Question

我正在尝试使用actor选择向actor发送消息。但它一直在死信。这是如何创建actor的（使用激活器模板）

class PingActor extends Actor with ActorLogging {
  import PingActor._

  var counter = 0
  val pongActor = context.actorOf(PongActor.props, "pongActor")
val tester = context.actorSelection("../pongActor") //getting the actor by name using the actorSelection 
  def receive = {
    case Initialize => 
        log.info("In PingActor - starting ping-pong")
      tester.tell(PingMessage("ping"),self)//going to dead letters
      tester ! PingMessage("ping")//also going to dead letters 
    case PongActor.PongMessage(text) =>
      log.info("In PingActor - received message: {}", text)
      counter += 1
      if (counter == 3) context.system.shutdown()
      else sender() ! PingMessage("ping")
  } 
}

object PingActor {
  val props = Props[PingActor]
  case object Initialize
  case class PingMessage(text: String)
}

这是派遣演员：

found = false;
double priceFound = 0;
for (int i = 0; i < 5; i++)
{
    if (order.Equals(toppings[i]))
    {
        found = true;
        priceFound = price[i]; // store the found price
    }
}

Console.WriteLine("The price of " + order + " is $" + priceFound);

为什么消息会传到死信
如何验证演员是否确实存在？

Answer 1

来自akka- docs

actorSelection只在传递消息时查找现有的actor，即在创建选择时不创建actor或验证actor的存在。

更好的选择是使用resolveOne

val timeout = 1.seconds
val tester1 = context.actorSelection("pongActor").resolveOne(timeout)

Answer 2

您的行CREATE TABLE hbase_table_1(key int, value string) STORED BY 'org.apache.hadoop.hive.hbase.HBaseStorageHandler' WITH SERDEPROPERTIES ("hbase.columns.mapping" = ":key,cf1:val") TBLPROPERTIES ("hbase.table.name" = "xyz"); **FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. org.apache.hadoop.hbase.HTableDescriptor.addFamily(Lorg/apache/hadoop/hbase/HColumnDescriptor;)V**是不必要的，因为上一行将val tester = context.actorSelection("../pongActor")设置为您需要的pongActor。只需使用actorRef和pongActor.tell代替pongActor !和tester.tell。

至于为什么tester !查找失败：当你在父actor中创建一个子actor时（这里actorSelection是父，Ping是孩子），路径到子项与父项的路径相同，并附加子项名称。因此，相对于Pong，Ping的路径只是“pongActor”，而不是“../ pongActor”。

如何通过名称验证akka actor是否存在

2 个答案: