Java中本例的方法实现
我刚刚看到这样的代码片段：
private static class DefaultErrorHandler<RT> implements ErrorHandler<RT> {
public RT handle(Object[] params, Throwable e) {
return Exceptions.throwUncheckedException(e);
}
}
现在我想知道静态方法 throwUncheckedException (Throwable e) 会准确返回什么以及如何在泛型方面实现它。
有人能给我举个例子吗？
I just saw a code snippet like this:
private static class DefaultErrorHandler<RT> implements ErrorHandler<RT> {
public RT handle(Object[] params, Throwable e) {
return Exceptions.throwUncheckedException(e);
}
}
Now I am wondering what the static method throwUncheckedException (Throwable e) would return exactly and how it might be implemented regarding the generics.
Can anybody give me an example ?
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您可以像这样定义该方法：
这本质上意味着“对于任何类型 T，返回它”。然后，您依靠编译器猜测 T = RT 的能力。
我认为从 throwUncheckedException 方法返回值的想法如下：您想要调用一个总是抛出运行时异常的方法，并且从非 void 方法中调用它。 Java 编译器抱怨调用者在每个执行分支的末尾都需要一个 return 语句。这个技巧可以让你省去“虚拟返回”的麻烦。
You would define the method like this:
which essentially means "for any type T, return it". Then you rely on the compiler's ability to guess that T = RT.
I think the idea of returning a value from the
throwUncheckedExceptionmethod is as follows: you want to call a method that always throws a run-time exception, and you call it from a non-void method. Java compiler complains that the caller needs a return statement at the end of every execution branch. This trick saves you the need for a "dummy return".我不得不猜测它包含：
抛出新的RuntimeException(e);但实际上，我猜测返回值只是为了显示。该方法称为“抛出”。
如果它返回某些内容，它会返回“RT”类型的内容，无论是什么。
I would have to guess that it consists of :
throw new RuntimeException(e);but really, I'm guessing that the return value is just for show. The method is called 'throw'.
If it returns something, it returns something of type 'RT', whatever that is.
让方法 throwUncheckedException() 返回某些内容可以避免在需要返回值的调用方法中出现额外的行。
如果异常是直接从handle方法抛出的，如下所示：
将不需要return语句（实际上它甚至是非法的），因为编译器将能够知道抛出之后的任何语句都是不可访问的。
但由于 throw 是在另一个方法中完成的，并且由于 handler 方法需要返回值，因此必须添加返回语句。
让 throwUncheckedException() 返回一些内容允许调用位于 return 语句中。
throwUncheckedException() 必须接近于：
恕我直言，这提出了你的问题这一事实表明它太令人费解了，不值得。也许实现相同目标的更好方法是这样的：
Having the method throwUncheckedException() returning something avoids an extra line in a calling method that needs a return value.
Had the exception been thrown directly from the handle method as follows:
The return statement would not have been needed (it would even have been illegal actually) because the compiler would be able to know that any statement following the throw would be unreachable.
But since the throw is done in another method, and since a return value is required for the handle method, a return statememt must be added.
Having the throwUncheckedException() return something allows the call to be in the return statement.
The throwUncheckedException() must be something close to:
IMHO, the fact that this raised your question shows that it is too puzzling to be worthy. Perhaps a better way to achieve the same goal would be something like this: