Scala - futures不运行 [英] Scala - futures does not run

问题描述

我试图运行以下未来的基本代码

I am trying to run the following future basic code

 future { println("ssss")} onSuccess{ case _ => println("succ")}

$ b $ p

然而，当我运行main方法时，打印，系统几乎立即退出。我使用隐式ExecutionContext。任何提示？

However, when I run the main method, nothing to the console is printed and the system exits almost instantly. I am using the implicit ExecutionContext. Any hints?

此代码：

  val f = future(Await.ready(Promise().future, d.timeLeft))

   f.onSuccess {
     case _ => println("hee")
   }

>

推荐答案

期货在专用线程池上执行。如果你的主程序不等待未来，它将立即退出，未来将没有机会执行。
这里可以做的是在主程序中使用 Await 阻塞主线程，直到将来执行：

Futures are executed on a dedicated thread pool. If your main program does not wait for the future, it will exit immediately and the future won't have a chance to execute. What you can do here is to use Await in your main program to block the main thread until the future executes:

def main( args: Array[String] ) {
  val fut = future { println("ssss")}
  fut onSuccess{ case _ => println("succ")}
  Await.result( fut )
}

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