NSURLComponents的使用

我们开发中经常会用到NSURL,有时候我们需要对一个url进行分析整理，当然是可以按照RFC 1808的定义去自己分析，但是苹果已经给我们提供了解析url的方法，就是iOS 7时添加的NSURLComponents。

初始化方法如下：

// 
- (instancetype)init;
// 
- (nullable instancetype)initWithURL:(NSURL *)url resolvingAgainstBaseURL:(BOOL)resolve;
// 
+ (nullable instancetype)componentsWithURL:(NSURL *)url resolvingAgainstBaseURL:(BOOL)resolve;
// 
- (nullable instancetype)initWithString:(NSString *)URLString;
// 
+ (nullable instancetype)componentsWithString:(NSString *)URLString;

常用的属性如下：

@property (nullable, readonly, copy) NSURL *URL;

@property (nullable, readonly, copy) NSString *string NS_AVAILABLE(10_10, 8_0);



@property (nullable, copy) NSString *scheme; // Attempting to set the scheme with an invalid scheme string will cause an exception.
@property (nullable, copy) NSString *user;
@property (nullable, copy) NSString *password;
@property (nullable, copy) NSString *host;
@property (nullable, copy) NSNumber *port; // Attempting to set a negative port number will cause an exception.
@property (nullable, copy) NSString *path;
@property (nullable, copy) NSString *query;
@property (nullable, copy) NSString *fragment;



@property (nullable, copy) NSString *percentEncodedUser;
@property (nullable, copy) NSString *percentEncodedPassword;
@property (nullable, copy) NSString *percentEncodedHost;
@property (nullable, copy) NSString *percentEncodedPath;
@property (nullable, copy) NSString *percentEncodedQuery;
@property (nullable, copy) NSString *percentEncodedFragment;


@property (nullable, copy) NSArray<NSURLQueryItem *> *queryItems NS_AVAILABLE(10_10, 8_0);

比如http://help.baidu.com:80/question?prod_id=1#!/feedback，scheme就是http, host是help.baidu.com, port就是80, path就是/question, query就是prod_id=1, fragment = !/feedback。