Springboot timed task @Scheduled use

Springboot timed task @Scheduled use

Scheduled is not suitable for dynamically modifying the frequency. If you want to dynamically modify the frequency, please refer to:
Springboot2.x integrated quartz to achieve dynamic timing tasks

1. Add @EnableScheduling to the startup class to start timing tasks

@SpringBootApplication
@EnableScheduling
@Slf4j
public class MaintainStarter {
    
    
    public static void main(String[] args) {
    
    
        SpringApplication.run(MaintainStarter.class, args);
    }
}

2. Create a thread pool

@Configuration
@EnableAsync
public class ThreadPoolTaskConfig {
    
    
    private static final int CORE_POOL_SIZE = Runtime.getRuntime().availableProcessors() * 2;
    private static final int MAX_POOL_SIZE = Math.max(CORE_POOL_SIZE * 4, 256);
    private static final int KEEP_ALIVE_TIME = 10; //允许线程空闲时间（单位为秒）
    private static final int QUEUE_CAPACITY = 200; // 缓冲队列数
    private static final int AWAIT_TERMINATION = 60;//线程池中任务的等待时间，如果超过这个时候还没有销毁就强制销毁
    private static final Boolean WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN = true;//用来设置线程池关闭的时候等待所有任务都完成再继续销毁其他的Bean


    @Bean("logTaskExecutor")
    public ThreadPoolTaskExecutor logTaskExecutor() {
    
    
        return getThreadPoolTaskExecutor("log-thread-");
    }

    @Bean("schedulingTaskExecutor")
    public ThreadPoolTaskExecutor schedulingTaskExecutor() {
    
    
        return getThreadPoolTaskExecutor("scheduling-thread");
    }

    private ThreadPoolTaskExecutor getThreadPoolTaskExecutor(String s) {
    
    
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setCorePoolSize(CORE_POOL_SIZE);
        taskExecutor.setMaxPoolSize(MAX_POOL_SIZE);
        taskExecutor.setKeepAliveSeconds(KEEP_ALIVE_TIME);
        taskExecutor.setQueueCapacity(QUEUE_CAPACITY);
        taskExecutor.setThreadNamePrefix(s);
        taskExecutor.setWaitForTasksToCompleteOnShutdown(WAIT_FOR_TASKS_TO_COMPLETE_ON_SHUTDOWN);
        taskExecutor.setAwaitTerminationSeconds(AWAIT_TERMINATION);
        taskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        taskExecutor.initialize();
        return taskExecutor;
    }

}

3. Use @Scheduled

@Slf4j
@Component
public class SystemScheduling {
    
    

    /**
     * 定时任务例子
     */
    @Async("schedulingTaskExecutor")
    @Scheduled(cron = CronConstant.ONE_HOUR)
    public void logging() throws MalformedObjectNameException, InstanceNotFoundException, ReflectionException {
    
    
        log.info("SystemScheduling = now : [{}] memory : [{}] cpu : [{}]", new Date(), Runtime.getRuntime().totalMemory() / (1024 * 1024) + "M", getCpu());
    }

    private int getCpu() throws MalformedObjectNameException, ReflectionException, InstanceNotFoundException {
    
    
        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        ObjectName name = ObjectName.getInstance("java.lang:type=OperatingSystem");
        AttributeList list = mbs.getAttributes(name, new String[]{
    
    "ProcessCpuLoad"});
        if (list.isEmpty()) return 0;
        Attribute att = (Attribute) list.get(0);
        Double value = (Double) att.getValue();
        if (value == -1.0) return 0;
        return (int) ((int) (value * 1000) / 10.0);
    }
}

public class CronConstant {
    
    
    /**
     * 每小时执行一次
     */
    public static final String ONE_HOUR = "0 0 0/1 * * ? ";
}

As for the corresponding Cron expression, it can be generated through https://cron.qqe2.com

Scheduled parameter description:

1. cron: expression, specify the task to be executed at a specific time;
2. fixedDelay: indicate how long to execute the task again after the completion of the last task execution, the parameter type is long, the unit is ms;
3. fixedDelayString: the meaning is the same as fixedDelay, Only the parameter type becomes String;
4.fixedRate: indicates that the task is executed at a certain frequency, that is, the time interval between each start is the same, the parameter type is long, the unit is ms;
5.fixedRateString: has the same meaning as fixedRate, but the parameter The type is changed to String;
6.initialDelay: indicates how long to delay the task to be executed for the first time, the parameter type is long, the unit is ms;
7.initialDelayString: the meaning is the same as initialDelay, but the parameter type is changed to String;
8.zone: time zone , The default is the current time zone.