ios urlencode

+ (NSString *)URLEncodedString:(NSString *)string {
    NSString *encodedString = (NSString *)
    CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                              (CFStringRef)string,
                                                              NULL,
                                                              (CFStringRef)@"!*'();:@&=+$,/?%#[]",
                                                              kCFStringEncodingUTF8));
    
    return encodedString;
}