? ?上篇我們討論了Akka-Remoting。我們說Akka-Remoting是一種點對點的通訊方式，能使兩個不同JVM上Akka-ActorSystem上的兩個Actor之間可以相互溝通。Akka-Remoting還沒有實現完全的Actor位置透明（location transparency），因為一個Actor還必須在獲得對方Actor確切地址信息后才能啟動與之溝通過程。Akka-Remoting支持“遠程查找”和“遠程構建”兩種溝通方式。由于篇幅所限，我們只介紹了“遠程查找”。在這一篇里我們將會討論“遠程構建”方式。

同樣，我們先通過項目結構來分析：

lazy val local = (project in file(".")).settings(commonSettings).settings(name := "remoteCreateDemo").aggregate(calculator,remote).dependsOn(calculator)lazy val calculator = (project in file("calculator")).settings(commonSettings).settings(name := "calculator")lazy val remote = (project in file("remote")).settings(commonSettings).settings(name := "remoteSystem").aggregate(calculator).dependsOn(calculator)

遠程構建的過程大致是這樣的：由local通知remote啟動構建Actor；remote從本地庫中查找Actor的類定義（class）并把它載入內存。由于驅動、使用遠程Actor是在local進行的，所以local,remote項目還必須共享Calculator，包括Calculator的功能消息。這項要求我們在.sbt中用aggregate(calculator)來協同編譯。

我們把Calculator的監管supervisor也包括在這個源碼文件里。現在這個calculator是個包括監管、功能、消息的完整項目了。Calculator源代碼如下：

package remoteCreation.calculatorimport akka.actor._ import scala.concurrent.duration._object Calcultor {sealed trait MathOpscase class Num(dnum: Double) extends MathOpscase class Add(dnum: Double) extends MathOpscase class Sub(dnum: Double) extends MathOpscase class Mul(dnum: Double) extends MathOpscase class Div(dnum: Double) extends MathOpssealed trait CalcOpscase object Clear extends CalcOpscase object GetResult extends CalcOpsdef props = Props(new Calcultor)def supervisorProps = Props(new SupervisorActor) }class Calcultor extends Actor with ActorLogging {import Calcultor._var result: Double = 0.0 //internal stateoverride def receive: Receive = {case Num(d) => result = dcase Add(d) => result += dcase Sub(d) => result -= dcase Mul(d) => result *= dcase Div(d) =>val _ = result.toInt / d.toInt //yield ArithmeticExceptionresult /= dcase Clear => result = 0.0case GetResult =>sender() ! s"Result of calculation is: $result"}override def preRestart(reason: Throwable, message: Option[Any]): Unit = {log.info(s"Restarting calculator: ${reason.getMessage}")super.preRestart(reason, message)} }class SupervisorActor extends Actor {def decider: PartialFunction[Throwable,SupervisorStrategy.Directive] = {case _: ArithmeticException => SupervisorStrategy.Resume}override def supervisorStrategy: SupervisorStrategy =OneForOneStrategy(maxNrOfRetries = 5, withinTimeRange = 5 seconds){decider.orElse(SupervisorStrategy.defaultDecider)}val calcActor = context.actorOf(Calcultor.props,"calculator")override def receive: Receive = {case msg@ _ => calcActor.forward(msg)}}

與上一個例子的”遠程查找式“相同，remote需要為Remoting公開一個端口。我們可以照搬.conf配置文件內容：remote/src/main/resources/application.conf

akka {actor {provider = remote}remote {enabled-transports = ["akka.remote.netty.tcp"]netty.tcp {hostname = "127.0.0.1"port = 2552}log-sent-messages = onlog-received-messages = on} }

由于遠程構建和使用是在local上進行的，在remote上我們只需要啟動ActorSystem就行了：

import com.typesafe.config.ConfigFactory import akka.actor._object CalculatorRunner extends App {val remoteSystem = ActorSystem("remoteSystem",ConfigFactory.load("application"))println("Remote system started.")scala.io.StdIn.readLine()remoteSystem.terminate()}

Calculator的構建是在localSystem上啟動的，我們需要在配置文件中描述遠程構建標的（還是未能實現位置透明）：local/src/main/resources/application.conf?

akka {actor {provider = remote,deployment {"/calculator" {remote = "akka.tcp://remoteSystem@127.0.0.1:2552"}}}remote {netty.tcp {hostname = "127.0.0.1",port=2554}} }

注意：上面這個/calculator設置實際上指的是SupervisorActor。

現在我們可以在local上開始構建calculator，然后使用它來運算了：

import akka.actor._ import remoteCreation.calculator.Calcultor._ import scala.concurrent.duration._ import akka.pattern._object RemotingCreate extends App {val localSystem = ActorSystem("localSystem")val calcActor = localSystem.actorOf(props,name = "calculator") //created SupervisorActorimport localSystem.dispatchercalcActor ! ClearcalcActor ! Num(13.0)calcActor ! Mul(1.5)implicit val timeout = akka.util.Timeout(1 second)((calcActor ? GetResult).mapTo[String]) foreach printlnscala.io.StdIn.readLine()calcActor ! Div(0.0)calcActor ! Div(1.5)calcActor ! Add(100.0)((calcActor ? GetResult).mapTo[String]) foreach printlnscala.io.StdIn.readLine()localSystem.terminate()}

從代碼上看構建calculator（SupervisorActor）過程與普通的Actor構建沒分別，所有細節都放在配置文件里了。但是，要注意actorOf的name必須與配置文檔中的設置匹配。

試運行結果與上一個例子相同。值得注意的是實際遠程構建的是一個SupervisorActor。Calculator的構建是SupervisorActor構建的其中一部分。從運算結果看：這個SupervisorActor也實現了它的功能。

下面是這次示范的源代碼：

?local/build.sbt

azy val commonSettings = seq (name := "RemoteCreateDemo",version := "1.0",scalaVersion := "2.11.8",libraryDependencies := Seq("com.typesafe.akka" %% "akka-actor" % "2.5.2","com.typesafe.akka" %% "akka-remote" % "2.5.2") )lazy val local = (project in file(".")).settings(commonSettings).settings(name := "remoteCreateDemo").aggregate(calculator).dependsOn(calculator)lazy val calculator = (project in file("calculator")).settings(commonSettings).settings(name := "calculator")lazy val remote = (project in file("remote")).settings(commonSettings).settings(name := "remoteSystem").aggregate(calculator).dependsOn(calculator)

calculator/calculator.scala

package remoteCreation.calculatorimport akka.actor._ import scala.concurrent.duration._object Calcultor {sealed trait MathOpscase class Num(dnum: Double) extends MathOpscase class Add(dnum: Double) extends MathOpscase class Sub(dnum: Double) extends MathOpscase class Mul(dnum: Double) extends MathOpscase class Div(dnum: Double) extends MathOpssealed trait CalcOpscase object Clear extends CalcOpscase object GetResult extends CalcOpsdef props = Props(new Calcultor)def supervisorProps = Props(new SupervisorActor) }class Calcultor extends Actor with ActorLogging {import Calcultor._var result: Double = 0.0 //internal stateoverride def receive: Receive = {case Num(d) => result = dcase Add(d) => result += dcase Sub(d) => result -= dcase Mul(d) => result *= dcase Div(d) =>val _ = result.toInt / d.toInt //yield ArithmeticExceptionresult /= dcase Clear => result = 0.0case GetResult =>sender() ! s"Result of calculation is: $result"}override def preRestart(reason: Throwable, message: Option[Any]): Unit = {log.info(s"Restarting calculator: ${reason.getMessage}")super.preRestart(reason, message)} }class SupervisorActor extends Actor {def decider: PartialFunction[Throwable,SupervisorStrategy.Directive] = {case _: ArithmeticException => SupervisorStrategy.Resume}override def supervisorStrategy: SupervisorStrategy =OneForOneStrategy(maxNrOfRetries = 5, withinTimeRange = 5 seconds){decider.orElse(SupervisorStrategy.defaultDecider)}val calcActor = context.actorOf(Calcultor.props,"calculator")override def receive: Receive = {case msg@ _ => calcActor.forward(msg)}}

remote/src/main/resources/application.conf

akka {actor {provider = remote}remote {enabled-transports = ["akka.remote.netty.tcp"]netty.tcp {hostname = "127.0.0.1"port = 2552}log-sent-messages = onlog-received-messages = on} }

remote/CalculatorRunner.scala

package remoteCreation.remote import com.typesafe.config.ConfigFactory import akka.actor._object CalculatorRunner extends App {val remoteSystem = ActorSystem("remoteSystem",ConfigFactory.load("application"))println("Remote system started.")scala.io.StdIn.readLine()remoteSystem.terminate()}

local/src/main/resources/application.conf

akka {actor {provider = remote,deployment {"/calculator" {remote = "akka.tcp://remoteSystem@127.0.0.1:2552"}}}remote {netty.tcp {hostname = "127.0.0.1",port=2554}} }

local/RemotingCreation.scala

import akka.actor._ import remoteCreation.calculator.Calcultor._ import scala.concurrent.duration._ import akka.pattern._object RemotingCreate extends App {val localSystem = ActorSystem("localSystem")val calcActor = localSystem.actorOf(props,name = "calculator") //created SupervisorActor import localSystem.dispatchercalcActor ! ClearcalcActor ! Num(13.0)calcActor ! Mul(1.5)implicit val timeout = akka.util.Timeout(1 second)((calcActor ? GetResult).mapTo[String]) foreach printlnscala.io.StdIn.readLine()calcActor ! Div(0.0)calcActor ! Div(1.5)calcActor ! Add(100.0)((calcActor ? GetResult).mapTo[String]) foreach printlnscala.io.StdIn.readLine()localSystem.terminate()}

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轉載于:https://www.cnblogs.com/tiger-xc/p/7063301.html

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