什么"扔"; 靠自己呢？

Question

可能重复:
throw和throw之间的差异新异常()

有什么意义

catch (Exception)
{
    throw;
}

这是做什么的？

Answer 1

throw关键字本身只是重新引发上述catch语句捕获的异常.如果你想做一些基本的异常处理(可能是回滚事务的补偿操作),然后重新抛出调用方法的异常,这很方便.

与捕获变量中的异常并抛出该实例相比,此方法具有一个显着优势:它保留了原始调用堆栈.如果你捕获(Exception ex)然后抛出ex,你的调用堆栈将只从那个throw语句开始,你将丢失原始错误的方法/行.

Answer 2

有时你可能想做这样的事情:

try
{
    // do some stuff that could cause SomeCustomException to happen, as 
    // well as other exceptions
}
catch (SomeCustomException)
{
    // this is here so we don't double wrap the exception, since
    // we know the exception is already SomeCustomException
    throw;
}
catch (Exception e)
{
    // we got some other exception, but we want all exceptions
    // thrown from this method to be SomeCustomException, so we wrap
    // it
    throw new SomeCustomException("An error occurred saving the widget", e);
}