在Java(或任何其他带有受控异常的语言)中,当创建您自己的异常类时,您如何决定它应该被检查还是未检查?
我的直觉是,在调用者可能能够以某种有效的方式恢复的情况下,将调用checked异常,而作为未检查的异常则更多地用于不可恢复的情况,但我对其他人的想法感兴趣。
在Java(或任何其他带有受控异常的语言)中,当创建您自己的异常类时,您如何决定它应该被检查还是未检查?
我的直觉是,在调用者可能能够以某种有效的方式恢复的情况下,将调用checked异常,而作为未检查的异常则更多地用于不可恢复的情况,但我对其他人的想法感兴趣。
当前回答
我认为当声明应用程序异常时,它应该是未检查的异常,即RuntimeException的子类。 原因是它不会用try-catch和方法上的抛出声明使应用程序代码混乱。如果你的应用程序使用Java Api,抛出检查异常,无论如何都需要处理。对于其他情况,应用程序可以抛出未经检查的异常。如果应用程序调用方仍然需要处理未检查的异常,则可以这样做。
其他回答
来自Java学习者:
When an exception occurs, you have to either catch and handle the exception, or tell compiler that you can't handle it by declaring that your method throws that exception, then the code that uses your method will have to handle that exception (even it also may choose to declare that it throws the exception if it can't handle it). Compiler will check that we have done one of the two things (catch, or declare). So these are called Checked exceptions. But Errors, and Runtime Exceptions are not checked for by compiler (even though you can choose to catch, or declare, it is not required). So, these two are called Unchecked exceptions. Errors are used to represent those conditions which occur outside the application, such as crash of the system. Runtime exceptions are usually occur by fault in the application logic. You can't do anything in these situations. When runtime exception occur, you have to re-write your program code. So, these are not checked by compiler. These runtime exceptions will uncover in development, and testing period. Then we have to refactor our code to remove these errors.
以下是我在多年开发经验后的一些看法:
Checked exception. This is a part of business use case or call flow, this is a part of application logic we expect or not expect. For example connection rejected, condition is not satisfied etc. We need to handle it and show corresponding message to user with instructions what happened and what to do next (try again later etc). I usually call it post-processing exception or "user" exception. Unchecked exception. This is a part of programming exception, some mistake in software code programming (bug, defect) and reflects a way how programmers must use API as per documentation. If an external lib/framework doc says it expects to get data in some range and non null, because NPE or IllegalArgumentException will be thrown, programmer should expect it and use API correctly as per documentation. Otherwise the exception will be thrown. I usually call it pre-processing exception or "validation" exception.
目标受众。现在让我们来谈谈目标受众或设计例外的人群(根据我的观点):
检查异常。目标受众是用户/客户。 未经检查的异常。目标受众是开发人员。换句话说,未检查异常仅是为开发人员设计的。
通过应用程序开发生命周期阶段。
受控异常被设计为在整个生产生命周期中存在,作为应用程序处理异常情况的正常和预期机制。 未检查异常被设计为只存在于应用程序开发/测试生命周期期间,所有这些异常都应该在这段时间内得到修复,并且当应用程序已经在生产环境中运行时不应该抛出。
框架通常使用未检查异常(例如Spring)的原因是框架不能确定应用程序的业务逻辑,这取决于开发人员捕捉并设计自己的逻辑。
我使用的规则是:永远不要使用未经检查的异常!(或者当你看不到任何方法的时候)
从使用您的库的开发人员或使用您的库/应用程序的最终用户的角度来看,遇到由于不应出现的异常而导致应用程序崩溃的情况真的很糟糕。指望包罗万象也不行。
通过这种方式,最终用户仍然可以看到错误消息,而不是应用程序完全消失。
当你想要向调用者提供信息时,受控异常对于可恢复的情况很有用(例如,权限不足,文件未找到等)。
未检查异常很少用于在运行时通知用户或程序员严重错误或意外情况。如果你编写的代码或库将被其他人使用,不要抛出这些异常,因为他们可能不希望你的软件抛出未经检查的异常,因为编译器不会强制捕获或声明这些异常。
我同意将未检查异常作为规则的偏好,特别是在设计API时。调用方总是可以选择捕获记录在案的、未检查的异常。你只是没有必要强迫打电话的人。
I find checked exceptions useful at the lower-level, as implementation detail. It often seems like a better flow of control mechanism than having to manage a specified error "return code". It can sometimes help see the impact of an idea for a low level code change too... declare a checked exception downstream and see who would need to adjust. This last point doesn't apply if there are a lot of generic: catch(Exception e) or throws Exception which is usually not too well-thought out anyway.