Scala Try 和不同的失败案例

Question

此代码作为异常(exception)返回“我失败了”。

  Try({
    throw new Exception()
  }) match {
    case Failure(e) => println("I've failed")
    case Success(s) => println("I've succeeded")
  }

但是如果我有不同的异常怎么办，例如:

  Try({
    if(someBoolean) {
      throw new DifferentException()
    } else {
      throw new Exception()
    }
  }) match {
    case Failure(e) => println("I've failed")
    case Success(s) => println("I've succeeded")
  }

如何更改匹配语句，以便我们对 Exception 和 DifferentException 有不同的情况？

我知道我可以做到:

  Try({
    if(true) {
      throw new DifferentException()
    } else {
      throw new Exception()
    }
  }) match {
    case Failure(e) if e.isInstanceOf[DifferentException] => println("I've failed differently")
    case Failure(e) if e.isInstanceOf[Exception]          => println("I've failed")
    case Success(s) => println("I've succeeded")
  }

这是最好的，即最不冗长的方式吗？

[编辑]

感谢 Ashesh。对我来说，最不冗长的是:

case class DifferentException() extends Exception() {}

Try({
  if(someBoolean) { 
    throw new DifferentException
  } else { 
    throw new Exception
  } 
}) match { 
  case Failure(DifferentException()) => println("I've failed differently")
  case Failure(e)                    => println("I've failed")
  case Success(s)                    => println("I've succeeded")
}

Answer 1

您可以为任何异常类型(无论是否为案例类)匹配Failure(e: ExceptionType)，无需创建您自己的异常类型或两个模式匹配表达式:

def printResult(action: => Unit) = {
  Try(action) match {
    case Failure(e: IllegalArgumentException) => println("illegal arg exception")
    case Failure(e) => println("other exception")
    case _ => println("success")
  }
}

printResult(throw new IllegalArgumentException)  // prints "illegal arg exception"
printResult(throw new RuntimeException)          // prints "other exception"
printResult(1)                                   // prints "success"