[Dart语法]第七章：异常处理

异常处理

throw

bool flag = false;
if (flag == false) {
    throw ('this is a wrong tips');
}
/*
Unhandled exception:
this is a wrong tips
#0      main (file:///d:/Flutter/dart_test/dart/dart3.dart:4:5)
#1      _startIsolate.<anonymous closure> (dart:isolate-patch/isolate_patch.dart:299:32)
#2      _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:168:12)
*/

try-catch

try {
  breedMoreLlamas();
} on OutOfLlamasException {
  // 一个特殊的异常
  buyMoreLlamas();
} on Exception catch (e) {
  // 其他任何异常
  print('Unknown exception: $e');
} catch (e) {
  // 没有指定的类型，处理所有异常
  print('Something really unknown: $e');
}

finally

//任何匹配的 catch 执行完成后，再执行 finally
try {
  breedMoreLlamas();
} catch (e) {
  print('Error: $e'); // Handle the exception first.
} finally {
  cleanLlamaStalls(); // Then clean up.
}