Akka 实践之(三) 远程部署
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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)
- <span style="font-family:Microsoft YaHei;font-size:14px;"> final String path = "akka.tcp://CalculatorSystem@127.0.0.1:8552/user/calculator";
- final ActorRef actor = system.actorOf( Props.create(LookupActor.class, path), "lookupActor");</span>
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。- <span style="font-family:Microsoft YaHei;font-size:14px;">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<Object> active = new Procedure<Object>() {
- @Override
- public void apply(Object message) {
- if (message instanceof Op.MathOp) {
-
- calculator.tell(message, getSelf());
-
- } else if (message instanceof Op.AddResult) {
- Op.AddResult result = (Op.AddResult) message;
- System.out.printf("Add result: %d + %d = %d\n", result.getN1(),
- result.getN2(), result.getResult());
-
- } else if (message instanceof Op.SubtractResult) {
- Op.SubtractResult result = (Op.SubtractResult) message;
- System.out.printf("Sub result: %d - %d = %d\n", result.getN1(),
- result.getN2(), result.getResult());
-
- } else if (message instanceof Terminated) {
- System.out.println("Calculator terminated");
- sendIdentifyRequest();
- getContext().unbecome();
-
-
-
- } else if (message instanceof ReceiveTimeout) {
-
-
- } else {
- unhandled(message);
- }
-
- }
- };
- }
- </span>
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。
- <span style="font-family:Microsoft YaHei;font-size:14px;">package com.cwqsolo.study.akka.demo;
- import static java.util.concurrent.TimeUnit.SECONDS;
-
- import java.util.Random;
-
-
-
-
-
- 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() {
- <span style="color:#ff0000;"> final ActorSystem system = ActorSystem.create("CalculatorSystem",
- ConfigFactory.load(("calculator")));</span>
- <span style="color:#ff0000;">final ActorRef calActor = system.actorOf(Props.create(CalculatorActor.class), "calculator");</span>
-
- System.out.println("Started CalculatorSystem");
- }
-
- public static void startRemoteLookupSystem() {
-
- <span style="color:#ff0000;">final ActorSystem system = ActorSystem.create("LookupSystem",
- ConfigFactory.load("remotelookup"));</span>
- <span style="color:#ff0000;"> final String path = "akka.tcp://CalculatorSystem@127.0.0.1:8552/user/calculator";
- final ActorRef actor = system.actorOf(
- Props.create(LookupActor.class, path), "lookupActor");</span>
-
- 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());
-
- }
- }</span>
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
- <span style="font-family:Microsoft YaHei;font-size:14px;">[root@archive akka]# cat common.conf
- akka {
- actor {
- provider = "akka.remote.RemoteActorRefProvider"
- }
-
- remote {
- enabled-transports = ["akka.remote.netty.tcp"]
- netty.tcp {
- hostname = "127.0.0.1"
- }
- }
- }</span>
- <span style="font-family:Microsoft YaHei;font-size:14px;">[root@archive akka]# cat calculator.conf
- include "common"
-
- akka {
- # LISTEN on tcp port 2552
- remote.netty.tcp.port = 8552
- } </span>
- <span style="font-family:Microsoft YaHei;font-size:14px;">[root@archive akka]# cat remotelookup.conf
- include "common"
-
- akka {
- remote.netty.tcp.port = 2553
- }</span>
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。
- <span style="font-family:Microsoft YaHei;font-size:14px;">[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)
- </span>
或者是这样
- <span style="font-family:Microsoft YaHei;font-size:14px;">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)
- </span>
最后通过只打包自己的代码, lib库单独放置的方式解决