Scala：默默地捕捉所有异常
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Scala: Silently catch all exceptions
提问by tmporaries
Empty catch block seems to be invalid in Scala
空的 catch 块在 Scala 中似乎无效
try {
func()
} catch {
} // error: illegal start of simple expression
How I can catch all exceptions without their processing?
我如何在没有处理的情况下捕获所有异常？
回答by Rex Kerr
Some exceptions really aren't meant to be caught. You can request it anyway:
有些异常真的不应该被捕获。您无论如何都可以请求它：
try { f(x) }
catch { case _: Throwable => }
but that's maybe not so safe.
但这可能不太安全。
All the safe exceptions are matched by scala.util.control.NonFatal, so you can:
所有安全异常都由 匹配scala.util.control.NonFatal，因此您可以：
import scala.util.control.NonFatal
try { f(x) }
catch { case NonFatal(t) => }
for a slightly less risky but still very useful catch.
对于风险稍低但仍然非常有用的捕获。
Or scala.util.Trycan do it for you:
或者scala.util.Try可以为您做：
Try { f(x) }
and you can pattern match on the result if you want to know what happened. (Trydoesn't work so well when you want a finallyblock, however.)
如果你想知道发生了什么，你可以对结果进行模式匹配。（但是，Try当您想要一个finally块时，效果不佳。）
回答by elm
In
在
import scala.util.Try
val res = Try (func()) toOption
if the Try is successful you will get a Some(value), if it fails a None.
如果 Try 成功，您将获得Some(value)，如果失败则为None。
回答by Akos Krivachy
Inside of Scala's catch block you need to use similar construct as in a match statement:
在 Scala 的 catch 块中，您需要使用与 match 语句中类似的构造：
try {
func()
} catch {
case _: Throwable => // Catching all exceptions and not doing anything with them
}
回答by Tamere
Try adding
尝试添加
case x =>
in your catch block :)
在您的 catch 块中 :)
回答by som-snytt
If annotating with Throwable is burdensome, you can also
如果用 Throwable 注释很麻烦，你也可以
scala> def quietly[A]: PartialFunction[Throwable, A] = { case _ => null.asInstanceOf[A] }
quietly: [A]=> PartialFunction[Throwable,A]
scala> val x: String = try { ??? } catch quietly
x: String = null
which has the small virtual of being self-documenting.
它具有自我记录的小虚拟。
scala> val y = try { throw new NullPointerException ; () } catch quietly
y: Unit = ()
回答by om-nom-nom
Just for a sake of completeness, there is a set of built-in methods in Exception, including silently catching exceptions. See Using scala.util.control.Exceptionfor details on usage.
为了完整起见，Exception 中有一组内置方法，包括静默捕获异常。有关用法的详细信息，请参阅使用 scala.util.control.Exception。
回答by Johnny
I like one of the suggestions here to use Try()with toOption, but in case you don't want to go further with Option, you can just do:
我喜欢这里使用Try()with的建议之一toOption，但如果您不想进一步使用 Option，您可以这样做：
Try(func()) match {
case Success(answer) => continue(answer)
case Failure(e) => //do nothing
}
回答by leo9r
What about:
关于什么：
import scala.util.control.Exception.catching
catching(classOf[Any]) opt {func()}
It generates an Option like in some of the previous answers.
它会生成一个 Option 就像之前的一些答案一样。
