为什么这个cron模式不是每37秒匹配/运行一次?

我有一个具有以下属性的Spring应用程序:

cobra.tarifas.intervaloEntreCobrancas =*/37 * * * * *

这就是它的用途:

@Scheduled(cron = "${cobra.tarifas.intervaloEntreCobrancas}")
public void cobraTarifaDMaisZero() {

    int number = new Random().nextInt();

    System.out.println("started " + number + " at " + LocalTime.now().withNano(0));
    try {
        Thread.sleep(5000);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    System.out.println("finished " + number + " at " + LocalTime.now().withNano(0));
}

所以每次它运行时,我都会有一个日志,指出它的开始和结束时间,以及一个“唯一”标识符(Spring在运行时使用相同的实例) @Scheduled 没有额外配置的类, this.toString 每次返回相同的字符串)。每次执行需要5秒钟才能完成。

我以为cron的意思是“每37秒运行一次”,但事实并非如此。

* * * * * * 我知道了:

started -1615036471 at 10:18:46
finished -1615036471 at 10:18:51
started 2090620070 at 10:18:52
finished 2090620070 at 10:18:57
started -349207943 at 10:18:58
finished -349207943 at 10:19:03

这是有道理的:在前一次执行完成后,需要1s才能开始新的执行,总是需要5s才能完成。但当我用 */37 * * * * *

started -644623959 at 10:54
finished -644623959 at 10:54:05
started 212117957 at 10:54:37
finished 212117957 at 10:54:42
started 1788724609 at 10:55
finished 1788724609 at 10:55:05
started 362510867 at 10:55:37
finished 362510867 at 10:55:42
started -25103618 at 10:56
finished -25103618 at 10:56:05
started -820939074 at 10:56:37
finished -820939074 at 10:56:42

@fixedDelay 但在某些属性文件中可以灵活更改( @固定延迟 仅接受常量)。