大数据系列修炼：Scala课程102

核心内容：

1、Akka的生命周期从总体上而言分为3个部分：
1>Actor自身资源的初始化工作（prestart），在prestart方法中可以完成资源的初始化工作。类似于MapReduce中的setup方法。
2>Actor通过receive方法接受消息并进行消息的模式匹配处理。类似于MapReduce中的Map与reduce阶段。
3>进入stop后，停止对消息的处理，进行资源的清理工作。类似于MapReduce中的cleanup阶段。

2、Actor之间是通过发消息的方式来进行沟通的，而一个Actor之所以能够给另外一个Actor发送消息，是因为握住了另外一个Actor邮箱的句柄，
而从Akka的角度讲，则为Address的地址。

3、一个Actor想让另外一个Actor做事情或者改变另外一个Actor的状态，只有通过发消息的方式。

4、Actor是构建Akka程序的核心基石，在Akka中，通过Actor可以帮我们构建可伸缩的、可分布式的、以及容错的应用程序。
Actor是异步的，非阻塞的，即Actor发送消息的过程是一个Synchronized的过程。

实例程序1:Actor通过receive偏函数不断循环自己的邮箱，并进行消息的匹配处理。

  override  def receive: Receive =  //在函数当中进行模式匹配对消息进行相应的处理
  {
    case message:String => mapActor ! message
    case message:Result => aggregateActor ! message
    case _ =>  //不对消息进行任何的处理
  }

实例程序2：下面是我自己另外写的程序,但是程序总是报错，没办法！

object  HelloAkka
{
  def main(args:Array[String]):Unit =
  {
      val system: ActorSystem = ActorSystem("HelloAkka2") //创建一个ActorSystem
      var master =  system.actorOf(Props[MasterApp],name = "MasterApp")

      master.tell("Spark and Hadoop")  //main方法所在的Actor给masterActor发送消息
      master.tell("Scala and Java" )    //在消息发送的过程中是一个synchronized的过程,要么全发，要么什么也不发。
      master.tell(20.0)

      Thread.sleep(5000)
      system.shutdown()
  }
}
class  MasterApp  extends Actor
{
  override def receive=  //不断循环自己的邮箱,并进行消息的模式匹配
  {
    case msg:String => println("Spark")
    case msg:Double => println("Hadoop")
    case _ =>
  }
}

结果：
"C:\Program Files (x86)\Java\jdk1.8.0_65\bin\java" -Didea.launcher.port=7536 "-Didea.launcher.bin.path=E:\Smart IDEA\IntelliJ IDEA Community Edition 2016.2.4\bin" -Dfile.encoding=UTF-8 -classpath "C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\charsets.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\deploy.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\access-bridge-32.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\cldrdata.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\dnsns.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\jaccess.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\jfxrt.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\localedata.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\nashorn.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\sunec.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\sunjce_provider.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\sunmscapi.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\sunpkcs11.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\ext\zipfs.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\javaws.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\jce.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\jfr.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\jfxswt.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\jsse.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\management-agent.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\plugin.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\resources.jar;C:\Program Files (x86)\Java\jdk1.8.0_65\jre\lib\rt.jar;E:\HelloScala\out\production\HelloTest;D:\SOFTWARE\scala\lib\scala-actors-migration.jar;D:\SOFTWARE\scala\lib\scala-actors.jar;D:\SOFTWARE\scala\lib\scala-library.jar;D:\SOFTWARE\scala\lib\scala-reflect.jar;D:\SOFTWARE\scala\lib\scala-swing.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\scala-library.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-actor-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-actor-migration-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-agent-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-beanstalk-mailbox-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-file-mailbox-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-kernel-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-mailboxes-common-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-mongo-mailbox-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-redis-mailbox-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-remote-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-sample-fsm-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-sample-hello-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-sample-hello-kernel-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-sample-remote-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-slf4j-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-testkit-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-transactor-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-zeromq-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\akka-zookeeper-mailbox-2.0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\beanstalk_client-1.4.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\bson-driver_2.9.0-1-0.2.9-1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\commons-codec-1.4.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\commons-io-1.4.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\commons-io-2.0.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\commons-logging-1.1.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\commons-pool-1.5.6.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\config-0.3.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\dispatch-json_2.9.1-0.8.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\h2-lzf-1.0.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\httpclient-4.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\httpcore-4.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\jna-3.0.9.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\jnr-constants-0.8.2.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\log4j-1.2.14.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\mongo-driver_2.9.0-1-0.2.9-1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\mongo-java-driver-2.7.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\netty-3.5.4.Final.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\objenesis-1.2.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\protobuf-java-2.4.1.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\redisclient_2.9.1-2.4.0.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\scala-stm_2.9.1-0.5.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\scalaj-collection_2.9.0-1-1.2.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\sjson_2.9.1-0.15.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\slf4j-api-1.6.4.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\util-core-1.12.2.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\zeromq-scala-binding_2.9.1-0.0.6.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\zkclient-0.3.jar;D:\SOFTWARE\akka\akka-2.0.5\lib\akka\zookeeper-3.4.0.jar;E:\Smart IDEA\IntelliJ IDEA Community Edition 2016.2.4\lib\idea_rt.jar" com.intellij.rt.execution.application.AppMain com.test.scala.app.HelloAkka2
Exception in thread "main" java.lang.NoSuchMethodError: scala.Predef$.augmentString(Ljava/lang/String;)Lscala/collection/immutable/StringOps;
    at akka.util.Duration$.(Duration.scala:76)
    at akka.util.Duration$.(Duration.scala)
    at akka.actor.ActorSystem$Settings.(ActorSystem.scala:140)
    at akka.actor.ActorSystemImpl.(ActorSystem.scala:449)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:111)
    at akka.actor.ActorSystem$.apply(ActorSystem.scala:93)
    at com.test.scala.app.HelloAkka2$.main(HelloAkka.scala:22)
    at com.test.scala.app.HelloAkka2.main(HelloAkka.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

Process finished with exit code 1

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