![](/img/trans.png)
[英]Scala <console>:24: error: could not find implicit value for evidence parameter of type breeze.storage.DefaultArrayValue[Any]
[英]Scala compile error - could not find implicit value for evidence parameter of type
我在以下案例類中使用Spray json序列化
case class ActivationMessage(override val transid: TransactionId,
action: FullyQualifiedEntityName,
revision: DocRevision,
user: Identity,
activationId: ActivationId,
activationNamespace: EntityPath,
content: Option[JsObject],
cause: Option[ActivationId] = None,
traceMetadata: Option[SpanMetadata] = None
) extends Message {
def meta = JsObject("meta" -> {
cause map {
c => JsObject(c.toJsObject.fields ++ activationId.toJsObject.fields)
} getOrElse {
activationId.toJsObject
}
})
override def serialize = ActivationMessage.serdes.write(this).compactPrint
override def toString = {
val value = (content getOrElse JsObject()).compactPrint
s"$action?message=$value"
}
def causedBySequence: Boolean = cause.isDefined
}
object ActivationMessage extends DefaultJsonProtocol {
def parse(msg: String) = Try(serdes.read(msg.parseJson))
private implicit val fqnSerdes = FullyQualifiedEntityName.serdes
implicit val serdes = jsonFormat9(ActivationMessage.apply)
}
我收到編譯錯誤提示-找不到類型為ActivationMessage.JF[Option[com.github.levkhomich.akka.tracing.SpanMetadata]]
證據參數的隱含值
如果我從構造函數中刪除最后一個參數,並使用jsonFormat8,那么一切都會編譯正常。 如何在沒有任何編譯問題的情況下添加此額外參數?
編譯器找不到JsonFormat
的隱式SpanMetadata
。 嘗試:
...
object ActivationMessage extends DefaultJsonProtocol {
...
private implicit val spanMetaSerdes = jsonFormat4(SpanMetadata.apply)
implicit val serdes = jsonFormat9(ActivationMessage.apply)
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.