rabbitmq学习3:Publish/Subscribe

在前面的Work Queue中的消息是均匀分配消息给消费者；如果我想把消息分发给所有的消费者呢？那应当怎么操作呢？这就是要下面提到的Publish/Subscribe（分布/订阅）。让我们开始Publish/Subscribe之旅吧!

Publish/Subscribe的工作示意图如下：

在上图中的X表示Exchange(交换区);Exchange的类型有：direct , topic , headers 和 fanout

Publish/Subscribe的Exchang的类型为fanout;声明Publish/Subscribe的Exchang代码如下：

channel.exchangeDeclare("logs", "fanout");

 

对于Work Queue中提到的发布消息的代码如下：

channel.basicPublish("", queueName,   null, message.getBytes());

 但对于Publish/Subscribe中发布消息中的Queue的使用的是默认的；代码如下：

channel.basicPublish( "logs", "", null, message.getBytes());

 

Exchange和各Queue之间是如何通信的呢？主要是通过把Exchange和各Queue绑定（binding）；示意代码如下:

channel.queueBind(queueName, exchangeName, "");

Publish/Subscribe加入绑定的工作示意图如下：

 

那我们就开始程序代码吧：P端的代码如下：

 

package com.abin.rabbitmq;

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

public class EmitLog {
    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");//声明Exchange
        for (int i = 0; i <= 2; i++) {
            String message = "hello word!" + i;
            channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes());
            System.out.println(" [x] Sent '" + message + "'");
        }
        channel.close();
        connection.close();
    }

}

 运行结果如下：

[x] Sent 'hello word!0'
[x] Sent 'hello word!1'
[x] Sent 'hello word!2'

 

C端的代码如下：

package com.abin.rabbitmq;

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

public class ReceiveLogsOne {
    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = "log-fb1";
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, EXCHANGE_NAME, "");//把Queue、Exchange绑定
        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(queueName, true, consumer);
        while (true) {
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println(" [x] Received '" + message + "'");
        }
    }
}

 

对于C端的代码我写了二个差不多的程序，只需要修改一下queueName。这样就形成了二个Queue;运行结果相同；

运行结果可能如下：

[x] Received 'hello word!0'
[x] Received 'hello word!1'
[x] Received 'hello word!2'

 

 

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评论

1 楼 ZZX19880809 2014-11-01  

没看到有[x] Received 'hello word!0'输出