SpringBoot最简单的定时任务@Scheduler的使用及解读

       <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>

@SpringBootApplication
//此注解开启异步定时任务,必须要有
@EnableScheduling
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

@Component
public class SpringJob {
    //springboot扫描到这个注解就会按照定义的计划去执行任务
    //cron是cron表达式,因为很简单但是描述要话费比较多的篇幅,所以略
    @Scheduled(cron = "0/1 * * * * ?")
    public void myJob(){
        //任务处理逻辑
        System.out.println(new Date() +"Spring Scheduler 执行");
    }
}

String cron() default ""; 
String zone() default "";
long fixedDelay() default -1;
String fixedDelayString() default "";
long fixedRate() default -1;
String fixedRateString() default "";
long initialDelay() default -1;
String initialDelayString() default "";

String cron() default “”;接收一个cron表达式字符串,以cron表达式调度任务
String zone() default “”;设置时区,不设置的话cron就基于服务器所在的本地时区
long fixedDelay() default -1;设置任务间隔时间(毫秒),就是任务结束后再过多久开始新的任务
String fixedDelayString() default “”;同 long fixedDelay(),只是把参数从long改成string
long fixedRate() default -1;设置任务每隔多久开启
String fixedRateString() default “”;同 long fixedRate() 只是把参数从long改成string
long initialDelay() default -1;第一次执行延迟时间(启动后多久才开始任务)
String initialDelayString() default “”;同 long initialDelay()

@Component
public class SpringJob {

    @Scheduled(fixedRateString = "1000")
    public void myJob2() throws InterruptedException {
        System.out.println(new Date() +" job开启");
        Thread.sleep(2000);
        System.out.println(new Date() +" job结束");
    }
}

执行结果:
Fri Jul 31 10:34:16 CST 2020 job开启
Fri Jul 31 10:34:18 CST 2020 job结束
Fri Jul 31 10:34:18 CST 2020 job开启
Fri Jul 31 10:34:20 CST 2020 job结束
Fri Jul 31 10:34:20 CST 2020 job开启
Fri Jul 31 10:34:22 CST 2020 job结束
Fri Jul 31 10:34:22 CST 2020 job开启
Fri Jul 31 10:34:24 CST 2020 job结束
Fri Jul 31 10:34:24 CST 2020 job开启
Fri Jul 31 10:34:26 CST 2020 job结束
Fri Jul 31 10:34:26 CST 2020 job开启
Fri Jul 31 10:34:28 CST 2020 job结束
Fri Jul 31 10:34:28 CST 2020 job开启
Fri Jul 31 10:34:30 CST 2020 job结束

@Component
public class SpringJob {
    @Scheduled(fixedRateString  = "2000")
    public void myJob() throws InterruptedException {
        System.out.println(new Date() +" job1开始");
        Thread.sleep(10000);
        System.out.println(new Date() +" job1结束");
    }
    @Scheduled(fixedRateString = "1000")
    public void myJob2() throws InterruptedException {
        System.out.println(new Date() +" job2开启");
        Thread.sleep(2000);
        System.out.println(new Date() +" job2结束");
    }
}
执行结果:
Fri Jul 31 10:51:56 CST 2020 job1开始
Fri Jul 31 10:52:06 CST 2020 job1结束
Fri Jul 31 10:52:06 CST 2020 job2开启
Fri Jul 31 10:52:08 CST 2020 job2结束
Fri Jul 31 10:52:08 CST 2020 job2开启
Fri Jul 31 10:52:10 CST 2020 job2结束
Fri Jul 31 10:52:10 CST 2020 job1开始
Fri Jul 31 10:52:20 CST 2020 job1结束
Fri Jul 31 10:52:20 CST 2020 job2开启
Fri Jul 31 10:52:22 CST 2020 job2结束
Fri Jul 31 10:52:22 CST 2020 job2开启
Fri Jul 31 10:52:24 CST 2020 job2结束

@Configuration
public class ScheduleConfig implements SchedulingConfigurer {
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.setScheduler(setExecutor());
    }
    @Bean
    public Executor setExecutor() {
        //设置线程个数,这里我们设置5个(同一时间可以并行执行5个线程)
        return Executors.newScheduledThreadPool(5);
    }
}

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

@Component
public class SpringJob {
    @Async   
    @Scheduled(fixedRateString = "2000")
    public void myJob() throws InterruptedException {
        System.out.println(new Date() + " job1开始");
        Thread.sleep(10000);
        System.out.println(new Date() + " job1结束");
    }
    
    @Scheduled(fixedRateString = "1000")
    public void myJob2() throws InterruptedException {
        System.out.println(new Date() + " job2开启");
        Thread.sleep(2000);
        System.out.println(new Date() + " job2结束");
    }
}
执行结果:
Fri Jul 31 11:08:57 CST 2020 job2开启
Fri Jul 31 11:08:57 CST 2020 job1开始
Fri Jul 31 11:08:59 CST 2020 job1开始
Fri Jul 31 11:08:59 CST 2020 job2结束
Fri Jul 31 11:08:59 CST 2020 job2开启
Fri Jul 31 11:09:01 CST 2020 job1开始
Fri Jul 31 11:09:01 CST 2020 job2结束
Fri Jul 31 11:09:01 CST 2020 job2开启
Fri Jul 31 11:09:03 CST 2020 job1开始
Fri Jul 31 11:09:03 CST 2020 job2结束
Fri Jul 31 11:09:03 CST 2020 job2开启