iOS url出现特殊字符处理 -- stringByAddingPercentEncodingWithAllowedCharacters

来源：cnblogs　　作者：久依　　时间：2018/12/14 9:25:45　　对本文有异议

stringByAddingPercentEscapesUsingEncoding(只对 `#%^{}[]|\"<> 加空格共14个字符编码，不包括”&?”等符号), ios9将淘汰，建议用 stringByAddingPercentEncodingWithAllowedCharacters 方法

stringByAddingPercentEncodingWithAllowedCharacters 需要传一个 NSCharacterSet 对象（关于 NSCharacterSet 这篇文章说的很好）

如[NSCharacterSet URLQueryAllowedCharacterSet]

URLFragmentAllowedCharacterSet  "#%<>[\]^`{|}
URLHostAllowedCharacterSet      "#%/<>?@\^`{|}
URLPasswordAllowedCharacterSet  "#%/:<>?@[\]^`{|}
URLPathAllowedCharacterSet      "#%;<>?[\]^`{|}
URLQueryAllowedCharacterSet    "#%<>[\]^`{|}
URLUserAllowedCharacterSet      "#%/:<>?@[\]^`

（2）网络访问请求：中文空格字符解码

stringByRemovingPercentEncoding ---- xcode7可能会提示要将stringByAddingPercentEscapesUsingEncoding替换成此方法，要根据是否是解码来区分

代替 stringByAddingPercentEscapesUsingEncoding

let customAllowedSet =  NSCharacterSet(charactersInString:"`#%^{}\"[]|\\<> ").invertedSet
NSString *urlStr = [urlStr stringByAddingPercentEncodingWithAllowedCharacters:[[NSCharacterSet characterSetWithCharactersInString:@"?!@#$^&%*+,:;='\"`<>()[]{}/\\| "] invertedSet]];