Java ScheduledExecutorService 定期运行

Question

我正在尝试每分钟运行一个作业[其中包含 3 个应并行运行的服务]。下面是我的代码片段。

ExecutorService service = Executors.newFixedThreadPool(servicesMap.size());
for (Map.Entry entry : servicesMap.entrySet()) {
    service.submit(new MyService(conn, serviceID)); 
   // here serviceID is id1 id2 id3 these three job should execute parallel
}

注意:MyTask 实现 Callable & servicesMap 将始终为 3

如果我尝试使用 ScheduledExecutorService 那么我无法实现它。它说scheduleService.schedule不接受Callable类型参数

ScheduledExecutorService scheduleService = Executors.newScheduledThreadPool(servicesMap.size());
for (Map.Entry entry : servicesMap.entrySet()) {
    scheduleService.schedule((new MyService(conn, serviceID)), 0, 60, TimeUnit.SECONDS);
}

请帮助修改 ScheduledExecutorService 代码以实现此目的。

Answer 1

您的 schedule(…) 调用包含的参数多于 the method有参数。

不过，我不确定你到底想要什么。如果您想在未来一分钟内运行您的服务，请使用以下调用:

scheduleService.schedule(new MyService(conn, serviceID), 60, TimeUnit.SECONDS);

如果您希望每分钟运行一次服务(立即开始)，则使用以下两个调用之一:

scheduleService.scheduleAtFixedRate(new MyService(conn, serviceID), 0, 60, TimeUnit.SECONDS);
scheduleService.scheduleWithFixedDelay(new MyService(conn, serviceID), 0, 60, TimeUnit.SECONDS);

<小时/>

关于评论中的后续问题:

How to make, within a minute Service1 Service2 Service3 should run parallel, then next minute do the same.

ScheduledExecutorService scheduleService = …;
Collection<Callable<Void>> services = …;
Runnable svcRunner = new Runnable() {
    @Override
    public void run() {
        Collection<Future<Void>> futures = new ArrayList<>(services.size());
        // start all services in parallel
        for (Callable<Void> service : services) {
            // any ExecutorService would do here, i.e., doesn't have to be a
            // ScheduledExecutorService
            futures.add(scheduleService.submit(service));
        }
        // wait for all services to complete
        for (Future<Void> future : futures) {
            try {
                future.get();
            } catch (InterruptedException | ExecutionException e) {
                // TODO do something meaningful
            }
        }
    }
};
// run the scheduler every minute (i.e., one minute after the last service
// has finished), starting now
scheduleService.scheduleWithFixedDelay(svcRunner, 0, 60, TimeUnit.SECONDS);

为了简单起见，我将服务存储在一个集合中。如果需要，您还可以每次重新创建它们。