RabbitMQ之主题模糊匹配

Posted 2021-02-09 zengnansheng

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

通过匹配交换器，我们可以配置更灵活的消息系统

 

匹配交换器的匹配符

*（星号）表示一个单词

#（井号）表示零个或者多个单词

 

这次的例子中，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

 

三个关键字来绑定，消费者C1绑定关键字是【*.orange.*】,消费者C2绑定关键字是【*.*.rabbit】和【lazy.#】

消费者C1会收到所有orange这种颜色相关的消息

消费者C2会收到所有rabbit这个动物相关的消息和所有速度lazy的动物的消息

 

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。

 

生产者

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class Producer {
    private static final String EXCHANGE_NAME = "myexchange";
    // 路由关键字
    private static final 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" };

    public static void main(String[] argv) throws Exception {
        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");
            // 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("p Sent ‘" + severity + "‘:‘" + message + "‘");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (Exception ignore) {
                }
            }
        }
    }
}

 

 

消费者1

import java.io.IOException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class Consumer1 {
    // 交换器名称
    private static final String EXCHANGE_NAME = "myexchange";
    // 路由关键字
    private static final String[] routingKeys = new String[] { "*.orange.*" };

    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();

        // 绑定路由关键字
        for (String bindingKey : routingKeys) {
            channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);
            System.out.println("ReceiveTopic1 exchange:" + EXCHANGE_NAME + ", queue:" + queueName
                    + ", BindRoutingKey:" + bindingKey);
        }
        System.out.println("Consumer1 Waiting for messages...");
        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("Consumer1 Received ‘" + envelope.getRoutingKey() + "‘:‘" + message + "‘");
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
}

 

消费者2

import java.io.IOException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class Consumer2 {
    // 交换器名称
    private static final String EXCHANGE_NAME = "myexchange";
    // 路由关键字
    private static final String[] routingKeys = new String[]{"*.*.rabbit", "lazy.#"};

    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();

        // 绑定路由关键字
        for (String bindingKey : routingKeys) {
            channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);
            System.out.println("ReceiveTopic2 exchange:" + EXCHANGE_NAME + ", queue:" + queueName + ", BindRoutingKey:"
                    + bindingKey);
        }
        System.out.println("Consumer2 Waiting for messages...");
        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("Consumer2 Received ‘" + envelope.getRoutingKey() + "‘:‘" + message + "‘");
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
}

 

 

 

生产者发送“quick.orange.rabbit”的消息，两个消费者都会收到。

生产者发送“lazy.orange.elephant”，两个消费者都会收到。

生产者发送"quick.orange.fox"，那么只有C1能收到。

生产者发送"lazy.brown.fox"，那么只有C2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C2的【lazy.#】规则匹配上，发送到C2中。