Akkahttp and servlet文档格式.docx

Akkahttp and servlet文档格式.docx

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importjava.util.logging.Level;

importjava.util.logging.Logger;

importjavax.servlet.AsyncContext;

importjavax.servlet.ServletException;

importjavax.servlet.annotation.WebServlet;

importjavax.servlet.http.HttpServlet;

importjavax.servlet.http.HttpServletRequest;

importjavax.servlet.http.HttpServletResponse;

@WebServlet（urlPatterns="

/test/async"

asyncSupported=true）

publicclassTestAsyncServletextendsHttpServlet{

privateExecutorexecutor;

@Override

publicvoidinit（）throwsServletException{

executor=Executors.newFixedThreadPool（30）;

}

protectedvoiddoGet（HttpServletRequestreq,HttpServletResponseresp）

throwsServletException,IOException{

finalAsyncContextasyncContext=req.startAsync（）;

executor.execute（newRunnable（）{

publicvoidrun（）{

HttpServletResponseresp=（HttpServletResponse）asyncContext.getResponse（）;

resp.setContentType（"

text/plain"

）;

try（PrintWriterwriter=resp.getWriter（））{

writer.print（"

Ok"

}catch（IOExceptionex）{

Logger.getLogger（TestAsyncServlet.class.getName（））.log（Level.SEVERE,null,ex）;

asyncCplete（）;

}）;

}

Fixedthreadpoolisusedtoprocessrequestsinbackgroundandresponseiswrittendirectlyfromthethreadofthisthreadpoolwhenitisready.

ThismodelgivesyouanabilitytointegratewithsuchframeworksasAkka.Seeexamplebelow.

importakka.actor.ActorRef;

importakka.actor.ActorSystem;

importakka.actor.Props;

importakka.actor.ReceiveTimeout;

importakka.actor.Terminated;

importakka.actor.UntypedActor;

importscala.concurrent.duration.Duration;

/test/akka"

publicclassTestAkkaServletextendsHttpServlet{

finalActorSystemsystem=（ActorSystem）req.getServletContext（）

.getAttribute（"

ActorSystem"

system.actorOf（Props.create（AskActor.class,asyncContext））;

staticclassTestActorextendsUntypedActor{

publicvoidonReceive（Objectmsg）throwsException{

if（msg=="

Test!

!

"

）{

getSender（）.tell（"

getSelf（））;

}else{

unhandled（msg）;

staticclassAskActorextendsUntypedActor{

finalprivateAsyncContextasyncContext;

publicAskActor（AsyncContextasyncContext）{

this.asyncContext=asyncContext;

ActorReftestActor=getContext（）

.actorOf（Props.create（TestActor.class）,"

TestActor"

getContext（）.watch（testActor）;

getContext（）.setReceiveTimeout（Duration.create（"

5seconds"

））;

testActor.tell（"

publicvoidonReceive（Objectmsg）throwsIOException{

if（msginstanceofReceiveTimeout）{

getContext（）.stop（getSelf（））;

resp.sendError（HttpServletResponse.SC_INTERNAL_SERVER_ERROR,

"

Timeout"

}elseif（msginstanceofTerminated）{

UnexpectedlyStopped"

}elseif（msginstanceofString）{

Theworkflowisthefollowing.

•doGet（）usesActorSystemtocreateanactoroftype 

AskActorwhichwillbetherootofsupervisionsubtreededicatedtoprocessthisrequest.See 

WhatSupervisionMeans.

•AskActorcreatesaninstanceofTestActorandsendsamessagetoit.MeanwhileitiswatchingtheTestActorinstanceandincaseitterminatesforsomereason 

AskActorwillreceive 

Terminatedmessage.WealsosettimeoutthatmeansifthereisnoresponsefromTestActorinspecifiedamountoftimeAskActorwillgetReceiveTimeoutmessage.

•TestActorreceivesmessagefromAskActor,processesitandsendsaresponse.

•AskAc