无法访问@Field全局变量

Question

我的Groovy脚本中有这些全局变量

@Field ZonedDateTime currentDateTime = ZonedDateTime.now(ZoneId.of("UTC"))

@Field DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss.SSSZ")

但是我似乎无法在脚本的类内部访问它：（

class SmsMessageDeliveryPartResult {
    String dateSent
    String dateDeliveryReceiptReceived

    DeliveryResult() {
        this.dateSent = currentDateTime.format(formatter)
        this.dateDeliveryReceiptReceived = currentDateTime.format(formatter)
    }
}

我收到此错误：

Caught: groovy.lang.MissingPropertyException: No such property: currentDateTime for class: