objective-c - -[NSString stringByAppendingPathComponent :] or just -[NSString stringByAppendingFormat:] for NSStrings for NSURLs?

Question

当调用 +[NSURL URLWithString:] 时，我有两个构建 URL 的选项:

[[@"http://example.com" stringByAppendingPathComponent:@"foo"] stringByAppendingPathComponent:@"bar"]

或

[@"http://example.com" stringByAppendingFormat:@"/%@/%@",@"foo",@"bar"];

-[NSString stringByAppendingPathComponent:] 似乎是更正确的答案，但是除了像以下案例？

// http://example.com/foo/bar
[[@"http://example.com/" stringByAppendingPathComponent:@"/foo"] stringByAppendingPathComponent:@"bar"] 

// http://example.com//foo/bar  oops!
[@"http://example.com/" stringByAppendingFormat:@"/%@/%@",@"foo",@"bar"];

Answer 1

当你使用 URLS 时，你应该使用 NSURL 方法:

NSURL * url = [NSURL URLWithString: @"http://example.com"];
url = [[url URLByAppendingPathComponent:@"foo"] URLByAppendingPathComponent:@"bar"]

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或在 Swift 中

var url = NSURL.URLWithString("http://example.com")
url = url.URLByAppendingPathComponent("foo").URLByAppendingPathComponent(".bar")