Scala Try Catch Finally:
在Java中返回值优先级顺序:finally最高, try,catch 选其一,try中抛异常,返回catch,不抛异常,返回try,。
public class ExceptionDemo { public static void main(String[] args) { System.out.println(callMD()); } public static int callMD() { try { // throw new Exception(); return 1; } catch (Exception e) { return 2; } finally { return 3; } } }
Scala模仿Java:
object ExceptionCatchDemo extends App { def testTryCatchFinally: Int = { try { throw new Exception();} catch { case _ => return 2 } finally { return 3 } } println(testTryCatchFinally) }
运行结果:3
在Scala中返回值优先级顺序:try,catch 选其一,try中抛异常,返回catch,不抛异常,返回try,finally最低
补充: 从scala语言规范来看,try-catch-finally
表达式也是有返回值的,且返回值主要是取决于try
和catch
里的最后一行表达式,而finally
被认为是做一些收尾的工作的,不应该在里面去改变返回结果。编译器在finally
块最后自行增加了一个返回Unit
类型的值()
,编译器认为finally
块里的逻辑是一个“procedure”,一定要满足Unit
。
object ExceptionCatchDemo extends App { def testTryCatchFinally: Int = { try { throw new Exception() } catch { case _ => 2 } finally { 3 } } println(testTryCatchFinally) }
运行结果:2