在objective-c/cocoa中抛出异常的最佳方法是什么?
当前回答
我认为为了保持一致性,最好在你自己的类中使用@throw,它扩展了NSException。然后使用相同的表示法try catch finally:
@try {
.....
}
@catch{
...
}
@finally{
...
}
Apple解释了如何抛出和处理异常:
捕获异常 抛出异常
其他回答
我认为为了保持一致性,最好在你自己的类中使用@throw,它扩展了NSException。然后使用相同的表示法try catch finally:
@try {
.....
}
@catch{
...
}
@finally{
...
}
Apple解释了如何抛出和处理异常:
捕获异常 抛出异常
@throw([NSException exceptionWith…])
Xcode将@throw语句识别为函数出口点,就像return语句一样。使用@throw语法可以避免错误的“Control may reach end of non-void function”警告,你可能会从[NSException raise:…]得到这种警告。
同样,@throw也可以用来抛出不属于NSException类的对象。
我认为你永远不应该使用异常来控制正常的程序流程。但是,当某些值与所需值不匹配时,应该抛出异常。
例如,如果某个函数接受一个值,并且该值永远不允许为nil,那么就可以抛出一个异常,而不是尝试做一些“聪明”的事情……
Ries
使用NSError来传达失败而不是异常。
关于NSError的一些要点:
NSError allows for C style error codes (integers) to clearly identify the root cause and hopefully allow the error handler to overcome the error. You can wrap error codes from C libraries like SQLite in NSError instances very easily. NSError also has the benefit of being an object and offers a way to describe the error in more detail with its userInfo dictionary member. But best of all, NSError CANNOT be thrown so it encourages a more proactive approach to error handling, in contrast to other languages which simply throw the hot potato further and further up the call stack at which point it can only be reported to the user and not handled in any meaningful way (not if you believe in following OOP's biggest tenet of information hiding that is).
参考链接:参考
Regarding [NSException raise:format:]. For those coming from a Java background, you will recall that Java distinguishes between Exception and RuntimeException. Exception is a checked exception, and RuntimeException is unchecked. In particular, Java suggests using checked exceptions for "normal error conditions" and unchecked exceptions for "runtime errors caused by a programmer error." It seems that Objective-C exceptions should be used in the same places you would use an unchecked exception, and error code return values or NSError values are preferred in places where you would use a checked exception.
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