本文概述
- Akka Actor发送消息
- Actor tell()方法示例
- Akka Actor tell()方法示例2
- 2)Akka Actor询问方法
- Akka Actor询问方法示例
- Akka Actor ask()方法示例2
- Akka Actor询问方法示例3
Akka Actor发送消息Akka提供了两个预定义的方法tell()和ask()进行消息交换。Actor可以通过以下方法将消息发送给另一个Actor。
1)Akka Actor tell()方法
【Akka Actor发送消息示例详解】它用于异步发送消息。它不会等待并阻止线程发送消息。它适用于” 忘火” 方法。你也可以使用！ (bang)感叹号发送消息。这是发送消息的首选方式。它提供了最佳的并发性和可伸缩性。
如果从Actor内部调用此方法, 则发送Actor的引用将与消息一起隐式传递。
如果从不是Actor的实例调用此方法, 则默认情况下, 发送者将是deadLetters actor引用。
Actor tell()方法示例
import akka.actor.{Actor, ActorSystem, Props};
class ActorExample extends Actor{
def receive = {
case message:String =>
println("Message received: "+message+ " from - "+ self.path.name);
println("sender:"+ sender());
// returns ActorRef
}
}object ActorExample{
def main(args:Array[String]){
val actorSystem = ActorSystem("ActorSystem");
val actor = actorSystem.actorOf(Props[ActorExample], "RootActor");
actor ! "Hello"// Sending message by using !
actor.tell("Hello", null);
// Sending message by using tell() method
// Sender is not passed here.
}
}输出
Message received: Hello from - RootActor
sender:Actor[akka://ActorSystem/deadLetters]// ActorRef refers to deadLetters
Message received: Hello from - RootActor
sender:Actor[akka://ActorSystem/deadLetters] // ActorRef refers to deadLettersAkka Actor tell()方法示例2
import akka.actor.{Actor, ActorSystem, Props};
class ActorExample extends Actor{
def receive = {
case message:String =>
println("Message received: "+message+ " from - "+ self.path.name);
println("Sender: "+sender())
var child = context.actorOf(Props[Actor2], "ChildActor");
child ! "Hello"}
}class Actor2 extends Actor{
def receive = {
case message:String =>
println("Message received: "+message+ " from - "+ self.path.name);
println("Sender: "+sender());
}
}object ActorExample{
def main(args:Array[String]){
val actorSystem = ActorSystem("ActorSystem");
val actor = actorSystem.actorOf(Props[ActorExample], "RootActor");
actor ! "Hello"
}
}输出
Message received: Hello from - RootActor
Sender: Actor[akka://ActorSystem/deadLetters] // Called from outside Actor
Message received: Hello from - ChildActor
Sender: Actor[akka://ActorSystem/user/RootActor#1451914889] // Called from within Actor2)Akka Actor询问方法在akka中, ask是一种模式, 涉及参与者和期货。 Ask用于异步发送消息, 它返回一个Future, 表示可能的答复。如果Actor没有回复并完成未来, 它将在超时期限后过期。超时时间过后, 它将引发TimeoutException。你可以使用其中一个吗？ (问号)或ask()发送消息。
如果你要响应, 则应始终倾向于使用Tell方法来提高性能, 而Ask方法则要优先。
Akka Actor询问方法示例
import akka.actor.{Actor, ActorSystem, Props};
import akka.util.Timeout;
import scala.concurrent.Await
import akka.pattern.ask
import scala.concurrent.duration._class ActorExample extends Actor{
def receive = {
case message:String =>
println("Message recieved: "+message);
}
}object ActorExample{
def main(args:Array[String]){
val actorSystem = ActorSystem("ActorSystem");
val actor = actorSystem.actorOf(Props[ActorExample], "RootActor");
implicit val timeout = Timeout(2 seconds);
val future = actor ? "Hello";
val result = Await.result(future, timeout.duration);
println(result);
}
}输出
Message recieved: Hello
Exception in thread "main" java.util.concurrent.TimeoutException: Futures timed out after [2 seconds]Akka Actor ask()方法示例2
import akka.actor.{Actor, ActorSystem, Props, ActorRef};
import akka.util.Timeout;
import scala.concurrent.Await
import akka.pattern.ask
import scala.concurrent.duration._class ActorExample extends Actor{
def receive = {
case message:String =>
println("Message received: "+message+" from outside actor instance");
println("Replaying");
val senderName = sender();
senderName ! "Hello, I got your message.";
// Replying message
}
}object ActorExample{
def main(args:Array[String]){
val actorSystem = ActorSystem("ActorSystem");
val actor = actorSystem.actorOf(Props[ActorExample], "RootActor");
implicit val timeout = Timeout(10 seconds);
val future = actor ? "Hello";
val result = Await.result(future, timeout.duration);
println("Message received: "+result);
}
}输出
Message received: Hello from outside actor instance
Replaying
Message received: Hello, I got your message.Akka Actor询问方法示例3
import akka.actor.{Actor, ActorSystem, Props};
import akka.util.Timeout;
import scala.concurrent.Await
import akka.pattern.ask
import scala.concurrent.duration._class ActorExample extends Actor{
def receive = {
case message:String =>
println("Message received: "+message+" from outside actor instance");
Thread.sleep(5000);
// actor thread is sleeping
println("Replaying");
val senderName = sender();
senderName ! "Hello, I got your message.";
// Replying message
}
}object ActorExample{
def main(args:Array[String]){
val actorSystem = ActorSystem("ActorSystem");
val actor = actorSystem.actorOf(Props[ActorExample], "RootActor");
implicit val timeout = Timeout(2 seconds);
val future = actor ? "Hello";
val result = Await.result(future, timeout.duration);
println("Message received: "+result);
}
}输出
Message received: Hello from outside actor instance
Exception in thread "main" java.util.concurrent.TimeoutException: Futures timed out after [2 seconds]推荐阅读
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