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Akka2使用探索7——“雲計算”示例（Actor、Future、Remoting、Router、Deploy、異步、併發使用Demo）
假設有一個很耗時的運算，單臺機器已經沒法滿足需求，這時你可以想到由多臺計算機協作完成。具體怎麼做呢。
舉個很簡單的例子，假設這個耗時的運算是從1加到100000，你現在有兩臺服務器，可以讓這兩臺服務器分別完成從1加到50000，和從50001加到100000，然後本機完成這兩個結果之和。
兩臺服務器分別啓動兩個akka Server，同時還有一個CalcActor。這個計算actor接收兩個參數：Integer start和Integer end，可以從start一直加到end，最後將結果返回給發送者：getSender().tell(result)。
@Log4j class CalcActor extends UntypedActor { @Override void onReceive(Object message) { log.debug "CalcActor received: ${message}----self:${getSelf()},sender:${getSender()}" if (message instanceof String) { String[] args = message.split(",") int start = Integer.parseInt(args[0]) int end = Integer.parseInt(args[1]) double result = 0d println("start calc:" + start + " upto " + end) start.upto(end) { result += it } sleep(5000) //模擬還要額外耗時5秒 println("result:" + result) getSender().tell(result) } else { unhandled(message) } } }
兩個服務器分別爲：
AkkaServerApp serverA = new AkkaServerApp("sc", "10.68.3.122", 8888, "calc") //AkkaSystemName爲sc，ip爲10.68.3.122，端口爲8888，serviceName爲calc。 AkkaServerApp serverA = new AkkaServerApp("sp", "10.68.3.124", 8888, "calc")//AkkaSystemName爲sp，ip爲10.68.3.124，端口爲8888，serviceName爲calc。
主要的代碼在客戶端：
public static void main(String[] args) throws Exception { final AkkaServerApp app = new AkkaServerApp("xwc", "127.0.0.1", 6666, "client");//客戶端akka配置 ActorRef remoteCalcA1 = app.getSystem().actorOf(new Props(CalcActor.class)..withDeploy(new Deploy(new RemoteScope(new Address("akka", "sc", "10.68.3.122", 8888)))), "clientCalcA1");//將CalcActor發佈到遠程10.68.3.122上 ActorRef remoteCalcA2 = app.getSystem().actorOf(new Props(CalcActor.class)..withDeploy(new Deploy(new RemoteScope(new Address("akka", "sc", "10.68.3.122", 8888)))), "clientCalcA2");//將CalcActor發佈到遠程10.68.3.124上 final List<Future<Double>> frs = new ArrayList<Future<Double>>();//異步返回結果Future存放在list中 //tell只請求，是否響應它完全不知道。ask是請求，並明確知道未來會相應。 // remoteCalcA.tell("1,10000", app.getServerActor()); // remoteCalcB.tell("10001,20000", app.getServerActor()); Future f1 = akka.pattern.Patterns.ask(remoteCalcA1, "1,50000", 150000);//讓遠程122計算從1加到50000，超時時間爲150秒 Future f2 = akka.pattern.Patterns.ask(remoteCalcA1, "50001,100000", 150000);//併發地讓遠程124計算從50001加到100000，超時時間150秒 frs.add(f1); frs.add(f2); Future<Iterable<Double>> future = Futures.sequence(frs, app.getSystem().dispatcher());將未來返回的結果轉換成Future<Iterable<Double>> Future<Double> fr = future.map(new Mapper<Iterable<Double>, Double>() { @Override public Double apply(Iterable<Double> parameter) { Double result = 0d; for (Double s : parameter) {//計算兩個服務器返回的結果 result += s; } return result; } }); fr.onSuccess(new OnSuccess<Double>() { @Override public void onSuccess(Double result) { System.out.println("雲計算返回結果-----" + result); } }); }
還可以讓服務器併發處理：把給從1加到50000的任務分成5個線程並行處理：1..10000,10001..20000,20001..30000,30001..40000,40001..50000，這樣能更好地提高效率。
如果按上面的方法僅僅是發佈多個remote actor：
ActorRef remoteCalcAn = app.getSystem().actorOf(new Props(CalcActor.class)..withDeploy(new Deploy(newRemoteScope(new Address("akka", "sc", "10.68.3.122", 8888)))), "clientCalcAn");
是沒法提高效率的，因爲這時的CalcActor是單線程的，它只會先接收1..10000，處理完後再接收10001..20000並處理。。。。。
使其能夠並行處理很簡單，創建remoteActor時加上withRoute即可：
ActorRef remoteCalcAn = app.getSystem().actorOf(new Props(CalcActor.class).withRouter(new RoundRobinRouter(5)).withDeploy(new Deploy(new RemoteScope(new Address("akka", "sc", "10.68.3.122", 8888)))), "clientCalcAn"); //RoundRobinRouter的參數5可以理解爲分配5個線程並行處理
代碼跟上面基本相同
public static void main(String[] args) throws Exception { final AkkaServerApp app = new AkkaServerApp("xwc", "127.0.0.1", 6666, "client"); ActorRef remoteCalcA1 = app.getSystem().actorOf(new Props(CalcActor.class).withRouter(new RoundRobinRouter(4)).withDeploy(new Deploy(new RemoteScope(new Address("akka", "sc", "10.68.3.122", 8888)))), "clientCalcA1"); ActorRef remoteCalcB1 = app.getSystem().actorOf(new Props(CalcActor.class).withRouter(new RoundRobinRouter(4)).withDeploy(new Deploy(new RemoteScope(new Address("akka", "sp", "10.68.3.124", 8888)))), "clientCalcB1"); final List<Future<Double>> frs = new ArrayList<Future<Double>>(); Future f1 = akka.pattern.Patterns.ask(remoteCalcA1, "1,10000", 150000); Future f2 = akka.pattern.Patterns.ask(remoteCalcA1, "10001,20000", 150000); Future f3 = akka.pattern.Patterns.ask(remoteCalcA1, "20001,30000", 150000); Future f4 = akka.pattern.Patterns.ask(remoteCalcA1, "30001,40000", 150000); Future f5 = akka.pattern.Patterns.ask(remoteCalcB1, "40001,50000", 150000); Future f6 = akka.pattern.Patterns.ask(remoteCalcB1, "50001,60000", 150000); Future f7 = akka.pattern.Patterns.ask(remoteCalcB1, "60001,70000", 150000); Future f8 = akka.pattern.Patterns.ask(remoteCalcB1, "70001,80000", 150000); frs.add(f1); frs.add(f2); frs.add(f3); frs.add(f4); frs.add(f5); frs.add(f6); frs.add(f7); frs.add(f8); Future<Iterable<Double>> future = Futures.sequence(frs, app.getSystem().dispatcher()); Future<Double> fr = future.map(new Mapper<Iterable<Double>, Double>() { @Override public Double apply(Iterable<Double> parameter) { Double result = 0d; for (Double s : parameter) { result += s; } return result; } }); fr.onSuccess(new OnSuccess<Double>() { @Override public void onSuccess(Double result) { System.out.println("雲計算返回從1加到80000的結果-----" + result); } }); }