demo.conf;

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.TimeUnit;
import static java.lang.Thread.sleep;

@Component
//@EnableAsync        //开启多线程
public class SaticScheduleTask {
    private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron1() {
        System.out.println("第1个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron2() {
        System.out.println("第2个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron3() {
        System.out.println("第3个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron4() {
        System.out.println("第4个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 */10 * * * ?")
    public void jobCron5() {
        System.out.println("第5个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 1 * * ?")
    public void jobCron6() {
        System.out.println("第6个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron7() {
        System.out.println("第7个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 0 1 11 ?")
    public void jobCron8() {
        System.out.println("第8个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
    }

    @Async
    @Scheduled(cron = "0 0 2 * * ?")
    public void jobCron9() {
        System.out.println("第9个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT30S")
    public void jobCron10() throws InterruptedException {
        System.out.println("第10个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(120);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT1M")
    public void jobCron11() throws InterruptedException {
        System.out.println("第11个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(120);
    }
    @Async
    @Scheduled(initialDelayString = "PT1M", fixedDelayString = "PT20S")
    public void jobCron12() throws InterruptedException {
        System.out.println("第12个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());
        TimeUnit.SECONDS.sleep(360);
    }

    @Async
    @Scheduled(cron = "0 05 11 * * ?")
    public void jobCron13() {
        System.out.println("第13个定时任务开始 : " + LocalDateTime.now().format(FORMATTER) + "      线程 : " + Thread.currentThread().getName());

    }

}

结果：按指定时间执行了，并没有受到其他比较耗时的任务影响

SpringBoot定时任务 @Scheduled 没有准时执行的原因及解决方案_Async_03

附：分析 `@Scheduled 注解的源码`

/**
        * <p>Processing of {@code @Scheduled} annotations is performed by
 * registering a {@link ScheduledAnnotationBeanPostProcessor}. This can be
 * done manually or, more conveniently, through the {@code <task:annotation-driven/>}
 * element or @{@link EnableScheduling} annotation.
 */

每一个有 @Scheduled 注解的方法都会被注册为一个ScheduledAnnotationBeanPostProcessor, 再接着往下看ScheduledAnnotationBeanPostProcessor:

/**
 * Set the {@link org.springframework.scheduling.TaskScheduler} that will invoke
 * the scheduled methods, or a {@link java.util.concurrent.ScheduledExecutorService}
 * to be wrapped as a TaskScheduler.
 * <p>If not specified, default scheduler resolution will apply: searching for a
 * unique {@link TaskScheduler} bean in the context, or for a {@link TaskScheduler}
 * bean named "taskScheduler" otherwise; the same lookup will also be performed for
 * a {@link ScheduledExecutorService} bean. If neither of the two is resolvable,
 * a local single-threaded default scheduler will be created within the registrar.
 * @see #DEFAULT_TASK_SCHEDULER_BEAN_NAME
 */
public void setScheduler(Object scheduler) {
    this.scheduler = scheduler;
}

重点来了, 注意这句话:

If neither of the two is resolvable,a local single-threaded default scheduler will be created within the registrar.

这句话意味着, 如果我们不主动配置我们需要的 TaskScheduler, SpringBoot 会默认使用一个单线程的scheduler来处理我们用 @Scheduled 注解实现的定时任务

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