Springboot中如何自定义任务定时器

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-parent</artifactId>
        <version>2.0.0.RELEASE</version>
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>

   </dependencies>

启动配置类中加入@EnableScheduling注解，意思是开启定时任务。

@SpringBootApplication
@EnableScheduling
public class SpringbootExcelApplication {
          
   
    public static void main(String[] args) {
          
   
        SpringApplication.run(SpringbootExcelApplication.class, args);
    }

}

只定义一个任务时

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.util.Date;
@Component
public class ScheduleTask {
          
   
    @Scheduled(cron = "*/1 * * * * ?")
    public void execute1(){
          
   
        System.out.println(Thread.currentThread().getName()+"任务2每隔1s就执行");
    }
}

执行结果如下： 当任务执行时间比定时周期要长时：

@Scheduled(cron = "*/1 * * * * ?")
    public void execute1(){
          
   
        System.out.println(new Date());
        try {
          
   
            Thread.sleep(6000);
            System.out.println(Thread.currentThread().getName()+"任务1每隔1min就执行");
        } catch (InterruptedException e) {
          
   
            e.printStackTrace();
        }
    }

执行结果：

多任务时

@Component
public class ScheduleTask {
          
   
    @Scheduled(cron = "0 0/1 * * * ?")
    public void execute1() throws InterruptedException {
          
   
        System.out.println(new Date());
        //任务1每次执行花6s种
        Thread.sleep(6000);
        System.out.println(Thread.currentThread().getName()+"任务1每隔1min就执行");
    }
    @Scheduled(cron = "0 0/1 * * * ?")
    public void execute2(){
          
   
        System.out.println(new Date());
        System.out.println(Thread.currentThread().getName()+"任务2每隔1min就执行");
    }
}

执行结果：可以看出任务一和任务二都是在同一线程下执行的，任务一执行完成后，在执行任务二，这与我们期望的不一样。所以多任务执行时，需要开启多线程。

Mon Jan 18 16:15:00 CST 2021
scheduling-1任务1每隔1min就执行
Mon Jan 18 16:15:06 CST 2021
scheduling-1任务2每隔1min就执行
Mon Jan 18 16:16:00 CST 2021
scheduling-1任务1每隔1min就执行
Mon Jan 18 16:16:06 CST 2021
scheduling-1任务2每隔1min就执行

开启多线程后： 定义一个配置类开启多线程：

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

import java.util.concurrent.Executors;
@Configuration
public class ScheduleConfig implements SchedulingConfigurer {
          
   
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
          
   
        scheduledTaskRegistrar.setScheduler(Executors.newScheduledThreadPool(3));
    }
}

执行结果：

Mon Jan 18 16:22:00 CST 2021
Mon Jan 18 16:22:00 CST 2021
pool-1-thread-2任务2每隔1min就执行
pool-1-thread-1任务1每隔1min就执行
Mon Jan 18 16:23:00 CST 2021
pool-1-thread-3任务2每隔1min就执行
Mon Jan 18 16:23:00 CST 2021
pool-1-thread-1任务1每隔1min就执行

https://www.bejson.com/othertools/cron/