由于AKka的核心是Actor，而Actor是按照Actor模型进行实现的，所以在使用Akka之前，有必要弄清楚什么是Actor模型。

Actor模型最早是1973年Carl Hewitt、Peter Bishop和Richard Seiger的论文中出现的，受物理学中的广义相对论(general relativity)和量子力学(quantum mechanics)所启发，为解决并发计算的一个数学模型。

Actor模型所推崇的哲学是”一切皆是Actor“，这与面向对象编程的”一切皆是对象“类似。但不同的是，在模型中，Actor是一个运算实体，它遵循以下规则： 接受外部消息，不占用调用方（消息发送者）的CPU时间片 通过消息改变自身的状态 创建有限数量的新Actor 发送有限数量的消息给其他Actor 很多语言都实现了Actor模型，而其中最出名的实现要属Erlang的。Akka的实现借鉴了不少Erlang的经验。

<dependency><groupId>com.typesafe.akka</groupId><artifactId>akka-actor_2.11</artifactId><version>2.4.7</version>
</dependency>

tell 发送一个消息到目标Actor后立刻返回

public class C extends AbstractActor {@Overridepublic Receive createReceive() {return receiveBuilder().match(Object.class,obj->{if(obj instanceof String){System.out.println("C:  D你回复给我的消息我收到了！");return;}SomeOne someOne = (SomeOne) obj;System.out.println("C:  C接收到消息："+someOne.toString());// 创建D路由ActorRef actorRef = this.getContext().actorOf(Props.create(D.class, D::new));// 传递给DactorRef.tell(someOne,self());// 路由给D(和tell 实现的功能一样)//actorRef.forward(someOne,getContext());}).build();}public static void main(String[] args) {ActorSystem ok = ActorSystem.create("ok");ActorRef actorRef = ok.actorOf(Props.create(C.class, C::new));Scanner sc = new Scanner(System.in);System.out.print("请输入:");String s = sc.nextLine();actorRef.tell(new SomeOne(1,s,0),ActorRef.noSender());}
}public class D extends AbstractActor {@Overridepublic Receive createReceive() {return receiveBuilder().match(Object.class,obj->{SomeOne someOne = (SomeOne) obj;System.out.println("D:  D接收到C 传过来的消息："+someOne.toString());Thread.sleep(2000);sender().tell("D:  我再把消息发给你C",self());}).build();}
}

注意：
ActorSystem是一个较重的存在，一般一个应用里，只需要一个ActorSystem。
在同一个ActorySystem中，Actor不能重名。

ask 发送一个消息到目标Actor，并返回一个Future对象，可以通过该对象获取结果。但前提是目标Actor会有Reply才行，如果没有Reply，则抛出超时异常

public class A extends AbstractActor {// 接收到对象SomeOne@Overridepublic Receive createReceive() {return receiveBuilder().match(Object.class,obj ->{if(obj instanceof SomeOne){SomeOne someOne = (SomeOne) obj;System.out.println(" A 收到 SomeOne 对象:"+someOne.toString());someOne.setAge(someOne.getAge()+1);// 业务。。。Thread.sleep(1000);// 返回结果this.getSender().tell("xxx",getSelf());}}).build();}## Await 同步阻塞等待结果public static void main(String[] args) {//ActorSystem test = ActorSystem.create("test");ActorRef actorRefA = test.actorOf(Props.create(A.class, A::new));SomeOne someOne = new SomeOne(1,"哈哈哈ok",10);// 2 分钟超时Timeout timeout = new Timeout(Duration.create(2, TimeUnit.SECONDS));Future<Object> future = Patterns.ask(actorRefA, someOne, timeout); //ref,消息体,超时时间try {// Await 同步阻塞等待方式String reply = (String) Await.result(future, timeout.duration());System.out.println("回复的消息: " + reply);} catch (Exception e) {e.printStackTrace();}}

public class A extends AbstractActor {// 接收到对象SomeOne@Overridepublic Receive createReceive() {return receiveBuilder().match(Object.class,obj ->{if(obj instanceof SomeOne){SomeOne someOne = (SomeOne) obj;System.out.println(" A 收到 SomeOne 对象:"+someOne.toString());someOne.setAge(someOne.getAge()+1);// 业务。。。Thread.sleep(1000);// 返回结果this.getSender().tell("xxx",getSelf());}}).build();}## future 异步等待结果。
public static void main(String[] args) {//ActorSystem test = ActorSystem.create("test");ActorRef actorRefA = test.actorOf(Props.create(A.class, A::new));SomeOne someOne = new SomeOne(1,"哈哈哈ok",10);// 2 分钟超时Timeout timeout = new Timeout(Duration.create(2, TimeUnit.SECONDS));//ref,消息体,超时时间Future<Object> future = Patterns.ask(actorRefA, someOne, timeout);// 异步方式future.onComplete(new OnComplete<Object>() {@Overridepublic void onComplete(Throwable throwable, Object o) throws Throwable {if (throwable != null) {System.out.println("返回结果异常：" + throwable.getMessage());} else {System.out.println("返回消息：" + o);}}}, test.dispatcher());// 成功，执行过程future.onSuccess(new OnSuccess<Object>() {@Overridepublic void onSuccess(Object msg) throws Throwable {System.out.println("回复的消息：" + msg);}}, test.dispatcher());//失败，执行过程future.onFailure(new OnFailure() {@Overridepublic void onFailure(Throwable throwable) throws Throwable {if (throwable instanceof TimeoutException) {System.out.println("服务超时");} else {System.out.println("未知错误");}}}, test.dispatcher());}

tell 前置后置处理，销毁线程 的例子

public class MessageSendAndAccept extends AbstractActor {//接收消息前置处理@Overridepublic void preStart() {System.out.println("--------- 接收到消息  start");}//接收消息后置处理@Overridepublic void postStop(){System.out.println("--------- 消息处理完毕  end");}// A接收消息@Overridepublic Receive createReceive() {return receiveBuilder().match(String.class,result ->{consoleLog(result);}).build();}//打印public void consoleLog(String log){System.out.println("接收到内容："+log);//销毁线程getContext().stop(self());}public static void main(String[] args) {// 创建ActorSystem仓库ActorSystem actorSystem = ActorSystem.create("demo");// 创建路由，路由到AActorRef my_actor = actorSystem.actorOf(Props.create(MessageSendAndAccept.class), "my_actor");// 给 A 发消息my_actor.tell("哈哈哈a",ActorRef.noSender());}
}

并发 执行方法 例子

创建多个actor 同时执行就好了

public class G extends AbstractActor {@Overridepublic Receive createReceive() {return receiveBuilder().match(Object.class,obj->{if(obj instanceof String){System.out.println(obj + ",time="+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())+"--- Thread ---"+Thread.currentThread().getName());//休眠 3sThread.sleep(3000L);System.out.println(Thread.currentThread().getName()+"---END");return;}}).build();}public static void main(String[] args) {ActorSystem ok = ActorSystem.create("ok");ActorRef actorRef_0 = ok.actorOf(Props.create(G.class, G::new));actorRef_0.tell("a",ActorRef.noSender());ActorRef actorRef_1 = ok.actorOf(Props.create(G.class, G::new));actorRef_1.tell("b",ActorRef.noSender());ActorRef actorRef_2 = ok.actorOf(Props.create(G.class, G::new));actorRef_2.tell("c",ActorRef.noSender());}
}