必须在 URL 路径中同等对待“@”和“%40”吗？
Must '@' and '%40' be treated equivalently in URL paths?
跟进 Can I use an at symbol (@) inside URLs?
根据 top voted answer，@ 不是 URL 路径中的保留字符（尽管它在主机中）。
但是，给定路径中的 @，URL 编码形式是否可以互换？换句话说，twitter.com/@user 是否严格等同于 twitter.com/%40user？
在实践中，它们似乎经常互换使用，但很好奇是否确实如此（例如 AbC@gmail.com 在技术上与 abc@gmail.com 不同，但几乎每个人都对它们一视同仁） .
更广泛地说，字符和 URL 编码版本何时需要相同对待，何时不同（例如 example.com/path%2Fasdf 与 example.com/path/asdf 不同）……
URI http://twitter.com/@user 和 http://twitter.com/%40user 不 等价。
URI 标准是 STD 66, which currently maps to RFC 3986 (which updates RFC 1738).
节 6.2.2.2. Percent-Encoding Normalization defines how to normalize percent-encoded URIs to compare them for equivalence (after uppercasing hexadecimal digits A-F, as defined by 6.2.2.1 Case Normalization).
它说：
[…] some URI producers percent-encode octets that do not require percent-encoding, resulting in URIs that are equivalent to their non-encoded counterparts. These URIs should be normalized by decoding any percent-encoded octet that corresponds to an unreserved character, as described in Section 2.3.
链接的第 2.3 节列出了未保留的字符，它们是：
- 阿尔法 (
a-z, A-Z)
- DIGIT (
0-9)
- . _ ~
本节还指出，即使没有发生规范化：
URIs that differ in the replacement of an unreserved character with its corresponding percent-encoded US-ASCII octet are equivalent: they identify the same resource.
@ 不是“未保留”集的一部分。它是 "reserved" set 的一部分，上面写着：
URIs that differ in the replacement of a reserved character with its corresponding percent-encoded octet are not equivalent.
跟进 Can I use an at symbol (@) inside URLs?
根据 top voted answer，@ 不是 URL 路径中的保留字符（尽管它在主机中）。
但是，给定路径中的 @，URL 编码形式是否可以互换？换句话说，twitter.com/@user 是否严格等同于 twitter.com/%40user？
在实践中，它们似乎经常互换使用，但很好奇是否确实如此（例如 AbC@gmail.com 在技术上与 abc@gmail.com 不同，但几乎每个人都对它们一视同仁） .
更广泛地说，字符和 URL 编码版本何时需要相同对待，何时不同（例如 example.com/path%2Fasdf 与 example.com/path/asdf 不同）……
URI http://twitter.com/@user 和 http://twitter.com/%40user 不 等价。
URI 标准是 STD 66, which currently maps to RFC 3986 (which updates RFC 1738).
节 6.2.2.2. Percent-Encoding Normalization defines how to normalize percent-encoded URIs to compare them for equivalence (after uppercasing hexadecimal digits A-F, as defined by 6.2.2.1 Case Normalization).
它说：
[…] some URI producers percent-encode octets that do not require percent-encoding, resulting in URIs that are equivalent to their non-encoded counterparts. These URIs should be normalized by decoding any percent-encoded octet that corresponds to an unreserved character, as described in Section 2.3.
链接的第 2.3 节列出了未保留的字符，它们是：
- 阿尔法 (
a-z,A-Z) - DIGIT (
0-9) -._~
本节还指出，即使没有发生规范化：
URIs that differ in the replacement of an unreserved character with its corresponding percent-encoded US-ASCII octet are equivalent: they identify the same resource.
@ 不是“未保留”集的一部分。它是 "reserved" set 的一部分，上面写着：
URIs that differ in the replacement of a reserved character with its corresponding percent-encoded octet are not equivalent.