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Akka 可以支持客户端和服务端远程部署，这点对与高并发分布式调用非常有利。 在上篇的代码基础上，新增2个类，LookupActor和LookupApplication.java
1、首先看一下类图
2、 源码
在本例中，将远程创建CalculatorActor 对象，然后通过指定path的方式创建这个对象的远程Actor（其实我认为是这个对象的代理）
final String path = "akka.tcp://CalculatorSystem@127.0.0.1:8552/user/calculator"; final ActorRef actor = system.actorOf( Props.create(LookupActor.class, path), "lookupActor"); LookupActor和 LookupApplication的源码如下，重点关注是如何创建远程对象，以及如何获取对远程对象的使用。 package com.cwqsolo.study.akka.demo;import static java.util.concurrent.TimeUnit.SECONDS;import scala.concurrent.duration.Duration;import akka.actor.ActorRef;import akka.actor.ActorIdentity;import akka.actor.Identify;import akka.actor.Terminated;import akka.actor.UntypedActor;import akka.actor.ReceiveTimeout;import akka.japi.Procedure;public class LookupActor extends UntypedActor { private final String path; private ActorRef calculator = null; public LookupActor(String path) { this.path = path; sendIdentifyRequest(); } private void sendIdentifyRequest() { getContext().actorSelection(path).tell(new Identify(path), getSelf()); getContext() .system() .scheduler() .scheduleOnce(Duration.create(3, SECONDS), getSelf(), ReceiveTimeout.getInstance(), getContext().dispatcher(), getSelf()); } @Override public void onReceive(Object message) throws Exception { if (message instanceof ActorIdentity) { calculator = ((ActorIdentity) message).getRef(); if (calculator == null) { System.out.println("Remote actor not available: " + path); } else { getContext().watch(calculator); getContext().become(active, true); } } else if (message instanceof ReceiveTimeout) { sendIdentifyRequest(); } else { System.out.println("Not ready yet"); } } Procedure 可以看到LookupActor 与上节中的CreationActor类没有什么区别，重点是LookupApplication类源码。 package com.cwqsolo.study.akka.demo;import static java.util.concurrent.TimeUnit.SECONDS;import java.util.Random;//import scala.concurrent.duration.Duration;//import akka.actor.ActorRef;//import akka.actor.ActorSystem;//import akka.actor.Props;import com.typesafe.config.ConfigFactory;import java.util.Arrays; import java.util.concurrent.Callable; import scala.concurrent.*;import scala.concurrent.duration.Duration;import akka.actor.ActorRef; import akka.actor.ActorSystem; import akka.actor.Props; public class LookupApplication { public static void main(String[] args) { if (args.length == 0 || args[0].equals("Calculator")) startRemoteCalculatorSystem(); if (args.length == 0 || args[0].equals("Lookup")) startRemoteLookupSystem(); } public static void startRemoteCalculatorSystem() { final ActorSystem system = ActorSystem.create("CalculatorSystem", ConfigFactory.load(("calculator"))); final ActorRef calActor = system.actorOf(Props.create(CalculatorActor.class), "calculator"); //calActor. System.out.println("Started CalculatorSystem"); } public static void startRemoteLookupSystem() { final ActorSystem system = ActorSystem.create("LookupSystem", ConfigFactory.load("remotelookup")); final String path = "akka.tcp://CalculatorSystem@127.0.0.1:8552/user/calculator"; final ActorRef actor = system.actorOf( Props.create(LookupActor.class, path), "lookupActor"); System.out.println("Started LookupSystem"); final Random r = new Random(); system.scheduler().schedule(Duration.create(1, SECONDS), Duration.create(1, SECONDS), new Runnable() { @Override public void run() { if (r.nextInt(100) % 2 == 0) { actor.tell(new Op.Add(r.nextInt(100), r.nextInt(100)), null); } else { actor.tell(new Op.Subtract(r.nextInt(100), r.nextInt(100)), null); } } }, system.dispatcher()); }} 标红代码这里要注意，这里是关键，而且可以看到，这里用到了配置文件（一开始，这里没有搞懂，运行起来都是无法找到远程对象） 配置文件有3个
common.conf
[root@archive akka]# cat common.confakka { actor { provider = "akka.remote.RemoteActorRefProvider" } remote { enabled-transports = ["akka.remote.netty.tcp"] netty.tcp { hostname = "127.0.0.1" } } } [root@archive akka]# cat calculator.confinclude "common" akka { # LISTEN on tcp port 2552 remote.netty.tcp.port = 8552 }
[root@archive akka]# cat remotelookup.conf include "common"akka { remote.netty.tcp.port = 2553} 从上面的配置文件可以看到， calculator对象在8552端口进行监听， lookup对象通过remotelookup创建了 2553端口的监听，lookup对象通过path 获取 到calculator对象的引用（代理），然后就可以进行对象间的调用。
3、执行结果
[root@archive akka]# sh ./start.sh java version "1.7.0_80" Java(TM) SE Runtime Environment (build 1.7.0_80-b15) Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode) [INFO] [10/27/2016 16:48:26.956] [main] [Remoting] Starting remoting [INFO] [10/27/2016 16:48:27.234] [main] [Remoting] Remoting started; listening on addresses :[akka.tcp://CalculatorSystem@127.0.0.1:8552] [INFO] [10/27/2016 16:48:27.236] [main] [Remoting] Remoting now listens on addresses: [akka.tcp://CalculatorSystem@127.0.0.1:8552] Started CalculatorSystem [INFO] [10/27/2016 16:48:27.311] [main] [Remoting] Starting remoting [INFO] [10/27/2016 16:48:27.339] [main] [Remoting] Remoting started; listening on addresses :[akka.tcp://LookupSystem@127.0.0.1:2553] [INFO] [10/27/2016 16:48:27.339] [main] [Remoting] Remoting now listens on addresses: [akka.tcp://LookupSystem@127.0.0.1:2553] Started LookupSystem Calculating 9 - 61 Sub result: 9 - 61 = -52 Calculating 51 - 86 Sub result: 51 - 86 = -35 Calculating 64 - 30 Sub result: 64 - 30 = 34 Calculating 38 + 71 Add result: 38 + 71 = 109 Calculating 51 - 73 Sub result: 51 - 73 = -22 Calculating 29 + 12 Add result: 29 + 12 = 41
4、注意内容
4.1 因为引入了配置文件，需要使用google的配置文件类protobuf-java-2.5.0.jar
4.2 打包运行
我是eclipse环境中调试后，放centos执行的，一开始把代码和依赖库打包在一起，执行会报错。最后是将依赖库单独在centos上建一个lib，只打包代码部分，这样执行才没有问题。
[root@archive akka]# Exception in thread "main" com.typesafe.config.ConfigException$Missing: No configuration setting found for key 'akka.version' at com.typesafe.config.impl.SimpleConfig.findKey(SimpleConfig.java:124) at com.typesafe.config.impl.SimpleConfig.find(SimpleConfig.java:145) 或者是这样
Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)[root@archive akka]# Exception in thread "main" java.lang.NoClassDefFoundError: scala/concurrent/ExecutionContext at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2625) at java.lang.Class.getMethod0(Class.java:2866) at java.lang.Class.getMethod(Class.java:1676) 最后通过只打包自己的代码， lib库单独放置的方式解决