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:
Java代码
- channel.exchangeDeclare("logs", "fanout");
对于Work Queue中提到的发布消息的代码如下:
Java代码
- 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:
Java代码
- 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:
Java代码
- 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:
Java代码
- 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:
Java代码
- [x] Sent ‘hello word!0‘
- [x] Sent ‘hello word!1‘
- [x] Sent ‘hello word!2‘
C端的代码如下:
Java代码
- 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:
Java代码
- [x] Received ‘hello word!0‘
- [x] Received ‘hello word!1‘
- [x] Received ‘hello word!2‘
时间: 2024-10-10 02:31:10