Question

我对异常泄漏有疑问。

 case class CustomException(message: String) extends RuntimeException(message)

   def listOfFut(list: List[Int]): Future[List[Int]] = {
          def handleFut(list: List[Int]): Future[List[Int]] = {
            if (list.isEmpty) throw CustomException("Test")
            else Future.successful(list)
          }
          for {
            myList <- Future.successful(list)
            result <- handleFut(myList)
          } yield result
        }

我做了同样的事情，比如上面的片段，但得到的反馈可能会泄漏异常而不包装它。基本上，throw CustomException("Test")可能会泄漏异常。

Answer 1

首先，我没有看到任何异常泄漏的情况，就好像列表为空，它会因自定义异常而异常终止。您可以遵循的方法之一是使用Either将事件包装在Left中，将正确的输出包装在Right中。

但这将涉及更改方法签名

def listOfFut(list: List[Int]): Future[Either[Exception,List[Int]]] = {

  def handleFut(list: List[Int]): Future[Either[Exception,List[Int]]] = {
    if (list.isEmpty) Future.successful(Left(CustomException("Test")))
    else Future.successful(Right(list))
  }

  for {
    myList <- Future.successful(list)
    result <- handleFut(myList)
  } yield result
}

listOfFut(List()) onComplete {
  case Success(value) => println(s"Got the callback, meaning = $value")
    value match {
      case Right(output) =>
        println(s"Output is ${output}")
      case Left(ex) =>
        println(s"Exception is ${ex}")
    }
  case Failure(e) => e.printStackTrace
}

如果这回答了你的问题，请告诉我。

Answer 2

对def handleFut(list: List[Int]): Future[Either[Exception,List[Int]]] = { if (list.isEmpty) Future.failed(new CustomException("Test")) else Future.successful(Right(list)) }的回答是处理异常而不是抛出异常。你应该失败的未来：

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发生例外泄漏

2 个答案: