如何在PKPaymentRequest(ApplePay)中使用applicationData？

我想在Apple Pay上设置传递变量,我将其设置NSDictionary为JSON数据,如:

PKPaymentRequest *request = [[PKPaymentRequest alloc] init];
[request setApplicationData:[NSJSONSerialization dataWithJSONObject:@{@"name":@"USER_NAME"} options:NSJSONWritingPrettyPrinted error:nil]];

现在里面:

- (void)paymentAuthorizationViewController:(PKPaymentAuthorizationViewController *)controller didAuthorizePayment:(PKPayment *)payment completion:(void (^)(PKPaymentAuthorizationStatus status))completion;

我能够访问applicationData作为

NSError* jsonError;
NSDictionary* dataDict = [NSJSONSerialization JSONObjectWithData:payment.token.paymentData options:kNilOptions error:&jsonError];

dataDict [@"header"] [@"applicationData"]包含应用程序数据

但数据是编码的,我想@{@"name":@"USER_NAME"}从applicationData 获得.