Apache Camel系列(4)----Akka Camel

Akka是一个高性能，高容错的的分布式框架，并且对Camel也提供了很好的支持，下面创建一个Akka Camel的demo，运行环境：CentOS7 + IntelliJ + JDK8。这个demo分别创建一个Producer和Consumer，实现Redis的pub/sub功能。

 

1，创建Maven工程，加入dependencies，pom.xml文件如下：

 

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-core</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-spring</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-spring-redis</artifactId>
            <version>2.17.0</version>
        </dependency>

        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-stream</artifactId>
            <version>2.17.0</version>
        </dependency>
        <dependency>
            <groupId>com.typesafe.akka</groupId>
            <artifactId>akka-actor_2.11</artifactId>
            <version>2.4.0</version>
        </dependency>
        <dependency>
            <groupId>com.typesafe.akka</groupId>
            <artifactId>akka-camel_2.11</artifactId>
            <version>2.4.0</version>
        </dependency>
    </dependencies>

2，分别创建MyRedisProducer和MyRedisConsumer类，这两个类分别继承akka提供的UntypedProducerActor和UntypedConsumerActor，用于产生和消费消息，代码如下：

 

 

/**
 * Created by sam on 5/9/16.
 */
public class MyRedisProducer extends UntypedProducerActor {

    public void preStart() {
        super.preStart();
    }

    @Override
    public String getEndpointUri() {
        return "spring-redis://localhost:9999?connectionFactory=#connectionFactory&serializer=#serializer";
    }

    @Override
    public void onRouteResponse(Object message) {
        System.out.println("response from route:{}" + message);
    }

    @Override
    public Object onTransformOutgoingMessage(Object message) {
        if (message instanceof CamelMessage) {
            CamelMessage camelMessage = (CamelMessage) message;
            return camelMessage;
        } else {
            Map<String, Object> headers = new HashMap<String, Object>();
            headers.put("CamelRedis.Command", "PUBLISH");
            headers.put("CamelRedis.Channel", "testChannel");
            headers.put("CamelRedis.Message", message.toString());
            CamelMessage camelMessage = new CamelMessage(message, headers);
            return camelMessage;
        }
    }
}

在MyRedisProducer类中，需要预处理收到的消息，为消息设置headers属性，Camel Redis组件是根据headers属性类执行命令的。

getEndpointUri中用到的connectionFactory和serializer，会在创建actor的时候进行定义。

 

/**
 * Created by sam on 5/9/16.
 */
public class MyRedisConsumer extends UntypedConsumerActor {

    @Override
    public String getEndpointUri() {
        return "spring-redis://localhost:9999?connectionFactory=#connectionFactory&serializer=#serializer&channels=testChannel&command=SUBSCRIBE";
    }

    @Override
    public void onReceive(Object o) throws Exception {
        System.out.println(o);
        if (o instanceof CamelMessage) {
            CamelMessage msg = (CamelMessage) o;
            System.out.println(msg.getBodyAs(String.class, getCamelContext()));
        }
    }
}

MyRedisConsumer会将接收到的消息放在message body中。

 

3，创建Actor，代码如下：

/**
 * Created by sam on 5/9/16.
 */
public class RedisTest {
    public static void main(String[] args) throws Exception {
        ActorSystem system = ActorSystem.create("redis-actor");
        Camel camel = CamelExtension.get(system); // 获取Camel对象，该对象可以直接操作Camel，比如获取CamelContext对象等。
        PropertyPlaceholderDelegateRegistry delegateRegistry = (PropertyPlaceholderDelegateRegistry) camel.context().getRegistry();
        JndiRegistry registry = (JndiRegistry) delegateRegistry.getRegistry(); // Apache Camel默认使用JndiRegistry来注册类信息。
        if (registry.lookup("connectionFactory") == null && registry.lookup("serializer") == null) {
            // 添加beans
            JedisConnectionFactory connectionFactory = new JedisConnectionFactory();
            connectionFactory.setHostName("localhost");
            connectionFactory.setPassword("1234567890");
            connectionFactory.setPort(9999);
            // call this method to initialize connection factory
            connectionFactory.afterPropertiesSet();
            registry.bind("connectionFactory", connectionFactory);

            registry.bind("serializer", new StringRedisSerializer());
        }

        // 创建producer和consumer
        ActorRef producer = system.actorOf(Props.create(MyRedisProducer.class), "redisProducer");
        ActorRef consumer = system.actorOf(Props.create(MyRedisConsumer.class), "redisConsumer");

        while (true) {
            Thread.sleep(1000);
            producer.tell(new Date().toString(), ActorRef.noSender());
        }
    }
}

在这段代码中，先获得默认的JndiRegistry对象，并注册connectionFactory和serializer beans，注意使用JndiRegistry时，需要在资源文件中添加jndi.properties文件，内容如下:

java.naming.factory.initial = org.apache.camel.util.jndi.CamelInitialContextFactory

最后使用producer来发送消息，在consumer中，会得到输出，结果如下：

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
response from route:{}CamelMessage(null, Map())
CamelMessage(Thu May 12 09:38:04 CST 2016, Map(MessageExchangeId -> ID-localhost-localdomain-33258-1463017082575-0-2, breadcrumbId -> ID-localhost-localdomain-33258-1463017082575-0-1, CamelRedis.Channel -> testChannel, CamelRedis.Pattern -> [B@5910162e))
Thu May 12 09:38:04 CST 2016
response from route:{}CamelMessage(null, Map())
CamelMessage(Thu May 12 09:38:05 CST 2016, Map(MessageExchangeId -> ID-localhost-localdomain-33258-1463017082575-0-4, breadcrumbId -> ID-localhost-localdomain-33258-1463017082575-0-3, CamelRedis.Channel -> testChannel, CamelRedis.Pattern -> [B@4154c5ce))
Thu May 12 09:38:05 CST 2016
response from route:{}CamelMessage(null, Map())
CamelMessage(Thu May 12 09:38:06 CST 2016, Map(MessageExchangeId -> ID-localhost-localdomain-33258-1463017082575-0-6, breadcrumbId -> ID-localhost-localdomain-33258-1463017082575-0-5, CamelRedis.Channel -> testChannel, CamelRedis.Pattern -> [B@2cb03be0))
Thu May 12 09:38:06 CST 2016