我正在尝试使用akka actors建立一个简单的TCP服务器,它应该允许多个客户端同时连接。我将我的问题简化为以下简单程序:
package actorfail
import akka.actor._, akka.io._, akka.util._
import scala.collection.mutable._
import java.net._
case class Foo()
class ConnHandler(conn: ActorRef) extends Actor {
def receive = {
case Foo() => conn ! Tcp.Write(ByteString("foo\n"))
}
}
class Server(conns: ArrayBuffer[ActorRef]) extends Actor {
import context.system
println("Listing on 127.0.0.1:9191")
IO(Tcp) ! Tcp.Bind(self, new InetSocketAddress("127.0.0.1", 9191))
def receive = {
case Tcp.Connected(remote, local) =>
val handler = context.actorOf(Props(new ConnHandler(sender)))
sender ! Tcp.Register(handler)
conns.append(handler)
}
}
object Main {
def main(args: Array[String]) {
implicit val system = ActorSystem("Test")
val conns = new ArrayBuffer[ActorRef]()
val server = system.actorOf(Props(new Server(conns)))
while (true) {
println(s"Sending some foos")
for (c <- conns) c ! Foo()
Thread.sleep(1000)
}
}
}
它绑定到localhost:9191并接受多个连接,将连接处理程序添加到全局数组中,并周期性地向每个连接发送字符串"foo"。现在当我尝试同时与多个客户端连接时,只有第一个客户端会收到"foo"。当我打开第二个连接时,它不会得到任何foo,而是会得到以下类型的日志消息:
Sending some foos
[INFO] [03/27/2015 21:24:07.331] [Test-akka.actor.default-dispatcher-6] [akka://Test/deadLetters] Message [akka.io.Tcp$Write] from Actor[akka://Test/user/$a/$b#-308726290] to Actor[akka://Test/deadLetters] was not delivered. [7] dead letters encountered. This logging can be turned off or adjusted with configuration settings 'akka.log-dead-letters' and 'akka.log-dead-letters-during-shutdown'.
我理解这意味着我们试图发送Tcp.Write
命令到的目标 actor 不再接受消息。但这是为什么呢?你能帮我理解其中潜在的问题吗?我该如何让它起作用?