AKKA笔记2
1.Actor是个 scala写的接口
除了获取sender self recieve 其他的打眼一看面向切面的n多方法
其中： preStart 用于发送前初始化参数 postStop用于结束后回收资源
2. Actor sender ， self ， path 每个actor都有系统内唯一的一个path
master.tell("start", master);
path ： akka://test/user/master
Actor之间发送消息：
定义另一个 Actor1 和 Actor2
public class Actor1 extends UntypedActor{
@Override
public void onReceive(Object msg) throws Exception {
System.out.println(""+this.getClass().getSimpleName()+"::sender:"+this.getSender());
if (msg instanceof String){
String s = (String) msg;
this.getSender().tell("akka.apply.actor.Actor2", this.getSelf());
}else
this.unhandled(msg);
}
}
public class Actor2 extends UntypedActor{
@Override
public void onReceive(Object msg) throws Exception {
System.out.println(""+this.getClass().getSimpleName()+"::sender:"+this.getSender());
if (msg instanceof String){
String s = (String) msg;
this.getSender().tell("akka.apply.actor.Actor1", this.getSelf());
}else
this.unhandled(msg);
}
}
修改 MasterActor : onReceive方法
@Override
public void onReceive(Object msg) throws Exception {
System.out.println(""+this.getClass().getSimpleName()+"::sender:"+this.getSender()+" ::self:"+this.getSelf());
//System.out.println(this.getSelf());
if (msg instanceof String){
if ( true)
return;
String s = (String) msg;
if ( s.equals("start")){
ActorRef a1 = this.getContext().actorOf(Props.create(Actor1.class), "Actor1");
ActorRef a2 = this.getContext().actorOf(Props.create(Actor2.class), "Actor2");
a1.tell("akka.apply.actor.Actor1", a2);
}
}else
this.unhandled(msg);
}
虽然启始消息是MasterActor的方法中定义发送的，但 a1.tell("akka.apply.actor.Actor1", a2); 定义了 接受方是 Actor1，发送方是 Actor2，（相当于master在方法中，发给a1一个消息，告诉a1，这个消息不是我发的是a1发的，虽然这个方式很灵活，但现在还不太理解这么设计的目的。）这两者又互相将消息发给对方，执行结果如下：
MasterActor::sender:Actor[akka://test/user/master#-2085464928] ::self:Actor[akka://test/user/master#-2085464928]
Actor1::sender:Actor[akka://test/user/master/Actor2#1627072295] ::self:Actor[akka://test/user/master/Actor1#-2006482622]
Actor2::sender:Actor[akka://test/user/master/Actor1#-2006482622] ::self:Actor[akka://test/user/master/Actor2#1627072295]
Actor1::sender:Actor[akka://test/user/master/Actor2#1627072295] ::self:Actor[akka://test/user/master/Actor1#-2006482622]
Actor2::sender:Actor[akka://test/user/master/Actor1#-2006482622] ::self:Actor[akka://test/user/master/Actor2#1627072295]
Actor1::sender:Actor[akka://test/user/master/Actor2#1627072295] ::self:Actor[akka://test/user/master/Actor1#-2006482622]
Actor2::sender:Actor[akka://test/user/master/Actor1#-2006482622] ::self:Actor[akka://test/user/master/Actor2#1627072295]
........
修改Actor1的方法，将消息发给MasterActor，
public void onReceive(Object msg) throws Exception {
System.out.println(""+this.getClass().getSimpleName()+"::sender:"+this.getSender()+" ::self:"+this.getSelf());
//System.out.println(this.getSelf());
if (msg instanceof String){
String s = (String) msg;
ActorRef m = this.getContext().actorOf(Props.create(MasterActor.class), "master");
m.tell("return Master", this.getSelf());
//this.getSender().tell("akka.apply.actor.Actor2", this.getSelf());
//this.getSelf().tell(s, getSender());
//ActorRef a = this.getContext().actorOf(Props.create( Class.forName(s)), s);
//a.tell(s, a);
//this.getContext().stop(a);
}else
this.unhandled(msg);
}
运行结果：
MasterActor::sender:Actor[akka://test/user/master#-1998415775] ::self:Actor[akka://test/user/master#-1998415775]
Actor1::sender:Actor[akka://test/user/master/Actor2#-63616032] ::self:Actor[akka://test/user/master/Actor1#-795382741]
MasterActor::sender:Actor[akka://test/user/master/Actor1#-795382741] ::self:Actor[akka://test/user/master/Actor1/master#2020933176]
发现MasterActor的path发生了变化，AKKA的Actor采用树结构，父类的Actor负责管理子类，当子类由于错误关闭，父类会重建子类发送消息（后面找机会验证一下）
停止消息
在MasterActor的onReceive方法中添加
this.getContext().stop(a1);
但发现并不是消息传递到Action1的时候 就会停止，而是会在Actor1 Actor2相互交互多次，而且次数不固定，说明这个停止是异步的。
