java - 让主线程等待，直到新的单线程在java中完全执行

Question

调度程序通过新的单线程从服务器获取配置。但即使调度程序正在执行 config() 以从服务器获取配置，应用程序也会继续执行。

App{
    XXXX;
    XXXX;
    try{
       scheduler()
    } catch(Exception e){

}

public void scheduler(){

ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();

        Callable<Void> callable = new Callable<Void>() {
            public Void call() throws Exception {
                try {
                    config();
                } finally {
                   service.schedule(this, TimeOut(), TimeUnit.SECONDS);
                }

                return null;

            }

        };
        service.schedule(callable, 0, TimeUnit.SECONDS);


}

如何让主线程等待，直到单线程获取配置完成。

Answer 1

在触发 ExecutorService#shutdown() 后尝试使用 ExecutorService#awaitTermination(time, unit):

ExecutorService#awaitTermination() blocks until all tasks have completed execution after a shutdown request, or the timeout occurs, or the current thread is interrupted, whichever happens first.

service.shutdown();
try {
    // Use Long.MAX_VALUE to wait forever, see link below
    service.awaitTermination(Long.MAX_VALUE, TimeUnit.NANOSECONDS);
} catch (InterruptedException e) {
    // TODO ...
}

ExecutorService#awaitTermination()

Timing