捕获Future.failed错误

Question

以下代码打印2，但我希望（错误地）Future.failed充当Java throw new Exception，停止任何后续指令（并由recover捕获）。如何使此代码打印“错误消息”？

object HelloScala extends App {

      val f = futureFunction(1)
      f.map { result => println(result) }
      .recover { case e => println(e.getMessage) }


      def futureFunction (i:Int) =  {

            if (i==1) 
               Future.failed(new Throwable("error msg"))

           Future {2}
      }

      Thread.sleep(10000)
}

Answer 1

您的futureFunction将始终返回Future{2}。以下内容可能满足您的需求：

def futureFunction (i: Int) = {
  if (i==1) 
    Future.failed(new Throwable("error msg"))
  else
    Future.successful(2)
}