scala技巧
catch, try, 异常

异常处理

文章目录

下面是一段异常处理的代码：

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try {
  println("start....")
  throw new RuntimeException
} catch {
  case re: RuntimeException => println("this is RuntimeException")
  case e: Exception => println("this is Exception")
}

scala中没有多重catch block。而是使用模式匹配来逐级匹配异常并进行处理。

看下执行结果：

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start....
this is RuntimeException

还可以catch Error：

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try {
  println("start....")
  throw new OutOfMemoryError()
} catch {
  case re: RuntimeException => println("this is RuntimeException")
  case e: Exception => println("this is Exception")
  case error: Error => println("this is an error")
}

结果如下：

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start....
this is an error

当然也可以捕捉Throwable，但是在模式匹配中使用通配符却是一个更好地选项：

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try {
  println("start....")
  throw new Throwable()
} catch {
  case re: RuntimeException => println("this is RuntimeException")
  case e: Exception => println("this is Exception")
  case error: Error => println("this is an error")
  case _ => println("We catched something.")
}

执行结果：

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start....
We catched something.