在捕获多个Java异常时，如何在不编写重复代码的情况下添加状态信息？(How do I add state information without writing repetitive code wh

在捕获多个Java异常时，如何在不编写重复代码的情况下添加状态信息？(How do I add state information without writing repetitive code when catching multiple Java exceptions?)

我已经阅读了其他一些关于避免Java catch块重复的帖子。 显然，我真正想要的是“多捕获”，但看到Java 7还没有到来，是否有一个很好的模式让我添加状态到我的异常，然后重新抛出它们，而不是抓住厨房水槽 ？

具体来说，我有一些代码可以进行库调用，它可以抛出异常，但是没有为成功的调试提供足够的上下文。 我发现自己遇到了问题，然后进入，将库调用包装在try / catch中，捕获特定的异常，然后在catch块中添加额外的状态信息并重新抛出捕获的异常。 然后，我一遍又一遍地重复遍历该循环，每次都找到一个新的错误条件来记录。 我结束了

try { make_library_call(); } catch (SomeException e){ throw new SomeException ("Needed local state information is " + importantInfo, e); } catch (SomeOtherException e){ throw new SomeOtherException ("Needed local state information is " + importantInfo, e); } catch (YetAnotherException e){ throw new YetAnotherException ("Needed local state information is " + importantInfo, e); }

我认为我真正希望看到的更多的是

try { make_lib_call(); } catch(Exception e){ e.AddSomeInformationSomehow("Needed Info" + importantInfo); throw e; }

假设在那种情况下， e会在重新抛出时保持其实际运行时类型 - 在这种情况下，即使捕获未选中也可能是正常的，因为我将重新抛出它们，并且它们将受益于携带额外的状态信息同样。 我猜一个替代品可能是这样的

try{ make_lib_call(); } finally { if (/*an exception happened*/) logger.debug("Some state info: " + importantInfo); }

但我不知道怎么写条件。 那是疯了/错吗？

I've read a few other posts like this one about avoiding repetition in Java catch blocks. Apparently, what I really want is "multi-catch", but seeing as Java 7 isn't here yet, is there a good pattern to let me add state to my exceptions, then re-throw them, without catching the kitchen sink?

Specifically, I have some code that makes library calls, which can throw exceptions, but don't provide nearly enough context for successful debuging. I find myself having a problem, then going in, wrapping the library call in a try/catch, catching the specific exception, then adding extra state information in the catch block and re-throwing the caught exception. I then re-iterate through that loop over and over, each time finding a new error condition to log. I wind up with

try { make_library_call(); } catch (SomeException e){ throw new SomeException ("Needed local state information is " + importantInfo, e); } catch (SomeOtherException e){ throw new SomeOtherException ("Needed local state information is " + importantInfo, e); } catch (YetAnotherException e){ throw new YetAnotherException ("Needed local state information is " + importantInfo, e); }

etc etc. I think what I'd really like to see is more along the lines of

try { make_lib_call(); } catch(Exception e){ e.AddSomeInformationSomehow("Needed Info" + importantInfo); throw e; }

assuming that in that case e would keep its actual runtime type when re-thrown -- in this case, even catching unchecked would probably be OK since I'd be re-throwing them, and they'd benefit from carrying the extra state info as well. I guess an alternate might be something like

try{ make_lib_call(); } finally { if (/*an exception happened*/) logger.debug("Some state info: " + importantInfo); }

but I don't know how to write the conditional. Is that crazy / wrong?

最满意答案

你可能期待这个，但不 ，没有一个好的 （并且我的意思是干净的）方法来做到这一点。 你可能期待它，因为你下意识地知道，如果有一个很好的模式，这可能不值得添加到Java 7。

它实际上是最终的重新抛出功能，在这种情况下你会发现它非常方便。

You're probably expecting this, but no, there isn't a good (and by good I mean clean) way to do this. You're probably expecting it because you subconsciously knew that if there was a good pattern for doing this, it probably wouldn't have been worth adding to Java 7.

It's actually the final rethrow feature that you'd find really handy in this case.