问题
I am confused by Apple's documentation about the NSURL class.
In NSURL, they say the following:
- NSURL understands URLs in style of RFC 1808, 1738 und 2732
- NSURL understands URIs in style of RFC 2396
Also they say that the RFC 2396 URI are paths.
Now what's the difference here? Isn't a path also an URL? I mean, it's an location or not?
回答1:
Both URLs and URIs identify resources (which are anything). However, a URL is the term used for an identifier that specifies how to locate the resource.
Let's consider other kinds of identifiers to help make this clear. An ISBN code identifies a book but does not specify how to find it. A Dewey Decimal or Library of Congress number also identifies a book and is also used to organize books in a library -- given the number you can find the book on a shelf in the library.
Getting back to URIs and URLs, a URI that refers to the location or path of a file is by definition a URL.
NSURL can also be used to parse and manipulate URIs that do not locate resources but merely identify them.
来源：https://stackoverflow.com/questions/2109298/is-it-right-to-say-that-paths-are-represented-as-uri-while-web-addresses-are-rep