RabbitMQ入门教程 For Java【5】 - Topic
操作系统: Windows7 64bit
开发环境: JDK 1.7 - 1.7.0_55
开发工具: Eclipse Kepler SR2
RabbitMQ版本: 3.6.0
Elang版本: erl7.2.1
关于Windows7下安装RabbitMQ的教程请先在网上找一下,有空我再补安装教程。
https://github.com/chwshuang/rabbitmq.git
匹配模式,如果按照百度翻译和百度百科,直接叫主题或者话题就得了,但是如果你真的明白它在RabbitMQ中代表什么,就不能这么直接的翻译成中文了。如果要用中文理解它的意思,先了解它在RabbitMQ中用来做什么:topic类型的交换器允许在RabbitMQ中使用模糊匹配来绑定自己感兴趣的信息。
所以,我觉得这一章应该叫macth模式更合适,中文 - 匹配模式。
在上一章,通过直连交换器,生产者发送不同路由关键字的日志,消费者端通过绑定自己感兴趣的路由关键字来接收消息,进行完善日志系统。如果我想只接收生产者com.test.rabbitmq.topic包下的日志,其他包的忽略掉,之前的日志系统处理起来可能就非常麻烦,还好,我们有匹配模式,现在我们将生产者发送过来的消息按照包名来命名,那么消费者端就可以在匹配模式下使用【#.topic.*】这个路由关键字来获得感兴趣的消息。
通过匹配交换器,我们可以配置更灵活的消息系统,你可以在匹配交换器模式下发送这样的路由关键字:
“a.b.c”、“c.d”、“quick.orange.rabbit”
不过一定要记住,路由关键字【routingKey】不能超过255个字节(bytes)
匹配交换器的匹配符
这一章的例子中,我们使用三个段式的路由关键字,有三个单词和两个点组成。第一个词是速度,第二个词是颜色,第三个是动物名称。
我们用三个关键字来绑定,Q1绑定关键字是【*.orange.*】,Q2绑定关键字是【*.*.rabbit】和【lazy.#】,然后分析会发生什么:
生产者发送“quick.orange.rabbit”的消息,两个队列都会收到
生产者发送“lazy.orange.elephant”,两队列也都会收到。
生产者发送"quick.orange.fox",那么只有Q1会收到。
生产者发送"lazy.brown.fox",那么只会有Q2能收到。
生产者发送"quick.brown.fox",那么这条消息会被丢弃,谁也收不到。
生产者发送"quick.orange.male.rabbit",这个消息也会被丢弃,谁也收不到。
生产者发送"lazy.orange.male.rabbit",这个消息会被Q2的【lazy.#】规则匹配上,发送到Q2队列中。
交换器在匹配模式下:
如果消费者端的路由关键字只使用【#】来匹配消息,在匹配【topic】模式下,它会变成一个分发【fanout】模式,接收所有消息。
如果消费者端的路由关键字中没有【#】或者【*】,它就变成直连【direct】模式来工作。
ReceiveLogsTopic1.java
import com.rabbitmq.client.*; import java.io.IOException; public class ReceiveLogsTopic1 { private static final String EXCHANGE_NAME = "topic_logs"; public static void main(String[] argv) throws Exception { ConnectionFactory factory = new ConnectionFactory(); factory.setHost("localhost"); Connection connection = factory.newConnection(); Channel channel = connection.createChannel(); // 声明一个匹配模式的交换器 channel.exchangeDeclare(EXCHANGE_NAME, "topic"); String queueName = channel.queueDeclare().getQueue(); // 路由关键字 String[] routingKeys = new String[]{"*.orange.*"}; // 绑定路由关键字 for (String bindingKey : routingKeys) { channel.queueBind(queueName, EXCHANGE_NAME, bindingKey); System.out.println("ReceiveLogsTopic1 exchange:"+EXCHANGE_NAME+", queue:"+queueName+", BindRoutingKey:" + bindingKey); } System.out.println("ReceiveLogsTopic1 [*] Waiting for messages. To exit press CTRL+C"); Consumer consumer = new DefaultConsumer(channel) { @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException { String message = new String(body, "UTF-8"); System.out.println("ReceiveLogsTopic1 [x] Received '" + envelope.getRoutingKey() + "':'" + message + "'"); } }; channel.basicConsume(queueName, true, consumer); } }
import com.rabbitmq.client.*; import java.io.IOException; public class ReceiveLogsTopic2 { private static final String EXCHANGE_NAME = "topic_logs"; public static void main(String[] argv) throws Exception { ConnectionFactory factory = new ConnectionFactory(); factory.setHost("localhost"); Connection connection = factory.newConnection(); Channel channel = connection.createChannel(); // 声明一个匹配模式的交换器 channel.exchangeDeclare(EXCHANGE_NAME, "topic"); String queueName = channel.queueDeclare().getQueue(); // 路由关键字 String[] routingKeys = new String[]{"*.*.rabbit", "lazy.#"}; // 绑定路由关键字 for (String bindingKey : routingKeys) { channel.queueBind(queueName, EXCHANGE_NAME, bindingKey); System.out.println("ReceiveLogsTopic2 exchange:"+EXCHANGE_NAME+", queue:"+queueName+", BindRoutingKey:" + bindingKey); } System.out.println("ReceiveLogsTopic2 [*] Waiting for messages. To exit press CTRL+C"); Consumer consumer = new DefaultConsumer(channel) { @Override public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException { String message = new String(body, "UTF-8"); System.out.println("ReceiveLogsTopic2 [x] Received '" + envelope.getRoutingKey() + "':'" + message + "'"); } }; channel.basicConsume(queueName, true, consumer); } }
import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.Connection; import com.rabbitmq.client.Channel; public class TopicSend { private static final String EXCHANGE_NAME = "topic_logs"; public static void main(String[] argv) { Connection connection = null; Channel channel = null; try { ConnectionFactory factory = new ConnectionFactory(); factory.setHost("localhost"); connection = factory.newConnection(); channel = connection.createChannel(); // 声明一个匹配模式的交换器 channel.exchangeDeclare(EXCHANGE_NAME, "topic"); // 待发送的消息 String[] routingKeys = new String[]{"quick.orange.rabbit", "lazy.orange.elephant", "quick.orange.fox", "lazy.brown.fox", "quick.brown.fox", "quick.orange.male.rabbit", "lazy.orange.male.rabbit"}; // 发送消息 for(String severity :routingKeys){ String message = "From "+severity+" routingKey' s message!"; channel.basicPublish(EXCHANGE_NAME, severity, null, message.getBytes()); System.out.println("TopicSend [x] Sent '" + severity + "':'" + message + "'"); } } catch (Exception e) { e.printStackTrace(); } finally { if (connection != null) { try { connection.close(); } catch (Exception ignore) { } } } } }
ReceiveLogsTopic1 [*] Waiting for messages. To exit press CTRL+C
再运行ReceiveLogsTopic2
ReceiveLogsTopic2 exchange:topic_logs, queue:amq.gen-JwqUJNUGpdFGkeY5B6TsLw, BindRoutingKey:*.*.rabbit ReceiveLogsTopic2 exchange:topic_logs, queue:amq.gen-JwqUJNUGpdFGkeY5B6TsLw, BindRoutingKey:lazy.# ReceiveLogsTopic2 [*] Waiting for messages. To exit press CTRL+C
TopicSend [x] Sent 'quick.orange.rabbit':'From quick.orange.rabbit routingKey' s message!' TopicSend [x] Sent 'lazy.orange.elephant':'From lazy.orange.elephant routingKey' s message!' TopicSend [x] Sent 'quick.orange.fox':'From quick.orange.fox routingKey' s message!' TopicSend [x] Sent 'lazy.brown.fox':'From lazy.brown.fox routingKey' s message!' TopicSend [x] Sent 'quick.brown.fox':'From quick.brown.fox routingKey' s message!' TopicSend [x] Sent 'quick.orange.male.rabbit':'From quick.orange.male.rabbit routingKey' s message!' TopicSend [x] Sent 'lazy.orange.male.rabbit':'From lazy.orange.male.rabbit routingKey' s message!'
ReceiveLogsTopic1 [x] Received 'quick.orange.rabbit':'From quick.orange.rabbit routingKey' s message!' ReceiveLogsTopic1 [x] Received 'lazy.orange.elephant':'From lazy.orange.elephant routingKey' s message!' ReceiveLogsTopic1 [x] Received 'quick.orange.fox':'From quick.orange.fox routingKey' s message!'
ReceiveLogsTopic2 [x] Received 'quick.orange.rabbit':'From quick.orange.rabbit routingKey' s message!' ReceiveLogsTopic2 [x] Received 'lazy.orange.elephant':'From lazy.orange.elephant routingKey' s message!' ReceiveLogsTopic2 [x] Received 'lazy.brown.fox':'From lazy.brown.fox routingKey' s message!' ReceiveLogsTopic2 [x] Received 'lazy.orange.male.rabbit':'From lazy.orange.male.rabbit routingKey' s message!'
最后,咱们来开动脑筋看看下面的题,当是我留的课外作业:
如果你的课外作业做完,并且自己动手验证过,OK,进入第六章-远程方法调用吧!
本教程所有文章:
RabbitMQ入门教程 For Java【1】 - Hello World - 你好世界!
RabbitMQ入门教程 For Java【2】 - Work Queues - 工作队列
RabbitMQ入门教程 For Java【3】 - Publish/Subscribe - 发布/订阅
RabbitMQ入门教程 For Java【4】 - Routing - 消息路由
RabbitMQ入门教程 For Java【5】 - Topic - 模糊匹配
RabbitMQ入门教程 For Java【6】 - Remote procedure call (RPC) - 远程调用
由于本教程中rabbitmq是在本机安装,使用的是默认端口(5672)。
如果你的例子运行中的主机、端口不同,请进行必要设置,否则可能无法运行。
如果你阅读这个教程有障碍,可以通过GitHub项目成员找到开发者的邮件地址联系他们。
https://github.com/orgs/rabbitmq/people