actor框架-Akka

一、简介

Akka的actor是对actor模型的实现，下面的例子中使用简单的demo说明akka的actor的用法(作为jar包使用，akka也可以作为单独的服务使用而且很强大)，akka的scala版本使用起来比较简洁，但是java版的就有点略显繁琐。

二、示例

1、maven配置：下载下来的jar包除了akka-actor还有依赖包scala-library和config

		<dependency>
			<groupId>com.typesafe.akka</groupId>
			<artifactId>akka-actor_2.10</artifactId>
			<version>2.2.4</version>
		</dependency>

import scala.Option;
import akka.actor.UntypedActor;

public class HelloWorld extends UntypedActor {
	@Override
	public void preStart() {
		System.out.println("===preStart");
	}
	@Override
	public void preRestart(Throwable reason, Option<Object> message) throws Exception {
		System.out.println("===preRestart");
		super.preRestart(reason, message);
	}
	@Override
	public void postRestart(Throwable reason) throws Exception {
		System.out.println("===postRestart");
		super.postRestart(reason);
	}
	@Override
	public void postStop() throws Exception {
		System.out.println("===postStop");
		super.postStop();
	}
	@Override
	public void onReceive(Object msg) {
		if (msg.toString().equals("hello")) {
			System.out.println("----" + msg);
			// getContext().stop(getSelf());
		} else {
			// 导致崩溃，actor会自动重启
			System.out.println(3 / 0);
			// unhandled(msg);
		}
	}
}

import akka.actor.ActorRef;
import akka.actor.ActorSelection;
import akka.actor.ActorSystem;
import akka.actor.Props;
import com.akka.actor.HelloWorld;
public class App {
	public static void main(String[] args) throws InterruptedException {
		ActorSystem system = ActorSystem.create("akka");
		ActorRef rcActor = system.actorOf(Props.create(HelloWorld.class), "helloWorld");
		rcActor.tell("hi", ActorRef.noSender());
		//Thread.sleep(3000);
		//Actor树
		ActorSelection as = system.actorSelection("/user/helloWorld");
		as.tell("hello", ActorRef.noSender());
	}
}

三、结果

===preStart
===preRestart
===postStop
===postRestart
===preStart
----hello
[ERROR] [03/17/2014 17:31:00.919] [akka-akka.actor.default-dispatcher-2] [akka://akka/user/helloWorld] / by zero
java.lang.ArithmeticException: / by zero ...  ....

启动时调用了preStart方法

因为消息处理导致崩溃，akka停止处理消息并自动重启(preRestart -->  preStart)

重启之后可以继续处理mailbox中的消息
输出的日志信息并不是异常出现的位置，是因为akka的日志处理本身也是交由actor(/system)处理，是异步的

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actor框架-Akka

原文：http://blog.csdn.net/sand_ant/article/details/21398563