Observable是否在RxJava中默認在計算線程上運行

Question

目前，我正在學習RxJava ，只是陷入了一個基本的疑問。 請參見下面的代碼。 我沒有使用任何subscribeOn() 。 以下代碼將在主線程還是在計算線程上執行？

import io.reactivex.Observable;
import java.util.concurrent.TimeUnit;

public class Launcher {
      public static void main(String[] args) {
        Observable<Long> secondIntervals =
          Observable.interval(1, TimeUnit.SECONDS);

        secondIntervals.subscribe(s -> System.out.println(s));

        /* Hold main thread for 5 seconds
        so Observable above has chance to fire */
        sleep(5000);
      }

      public static void sleep(long millis) {
        try {
          Thread.sleep(millis);
        } catch (InterruptedException e) {
          e.printStackTrace();
        }
      }
}

Answer 1

它將在計算線程上執行，請參見main方法的以下修改版本：

public static void main(String[] args) {
    Observable<Long> secondIntervals =
            Observable.interval(1, TimeUnit.SECONDS);

    secondIntervals.subscribe(s -> System.out.println("Observable thread id: "
                                                      + Thread.currentThread().getId()));

    System.out.println("Main thread id: " + Thread.currentThread().getId());

    /* Hold main thread for 5 seconds
    so Observable above has chance to fire */
    sleep(5000);
}