Foundation - NSURL路径

URL

URL(统一资源定位符) ，通过这个url来找对对应的资源。

NSURL

主要是因为网站地址的字符串都比较复杂，包括很多请求参数，这样在请求过程中需要解析出来每个部门，所以苹果封装一个NSURL，操作很方便。

一个 NSURL 对象代表了一个表示远程服务器资源或者本地文件的 URL。所以在 iOS 的网络请求和操作文件系统的 API 中，很多都需要 NSURL 类型的参数。

url字符串编码处理：http://www.jianshu.com/p/917cec978530

URL结构分析

hierarchical part
        ┌───────────────────┴─────────────────────┐
                    authority               path
        ┌───────────────┴───────────────┐┌───┴────┐
  abc://username:password@example.com:123/path/data?key=value&key2=value2#fragid1
  └┬┘   └───────┬───────┘ └────┬────┘ └┬┘           └─────────┬─────────┘ └──┬──┘
scheme  user information     host     port                  query         fragment

  urn:example:mammal:monotreme:echidna
  └┬┘ └────────────┬───────────────┘
scheme              path

作者：二巷小鞭
链接：http://www.jianshu.com/p/38f5f53dfbad

NSURL属性

@property (nullable, readonly, copy) NSString *absoluteString;
@property (readonly, copy) NSString *relativeString; 
@property (nullable, readonly, copy) NSURL *baseURL;
@property (nullable, readonly, copy) NSURL *absoluteURL;
@property (nullable, readonly, copy) NSString *scheme;
@property (nullable, readonly, copy) NSString *resourceSpecifier;

@property (nullable, readonly, copy) NSString *host;
@property (nullable, readonly, copy) NSNumber *port;
@property (nullable, readonly, copy) NSString *user;
@property (nullable, readonly, copy) NSString *password;
@property (nullable, readonly, copy) NSString *path;
@property (nullable, readonly, copy) NSString *fragment;
@property (nullable, readonly, copy) NSString *parameterString;
@property (nullable, readonly, copy) NSString *query;
@property (nullable, readonly, copy) NSString *relativePath;

代码例子：

NSURL *url = [NSURL URLWithString:@"http://www.baidu.com/s?tn=baiduhome_pg&bs=NSRUL&f=8&rsv_bp=1&rsv_spt=1&wd=NSurl&inputT=2709"];  
      
    NSLog(@"Scheme: %@", [url scheme]);  
    NSLog(@"Host: %@", [url host]);  
    NSLog(@"Port: %@", [url port]);  
    NSLog(@"Path: %@", [url path]);  
    NSLog(@"Relative path: %@", [url relativePath]);  
    NSLog(@"Path components as array: %@", [url pathComponents]);  
    NSLog(@"Parameter string: %@", [url parameterString]);  
    NSLog(@"Query: %@", [url query]);  
    NSLog(@"Fragment: %@", [url fragment]);  
    NSLog(@"User: %@", [url user]);  
    NSLog(@"Password: %@", [url password]);  

//======================输出如下=====================：
2012-08-29 15:52:23.781 NSurl[3560:f803] Scheme: http  
2012-08-29 15:52:32.793 NSurl[3560:f803] Host: www.baidu.com  
2012-08-29 15:52:39.102 NSurl[3560:f803] Port: (null)  
2012-08-29 15:52:42.590 NSurl[3560:f803] Path: /s  
2012-08-29 15:52:52.516 NSurl[3560:f803] Relative path: /s  
2012-08-29 15:53:05.576 NSurl[3560:f803] Path components as array: (  
    "/",  
    s  
)  
2012-08-29 15:53:32.861 NSurl[3560:f803] Parameter string: (null)  
2012-08-29 15:53:37.528 NSurl[3560:f803] Query: tn=baiduhome_pg&bs=NSRUL&f=8&rsv_bp=1&rsv_spt=1&wd=NSurl&inputT=2709  
2012-08-29 15:53:52.942 NSurl[3560:f803] Fragment: (null)  
2012-08-29 15:53:54.539 NSurl[3560:f803] User: (null)  
2012-08-29 15:53:57.808 NSurl[3560:f803] Password: (null)  

常用方法

• URLWithString:

• initWithString:

• fileURLWithPath:

• initFileURLWithPath:

NSURLComponents

NSURLComponents 是一个用于解析和构建 URL 的类，
通过 NSURLComponents 可以单独修改 URL 的某一部分，获取某一部分编码后的值。

创建一个 NSURLComponents 实例

    NSURLComponents *c = [NSURLComponents componentsWithString:@"http://baidu.com:80?a=a&b=b#cc"];
    NSLog(@"URL：%@",c.URL);
    NSLog(@"scheme：%@",c.scheme);
    NSLog(@"user：%@",c.user);
    NSLog(@"password：%@",c.password);
    NSLog(@"host：%@",c.host);
    NSLog(@"port：%@",c.port);
    NSLog(@"path：%@",c.path);
    NSLog(@"query：%@",c.query);
    NSLog(@"fragment：%@",c.fragment);//fragment：cc
    c.fragment = @"ddddd";
    NSLog(@"fragment：%@",c.fragment); //fragment：ddddd

    NSLog(@"percentEncodedUser：%@",c.percentEncodedUser);
    NSLog(@"percentEncodedPassword：%@",c.percentEncodedPassword);
    NSLog(@"percentEncodedHost：%@",c.percentEncodedHost);
    NSLog(@"percentEncodedPath：%@",c.percentEncodedPath);
    NSLog(@"percentEncodedQuery：%@",c.percentEncodedQuery);
    NSLog(@"percentEncodedFragment：%@",c.percentEncodedFragment);

参考：
http://www.jianshu.com/p/38f5f53dfbad