Scala:如何在子线程中捕获异常

Question

我原以为Try捕获跨线程异常，如下例所示。我想不是:那么如何在生成的子线程中捕获异常？

// Simple class that throws error
class Child extends Runnable {
  def run {
    val exception: Exception = new Exception("Foo")
    val i = 1
    Thread.sleep(1000)
    val lines = scala.io.Source.fromFile("/tmp/filefoobar.txt").mkString
    Thread.sleep(1000)
  }
}
// spawn the class above
def Parent() = {
  val doit = Try {
    val t = new Thread(new Child)
    t.start
    t.join()
  }

  doit match {
    case Success(v) => println("uh oh did not capture error")
    case Failure(v) => println("good we caught the error")
  }
}

输出
Scala> 父()

Exception in thread "Thread-35" java.io.FileNotFoundException: /tmp/filefoobar.txt (No such file or directory)
    at java.io.FileInputStream.open0(Native Method)
    at java.io.FileInputStream.open(FileInputStream.java:195)
    at java.io.FileInputStream.<init>(FileInputStream.java:138)
    at scala.io.Source$.fromFile(Source.scala:91)
    at scala.io.Source$.fromFile(Source.scala:76)
    at scala.io.Source$.fromFile(Source.scala:54)
    at $line120.$read$$iw$$iw$Child.run(<console>:16)
    at java.lang.Thread.run(Thread.java:745)
uh oh did not capture error

Answer 1

考虑使用 Futures 来处理异步任务的结果

import ExecutionContext.Implicits.global
val resultFuture: Future[Unit] = Future { new Child.run }
resultFuture.onComplete (result: Try[Unit] => ...)