@Scheduled属性

@Scheduled属性

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//
package org.springframework.scheduling.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;

@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(Schedules.class)
public @interface Scheduled {
    String CRON_DISABLED = "-";
    String cron() default "";
    String zone() default "";
    // 上一次任务执行结束开始计时
    long fixedDelay() default -1L;
    String fixedDelayString() default "";
    // 上一次任务开始的时候开始计时 比如5*1000. 上一次任务开始后5秒就继续执行定时任务
    long fixedRate() default -1L;
    String fixedRateString() default "";
    long initialDelay() default -1L;
    String initialDelayString() default "";
    TimeUnit timeUnit() default TimeUnit.MILLISECONDS;
}

/* 
测试案例
1\未开启多线程模式 会导致每5秒定时执行的线程任务发生阻塞，线程任务之间时间间隔不为5s
2\注释开启多线程模式，线程池避免线程频繁创建和销毁。但是一旦线程任务大于线程池的线程数，也会造成阻塞
*/
@Configuration
@EnableScheduling
@EnableAsync
public class ScheduleTask {
    
    private AtomicInteger number = new AtomicInteger();
    
    @Async // 开启异步
    @Scheduled(fixedRate = 5000 )
    public void job(){
        LocalTime start = LocalTime.now();
        //前面和末尾几个字符串是用来改变打印的颜色的
        System.out.println("\033[31;4m" + Thread.currentThread() + " start " + number.incrementAndGet()
                + " @ " + start + "\033[0m");
        try {
            Thread.sleep(ThreadLocalRandom.current().nextInt(15)*1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        LocalTime end = LocalTime.now();
        System.out.println(Thread.currentThread() + " end " + number.get() + " @ "+
                end + ", seconds cost "+ (ChronoUnit.SECONDS.between(start, end)));

    }

    @Bean
    public TaskScheduler taskScheduler() {
        ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
        taskScheduler.setPoolSize(10);
        return taskScheduler;
    }
}

参考博客：https://blog.csdn.net/czx2018/article/details/83501945