关于urlencode

//URLEncode
+(NSString*)encodeString:(NSString*)unencodedString{
    
    // CharactersToBeEscaped = @":/?&=;+!@#$()~‘,*";
    // CharactersToLeaveUnescaped = @"[].";
    
    NSString *encodedString = (NSString *)
    CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                              (CFStringRef)unencodedString,
                                                              NULL,
                                                              (CFStringRef)@"+",
                                                              kCFStringEncodingUTF8));
    
    return encodedString;
}