Akka 实践（二）- java开发demo1

柔光的暖阳◎ 2022-07-16 12:40 453阅读 0赞

下面就Akka的一个java demo来说明Akka 如何运作的。

# 1、首先下载 Akka的官方包 #

下载地址为： http://akka.io/downloads/.  我下载的是 Akka的2.3.15

![Center][]

解压这个压缩包，准备拷贝相关的jar包到自己的工程

# 2、创建一个java工程 #

首先导入包

![Center 1][]

#  3、下面是源码和源码说明 #

这里，首先贴入源码，然后再对源码进行分析。 源码有4个文件，主要完成的功能是，主程序创建ActorSystem，并且生成Actor1（CreationActor），这个Actor1，根据随机得到的消息，循环创建线程，每个线程都创建Actor2（CalculatorActor），并发不同的消息给Actor2 告诉这些第二层Actor要做什么。 这些Actor2 做完自己的事情后，发消息给Actor1,告诉自己完成了，Actor1 收到消息后，打印结果是什么，并结束线程。

整个业务大致可以用下面图来表示：（左边是示意图，右边是类图）

![Center 2][]

Op.java

package com.cwqsolo.study.akka.demo;
 
 import java.io.Serializable;
 
 //Op 类是操作类，分别包含了 加减乘除类和加减乘除结果类
 public class Op {
 
 public interface MathOp extends Serializable {
 }
 
 public interface MathResult extends Serializable {
 }
 
 //加法操作
 static class Add implements MathOp {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 
 public Add(int n1, int n2) {
 this.n1 = n1;
 this.n2 = n2;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 }
 
 static class AddResult implements MathResult {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 private final int result;
 
 public AddResult(int n1, int n2, int result) {
 this.n1 = n1;
 this.n2 = n2;
 this.result = result;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 
 public int getResult() {
 return result;
 }
 }
 
 //减法操作
 static class Subtract implements MathOp {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 
 public Subtract(int n1, int n2) {
 this.n1 = n1;
 this.n2 = n2;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 }
 
 static class SubtractResult implements MathResult {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 private final int result;
 
 public SubtractResult(int n1, int n2, int result) {
 this.n1 = n1;
 this.n2 = n2;
 this.result = result;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 
 public int getResult() {
 return result;
 }
 }
 
 //乘法操作
 static class Multiply implements MathOp {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 
 public Multiply(int n1, int n2) {
 this.n1 = n1;
 this.n2 = n2;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 }
 
 static class MultiplicationResult implements MathResult {
 private static final long serialVersionUID = 1L;
 private final int n1;
 private final int n2;
 private final int result;
 
 public MultiplicationResult(int n1, int n2, int result) {
 this.n1 = n1;
 this.n2 = n2;
 this.result = result;
 }
 
 public int getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 
 public int getResult() {
 return result;
 }
 }
 // 除法操作
 static class Divide implements MathOp {
 private static final long serialVersionUID = 1L;
 private final double n1;
 private final int n2;
 
 public Divide(double n1, int n2) {
 this.n1 = n1;
 this.n2 = n2;
 }
 
 public double getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 }
 
 static class DivisionResult implements MathResult {
 private static final long serialVersionUID = 1L;
 private final double n1;
 private final int n2;
 private final double result;
 
 public DivisionResult(double n1, int n2, double result) {
 this.n1 = n1;
 this.n2 = n2;
 this.result = result;
 }
 
 public double getN1() {
 return n1;
 }
 
 public int getN2() {
 return n2;
 }
 
 public double getResult() {
 return result;
 }
 }
 }

CalculatorActor.java

package com.cwqsolo.study.akka.demo;
 
 import akka.actor.UntypedActor;
 
 
 public class CalculatorActor extends UntypedActor {
 
 @Override
 public void onReceive(Object message) {
 
 if (message instanceof Op.Add) {
 Op.Add add = (Op.Add) message;
 System.out.println("Calculating " + add.getN1() + " + " + add.getN2());
 Op.AddResult result = new Op.AddResult(add.getN1(), add.getN2(),
 add.getN1() + add.getN2());
 getSender().tell(result, getSelf());
 
 } else if (message instanceof Op.Subtract) {
 Op.Subtract subtract = (Op.Subtract) message;
 System.out.println("Calculating " + subtract.getN1() + " - "
 + subtract.getN2());
 Op.SubtractResult result = new Op.SubtractResult(subtract.getN1(),
 subtract.getN2(), subtract.getN1() - subtract.getN2());
 getSender().tell(result, getSelf());
 
 } else if (message instanceof Op.Multiply) {
 Op.Multiply multiply = (Op.Multiply) message;
 System.out.println("Calculating " + multiply.getN1() + " * "
 + multiply.getN2());
 Op.MultiplicationResult result = new Op.MultiplicationResult(
 multiply.getN1(), multiply.getN2(), multiply.getN1()
 * multiply.getN2());
 getSender().tell(result, getSelf());
 
 } else if (message instanceof Op.Divide) {
 Op.Divide divide = (Op.Divide) message;
 System.out.println("Calculating " + divide.getN1() + " / "
 + divide.getN2());
 Op.DivisionResult result = new Op.DivisionResult(divide.getN1(),
 divide.getN2(), divide.getN1() / divide.getN2());
 getSender().tell(result, getSelf());
 
 } else {
 unhandled(message);
 }
 }
 }

CreationActor.java

package com.cwqsolo.study.akka.demo;
 
 import akka.actor.ActorRef;
 import akka.actor.Props;
 import akka.actor.UntypedActor;
 
 //创建Actor
 public class CreationActor extends UntypedActor {
 
 @Override
 public void onReceive(Object message) throws Exception {
 
 if (message instanceof Op.MathOp) {
 ActorRef calculator = getContext().actorOf(
 Props.create(CalculatorActor.class));
 calculator.tell(message, getSelf());
 
 } else if (message instanceof Op.MultiplicationResult) {
 Op.MultiplicationResult result = (Op.MultiplicationResult) message;
 System.out.printf("Mul result: %d * %d = %d\n", result.getN1(),
 result.getN2(), result.getResult());
 getContext().stop(getSender());
 
 } else if (message instanceof Op.DivisionResult) {
 Op.DivisionResult result = (Op.DivisionResult) message;
 System.out.printf("Div result: %.0f / %d = %.2f\n", result.getN1(),
 result.getN2(), result.getResult());
 getContext().stop(getSender());
 
 } else {
 unhandled(message);
 }
 }
 }

CreationApplication.java

package com.cwqsolo.study.akka.demo;
 
 import static java.util.concurrent.TimeUnit.SECONDS;
 import java.util.Random;
 import scala.concurrent.duration.Duration;
 import akka.actor.ActorRef;
 import akka.actor.ActorSystem;
 import akka.actor.Props;
 
 import com.typesafe.config.ConfigFactory;
 
 public class CreationApplication {
 
 public static void main(String[] args) {
 if (args.length == 0 || args[0].equals("CalculatorWorker"))
 startRemoteWorkerSystem();
 if (args.length == 0 || args[0].equals("Creation"))
 startRemoteCreationSystem();
 }
 
 public static void startRemoteWorkerSystem() {
 ActorSystem.create("CalculatorWorkerSystem",
 ConfigFactory.load(("calculator")));
 System.out.println("Started CalculatorWorkerSystem");
 }
 
 public static void startRemoteCreationSystem() {
 final ActorSystem system = ActorSystem.create("CreationSystem",
 ConfigFactory.load("remotecreation"));
 final ActorRef actor = system.actorOf(Props.create(CreationActor.class),
 "creationActor");
 
 System.out.println("Started CreationSystem");
 final Random r = new Random();
 system.scheduler().schedule(Duration.create(1, SECONDS),
 Duration.create(1, SECONDS), new Runnable() {
 @Override
 public void run() {
 if (r.nextInt(100) % 2 == 0) {
 actor.tell(new Op.Multiply(r.nextInt(100), r.nextInt(100)), null);
 } else {
 actor.tell(new Op.Divide(r.nextInt(10000), r.nextInt(99) + 1),
 null);
 }
 }
 }, system.dispatcher());
 }
 }

源码运行的结果为：

Started CalculatorWorkerSystem  
Started CreationSystem  
Calculating 4915.0 / 63  
Div result: 4915 / 63 = 78.02  
Calculating 1409.0 / 15  
Div result: 1409 / 15 = 93.93  
Calculating 99 \* 64  
Mul result: 99 \* 64 = 6336

# 4、源码分析 #

##  4.1，我们先看一下序列图，看看是如何调用的。 ##

![Center 3][]

## 4.2 一些关键内容的说明 ##

1、只能创建一个WorkerSystem

ActorSystem.create("CalculatorWorkerSystem",        ConfigFactory.load(("calculator")));

2、 只能创建一个ActorSystem

final ActorSystem system = ActorSystem.create("CreationSystem",    ConfigFactory.load("remotecreation"));

3、创建Actor

final ActorRef actor = system.actorOf(Props.create(CreationActor.class),   "creationActor");

4、发送消息给这个Actor

actor.tell(new Op.Multiply(r.nextInt(100), r.nextInt(100)), null);

5、 Actor 返回消息给上层调用的Actor

getSender().tell(result, getSelf());

[Center]: /images/20220715/1a3506eb590b46089769b4594797172c.png
[Center 1]: /images/20220715/54293198a4ba428891452bfd040f3135.png
[Center 2]: /images/20220715/f4ec0188204b4cacb30be3770b8a8079.png
[Center 3]: /images/20220715/0f9122f223734c9f999edbeed7393c69.png