在 class Actors.FileObserverActor 上找不到参数的匹配构造函数

Question

我正在尝试在 play frmework 中使用 akka actors 来实现 websocket。

HomeController.scala

  def socket = WebSocket.accept[String, String] { request =>
    ActorFlow.actorRef(out => FileObserverActor.props(out))
  }

Actors/FileUploaderActor.scala

class FileUploaderActor extends Actor{
  override def receive: Receive = {

    case UploadFile(billerId, filename, subCategory, count, dueDate) =>

      val fileOberverActor = ActorSystem().actorOf(Props[FileObserverActor])
      val billerData = BillerFileUploadMetaData(billerId,filename,count,"ACTIVE",
        new java.sql.Timestamp(new java.util.Date().getTime),subCategory,dueDate)
      val sparkSession = SparkContextHelper.sparkSession;
      import sparkSession.implicits._
      val rdd = sparkSession.sparkContext.parallelize(Seq(billerData))
      val df = rdd.toDF()
      df.write.format("org.apache.spark.sql.cassandra").options(Map("keyspace" -> "billerplatform_schema", "table" -> "biller_file_uploads")).mode(SaveMode.Append).save
      fileOberverActor ! FileUploaded(filename, count)
  }
}

Actors/FileObserverActor.scala

class FileObserverActor(out: ActorRef) extends Actor{
  def receive = {
    case FileUploaded(fileName, totalRecords) =>
      out ! ("Got the file " + fileName)
  }

}

object FileObserverActor{
  def props(out: ActorRef)  = Props(new FileObserverActor(out))
}

获取跟踪：

java.lang.IllegalArgumentException: no matching constructor found on class Actors.FileObserverActor for arguments []
    at akka.util.Reflect$.error(Reflect.scala:81)
    at akka.util.Reflect$.findConstructor(Reflect.scala:105)
    at akka.actor.NoArgsReflectConstructor.<init>(IndirectActorProducer.scala:103)
    at akka.actor.IndirectActorProducer$.apply(IndirectActorProducer.scala:60)
    at akka.actor.Props.producer(Props.scala:131)
    at akka.actor.Props.<init>(Props.scala:144)
    at akka.actor.Props$.apply(Props.scala:86)
    at Actors.FileUploaderActor$$anonfun$receive.applyOrElse(FileUploaderActor.scala:15)
    at akka.actor.Actor$class.aroundReceive(Actor.scala:497)
    at Actors.FileUploaderActor.aroundReceive(FileUploaderActor.scala:10)

这是在 FileUploaderActor 中创建 actor 实例的问题吗？你能帮我调试这个问题吗？

编辑：我为 "FileObserverActor" 创建了一个伴随对象，因为它需要通过 websocket 在控制器和 FileObserverActor 之间建立连接，

def socket = WebSocket.accept[String, String] { request =>
    ActorFlow.actorRef(out => FileObserverActor.props(out))
  }

现在我还想从 "FileUploadActor" 向 "FileObserverActor" 发送消息，但是我无法从 "FileUploadActor" 创建实例，因为 "FileObserverActor" 是用 [=38 参数化的=] 用于 websocket 连接。现在如何从 "FileUploadActor" 向 "FileObserverActor" 发送消息？

Answer 1

正如错误消息所指出的那样，它期待 FileObserverActor 的无参数构造函数，但未找到。鉴于您在创建 FileObserverActor 时需要 out: ActorRef，请考虑在创建它时传递引用。

违规行在 Actors/FileUploaderActor.scala

val fileOberverActor = ActorSystem().actorOf(Props[FileObserverActor])

您可能想将其更改为

val fileOberverActor = ActorSystem().actorOf(FileObserverActor.props(outActorRef))

有关更多信息，请查看 Akka 中有关 Props 的官方文档。

在 class Actors.FileObserverActor 上找不到参数的匹配构造函数

No matching constructor found on class Actors.FileObserverActor for arguments

scala

websocket

actor

akka

playframework