最近公司用到spary+akak，然后从官网找了一个入门的例子，现在分析一下

1.简单demo

首先akka给我的感觉就是一个异步的发送消息的机制，如果我用java来解释，那就是重新起一个新线程，然后调用一个类的方法。

//简单定义一些用到的消息类 object Greeter { //#greeter-messages def props(message: String, printerActor: ActorRef): Props = Props(new Greeter(message, printerActor)) //#greeter-messages final case class WhoToGreet(who: String) case object Greet } //继承Actor，实现receive方法，printerActor这也是个actor，这里省略 class Greeter(message: String, printerActor: ActorRef) extends Actor { import Greeter._ import Printer._ var greeting = "" def receive = { case WhoToGreet(who) => greeting = message + ", " + who case Greet => //#greeter-send-message printerActor ! Greeting(greeting) //#greeter-send-message } } //相当于主函数 object AkkaQuickstart extends App { import Greeter._ // Create the 'helloAkka' actor system val system: ActorSystem = ActorSystem("helloAkka") // Create the 'greeter' actors val howdyGreeter: ActorRef =system.actorOf(Greeter.props("Howdy", printer), "howdyGreeter") //#main-send-messages howdyGreeter ! WhoToGreet("Akka") howdyGreeter ! Greet } 

2. 分析！是什么

讯享网 / * Sends a one-way asynchronous message. E.g. fire-and-forget semantics. * <p/> * * If invoked from within an actor then the actor reference is implicitly passed on as the implicit 'sender' argument. * <p/> * * This actor 'sender' reference is then available in the receiving actor in the 'sender()' member variable, * if invoked from within an Actor. If not then no sender is available. * <pre> * actor ! message * </pre> * <p/> */ def !(message: Any)(implicit sender: ActorRef = Actor.noSender): Unit 

fire-and-forget：这个词很生动，也就说调用某个类方法的时候会把调用者的引用传递过去。

讯享网

3. 深入分析调用过程

一路调试过去，会发现调用Dispatcher这个类

protected[akka] override def registerForExecution( mbox: Mailbox, hasMessageHint: Boolean, hasSystemMessageHint: Boolean): Boolean = { if (mbox.canBeScheduledForExecution(hasMessageHint, hasSystemMessageHint)) { //This needs to be here to ensure thread safety and no races if (mbox.setAsScheduled()) { try { executorService.execute(mbox) true } catch { case _: RejectedExecutionException => try { executorService.execute(mbox) true } catch { //Retry once case e: RejectedExecutionException => mbox.setAsIdle() eventStream.publish(Error(e, getClass.getName, getClass, "registerForExecution was rejected twice!")) throw e } } } else false } else false } 

1. 其中mbox: Mailbox，消息参数、调用者参数都被封装到这个类中了，到底Mailbox是什么

讯享网private[akka] abstract class Mailbox(val messageQueue: MessageQueue) extends ForkJoinTask[Unit] with SystemMessageQueue with Runnable 

从中文解释就是一个邮箱，它带有队列功能(MessageQueue),同时它实现了Runnable 和ForkJoinTask，这个学习java的都很熟悉了，这个就是一个可运行的任务

2. executorService.execute(mbox)
   这个再熟悉不过了，这个就是线程服务，执行一个可运行的任务。

总结

akak就是一个异步的调用方法的东西，它还是利用java中的executorService来调用，算是一个队多线程的封装把