iOS url endcode

ios-url-encode.mm

/**
 * 1. [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding] 会导致=等符号转换
 * 成urf8的编码\u003d导致url无法正常解析
 * 2. [NSURL URLWithString:url] 又会导致中文等字符无法encode
 */
- (NSString*)encodeUrl:(NSString*)string
{
    NSString* encodedString = (NSString*)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                                                                   (CFStringRef)self,
                                                                                                   (CFStringRef) @"!$&'()*+,-./:;=?@_~%#[]",
                                                                                                   NULL,
                                                                                                   kCFStringEncodingUTF8));
    return encodedString;
}