+ (NSString *)urlEncode:(NSString *)url {

? ? NSString *charactersToEscape =@"[]";

? ? NSCharacterSet *allowedCharacters = [[NSCharacterSet characterSetWithCharactersInString:charactersToEscape] invertedSet];

? ? NSString * urlStr = [url stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacters];

? ? return urlStr;

}

+ (NSString *)urlDecode:(NSString *)url {

? ? NSString* decodedString = [url stringByRemovingPercentEncoding];

? ? return decodedString;

}