2

我有一个如下所示的调度程序。它意味着每 30 分钟向 Actor 系统中的另一个 Actor 发送一条消息。当我在 eclipse IDE for scala 中运行此代码时，它运行良好。但是，当我在 MicroKernel 中抛出此代码（使用可引导代码以便 Microkernel 可以调用它）时，我得到一个异常说

java.lang.NoSuchMethodError:akka.actor.ActorSystem.dispatcher()Lscala/concurrent/ExecutionContext; 完整的堆栈跟踪如下所示。我怀疑问题可能与在此上下文中无效的“import system.dispatcher”行有关。或者调度程序试图过早地触发消息。

请帮忙...

调度程序.scala：

import akka.actor.Actor
import akka.actor.Props
import scala.concurrent.duration._
import akka.actor._
import java.sql.Timestamp;
import java.util.Date;

class Scheduler extends Actor with ActorLogging {
    import transactions._

    val system = ActorSystem("Daemon")
    import system.dispatcher
    log.info("Scheduler initializing.")
    system.scheduler.schedule( 30 milliseconds, (1000*60*30 ) milliseconds){ 
                self! updateUows(new Timestamp(new java.util.Date().getTime()))}

    def receive = {

    case updateUows(time) => { 
        log.info("updateuow to be sent.")
        context.parent!updateUows(time) 
    }
    }

}

完整的堆栈跟踪：

    [DEBUG] [07/26/2013 15:38:23.324] [Daemon-akka.actor.default-dispatcher-4] [EventStream(akka://Daemon)] Default Loggers started
Uncaught error from thread [Daemon-akka.actor.default-dispatcher-4] shutting down JVM since 'akka.jvm-exit-on-fatal-error' is enabled for ActorSystem[Daemon[ERROR] [07/26/2013
15:38:23.960] [Daemon-akka.actor.default-dispatcher-4] [ActorSystem(Daemon)] Uncaught error from thread [Daemon-akka.actor.default-dispatcher-4] shutting down JVM since 'akka
.jvm-exit-on-fatal-error' is enabled
java.lang.NoSuchMethodError: akka.actor.ActorSystem.dispatcher()Lscala/concurrent/ExecutionContext;
        at org.exactearth.PVDaemon.Scheduler$$anonfun$receive$1.applyOrElse(Scheduler.scala:25)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:425)
        at akka.actor.ActorCell.invoke(ActorCell.scala:386)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:230)
        at akka.dispatch.Mailbox.run(Mailbox.scala:212)
        at akka.dispatch.ForkJoinExecutorConfigurator$MailboxExecutionTask.exec(AbstractDispatcher.scala:506)
        at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
        at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
        at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
        at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
]

java.lang.NoSuchMethodError: akka.actor.ActorSystem.dispatcher()Lscala/concurrent/ExecutionContext;
        at org.exactearth.PVDaemon.Scheduler$$anonfun$receive$1.applyOrElse(Scheduler.scala:25)
        at akka.actor.ActorCell.receiveMessage(ActorCell.scala:425)
        at akka.actor.ActorCell.invoke(ActorCell.scala:386)
        at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:230)
        at akka.dispatch.Mailbox.run(Mailbox.scala:212)
        at akka.dispatch.ForkJoinExecutorConfigurator$MailboxExecutionTask.exec(AbstractDispatcher.scala:506)
        at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
        at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
        at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
        at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

Shutting down Akka...
Shutting down .............(my program)
4

3 回答 3

1

它应该使用 ActorSystem 创建 Actor，如下面的代码所示：

case object StartSched

class Test extends Actor with ActorLogging {
  def receive = {
    case StartSched =>
      context.system.scheduler.schedule( 30 milliseconds, (1000*60*30) milliseconds){
        self ! updateUows(new Timestamp(new java.util.Date().getTime()))
      }
  }
}

object Main {
  def main(args: Array[String]) {
    val sys = ActorSystem("Test")
    sys.actorOf(Props[Test])
  }
}

要在 MicroKernel 中启动它，您应该扩展Bootabletrait 并重载两个方法：startup和shutdown. 文档

在 Actor 内部创建 ActorSystem是一个非常糟糕的决定。

于 2013-07-26T20:42:02.260 回答
1

我的代码遇到的问题是它试图创建 ActorSystem。

并且 import system.dispatcher 是代码失败的原因。

相反， import scala.concurrent.ExecutionContext.Implicits.global 行给出了要使用的默认 executionContext。

感谢 Alex 引导我朝着正确的方向前进。

case object StartSched

class Scheduler extends Actor with ActorLogging {
    import transactions._
    log.info("Scheduler initializing.")
    self!StartSched
    def receive = {
    case StartSched =>{
    import scala.concurrent.ExecutionContext.Implicits.global
    context.system.scheduler.schedule( 30 milliseconds, (1000*60*30) milliseconds){
        self ! updateUows(new Timestamp(new java.util.Date().getTime()))
      }
    }
    case updateUows(time) => { 
        log.info("updateuow to be sent.")
        context.parent!updateUows(time) 
    }
    case _=>{log.info("Don't know why we reached here.")}

}
}
于 2013-07-27T14:52:43.027 回答
1

罗兰在评论中的回答是正确的。Scala 中的 java.lang.NoSuchMethodError 通常意味着您使用了二进制不兼容的库。

您可以在 IDE 项目和微内核应用程序中使用不同的主要 Scala 版本，或者使用不同的主要 Akka 版本。

于 2013-07-29T08:49:39.037 回答