在Objective-C中获取NSURL的一部分 [英] Get parts of a NSURL in objective-c

问题描述

我有一个NSString，值是

I have an NSString with the value of

http://digg.com/news/business/24hr

如何获得3级之前的一切?

How can I get everything before the 3rd level?

http://digg.com/news/

推荐答案

请注意，这并不完全是第三级.像这样分割URL:

This isn't exactly the third level, mind you. An URL is split like that way:

• 协议或方案(此处为http)
• ://分隔符
• 用户名和密码(这里没有，但可以是username:password@hostname)
• 主机名(此处为digg.com)
• 端口(例如，域名后的:80)
• 路径(此处为/news/business/24hr)
• 参数字符串(分号后的任何内容)
• 查询字符串(如果您具有诸如?foo=bar&baz=frob之类的GET参数，则为该字符串)
• 片段(如果您在链接中有锚点，例如#foobar).

• the protocol or scheme (here, http)
• the :// delimiter
• the username and the password (here there isn't any, but it could be username:password@hostname)
• the host name (here, digg.com)
• the port (that would be :80 after the domain name for instance)
• the path (here, /news/business/24hr)
• the parameter string (anything that follows a semicolon)
• the query string (that would be if you had GET parameters like ?foo=bar&baz=frob)
• the fragment (that would be if you had an anchor in the link, like #foobar).

功能齐全"的网址如下所示:

A "fully-featured" URL would look like this:

http://foobar:[e-mail]:8080/some/path/file.html;params-here?foo=bar#baz

NSURL具有广泛的访问器.您可以在

NSURL has a wide range of accessors. You may check them in the documentation for the NSURL class, section Accessing the Parts of the URL. For quick reference:

• -[NSURL scheme] = http
• -[NSURL resourceSpecifier] =(从//到URL末尾的所有内容)
• -[NSURL user] = foobar
• -[NSURL password] =尼古丁
• -[NSURL host] = example.com
• -[NSURL port] = 8080
• -[NSURL path] =/some/path/file.html
• -[NSURL pathComponents] = @ ["/"，"some"，"path"，"file.html"](请注意，开头的/是其中的一部分)
• -[NSURL lastPathComponent] = file.html
• -[NSURL pathExtension] = html
• -[NSURL parameterString] = params-here
• -[NSURL query] = foo = bar
• -[NSURL fragment] = baz

• -[NSURL scheme] = http
• -[NSURL resourceSpecifier] = (everything from // to the end of the URL)
• -[NSURL user] = foobar
• -[NSURL password] = nicate
• -[NSURL host] = example.com
• -[NSURL port] = 8080
• -[NSURL path] = /some/path/file.html
• -[NSURL pathComponents] = @["/", "some", "path", "file.html"] (note that the initial / is part of it)
• -[NSURL lastPathComponent] = file.html
• -[NSURL pathExtension] = html
• -[NSURL parameterString] = params-here
• -[NSURL query] = foo=bar
• -[NSURL fragment] = baz

不过，您想要的是这样的东西:

What you'll want, though, is something like that:

NSURL* url = [NSURL URLWithString:@"http://digg.com/news/business/24hr"];
NSString* reducedUrl = [NSString stringWithFormat:
    @"%@://%@/%@",
    url.scheme,
    url.host,
    url.pathComponents[1]];

对于您的示例URL，您似乎想要的是协议，主机和第一个路径组件. (-[NSString pathComponents]返回的数组中索引0处的元素只是"/"，因此您需要索引1处的元素.其他斜杠将被丢弃.)

For your example URL, what you seem to want is the protocol, the host and the first path component. (The element at index 0 in the array returned by -[NSString pathComponents] is simply "/", so you'll want the element at index 1. The other slashes are discarded.)

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