标签：read 交换机 tco 技术分享 try com trace rgs 简单
工作队列模式是直接在生产者与消费者里声明好一个队列，这种情况下消息只会对应同类型的消费者。
举个用户注册的列子：用户在注册完后一般都会发送消息通知用户注册成功（失败）。如果在一个系统中，用户注册信息有邮箱、手机号，那么在注册完后会向邮箱和手机号都发送注册完成信息。利用MQ实现业务异步处理，如果是用工作队列的话，就会声明一个注册信息队列。注册完成之后生产者会向队列提交一条注册数据，消费者取出数据同时向邮箱以及手机号发送两条消息。但是实际上邮箱和手机号信息发送实际上是不同的业务逻辑，不应该放在一块处理。这个时候就可以利用发布/订阅模式将消息发送到转换机（EXCHANGE），声明两个不同的队列（邮箱、手机），并绑定到交换机。这样生产者只需要发布一次消息，两个队列都会接收到消息发给对应的消费者。
1、什么是发布/订阅模式（Publish/Subscribe）
简单解释就是，可以将消息发送给不同类型的消费者。做到发布一次，消费多个。下图取自于官方网站（RabbitMQ）的发布/订阅模式的图例
P：消息的生产者
X：交换机
红色：队列
C1，C2：消息消费者
下面是利用用户注册解释的该模式。（先运行两个消费者，在运行生产者。如果没有提前将队列绑定到交换机，那么直接运行生产者的话，消息是不会发到任何队列里的）
2、生产者（Send）代码
public class Send { private final static String EXCHANGE_NAME = "test_exchange_fanout"; public static void main(String[] args) { try { //获取连接 Connection connection = ConnectionUtil.getConnection(); //从连接中获取一个通道 Channel channel = connection.createChannel(); //声明交换机（分发:发布/订阅模式） channel.exchangeDeclare(EXCHANGE_NAME, "fanout"); //发送消息 for (int i = 0; i < 10; i++) { String message = "this is user registe message" + i; System.out.println("[send]：" + message); //发送消息 channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("utf-8")); Thread.sleep(5 * i); } channel.close(); connection.close(); } catch (Exception e) { e.printStackTrace(); } } }
运行结果：
[send]：this is user registe message0
[send]：this is user registe message1
[send]：this is user registe message2
[send]：this is user registe message3
[send]：this is user registe message4
[send]：this is user registe message5
[send]：this is user registe message6
[send]：this is user registe message7
[send]：this is user registe message8
[send]：this is user registe message9
3、消费者1（ReceiveEmail）
public class ReceiveEmail { //交换机名称 private final static String EXCHANGE_NAME = "test_exchange_fanout"; //队列名称 private static final String QUEUE_NAME = "test_queue_email"; public static void main(String[] args) { try { //获取连接 Connection connection = ConnectionUtil.getConnection(); //从连接中获取一个通道 final Channel channel = connection.createChannel(); //声明交换机（分发:发布/订阅模式） channel.exchangeDeclare(EXCHANGE_NAME, "fanout"); //声明队列 channel.queueDeclare(QUEUE_NAME, false, false, false, null); //将队列绑定到交换机 channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ""); //保证一次只分发一个 int prefetchCount = 1; channel.basicQos(prefetchCount); //定义消费者 DefaultConsumer consumer = new DefaultConsumer(channel) { //当消息到达时执行回调方法 @Override public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException { String message = new String(body, "utf-8"); System.out.println("[email] Receive message：" + message); try { //消费者休息2s处理业务 Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } finally { System.out.println("[1] done"); //手动应答 channel.basicAck(envelope.getDeliveryTag(), false); } } }; //设置手动应答 boolean autoAck = false; //监听队列 channel.basicConsume(QUEUE_NAME, autoAck, consumer); } catch (IOException e) { e.printStackTrace(); } } }
运行结果：
[email] Receive message：this is user registe message0
[1] done
[email] Receive message：this is user registe message1
[1] done
[email] Receive message：this is user registe message2
[1] done
[email] Receive message：this is user registe message3
[1] done
[email] Receive message：this is user registe message4
[1] done
[email] Receive message：this is user registe message5
[1] done
[email] Receive message：this is user registe message6
[1] done
[email] Receive message：this is user registe message7
[1] done
[email] Receive message：this is user registe message8
[1] done
[email] Receive message：this is user registe message9
[1] done
4、消费者2（ReceivePhone）
public class ReceivePhone { //交换机名称 private final static String EXCHANGE_NAME = "test_exchange_fanout"; //队列名称 private static final String QUEUE_NAME = "test_queue_phone"; public static void main(String[] args) { try { //获取连接 Connection connection = ConnectionUtil.getConnection(); //从连接中获取一个通道 final Channel channel = connection.createChannel(); //声明交换机（分发:发布/订阅模式） channel.exchangeDeclare(EXCHANGE_NAME, "fanout"); //声明队列 channel.queueDeclare(QUEUE_NAME, false, false, false, null); //将队列绑定到交换机 channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ""); //保证一次只分发一个 int prefetchCount = 1; channel.basicQos(prefetchCount); //定义消费者 DefaultConsumer consumer = new DefaultConsumer(channel) { //当消息到达时执行回调方法 @Override public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException { String message = new String(body, "utf-8"); System.out.println("[phone] Receive message：" + message); try { //消费者休息2s处理业务 Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } finally { System.out.println("[2] done"); //手动应答 channel.basicAck(envelope.getDeliveryTag(), false); } } }; //设置手动应答 boolean autoAck = false; //监听队列 channel.basicConsume(QUEUE_NAME, autoAck, consumer); } catch (IOException e) { e.printStackTrace(); } } }
运行结果：
[phone] Receive message：this is user registe message0
[2] done
[phone] Receive message：this is user registe message1
[2] done
[phone] Receive message：this is user registe message2
[2] done
[phone] Receive message：this is user registe message3
[2] done
[phone] Receive message：this is user registe message4
[2] done
[phone] Receive message：this is user registe message5
[2] done
[phone] Receive message：this is user registe message6
[2] done
[phone] Receive message：this is user registe message7
[2] done
[phone] Receive message：this is user registe message8
[2] done
[phone] Receive message：this is user registe message9
[2] done
总结：
1、该模式下生产者并不是直接操作队列，而是将数据发送给交换机，由交换机将数据发送给与之绑定的队列。从运行结果中可以看到，两中类型的消费者（Email，Phone）都收到相同数量的消息。
2、该模式必须声明交换机，并且设置模式：channel.exchangeDeclare(EXCHANGE_NAME, "fanout") fanout指分发模式（将每一条消息都发送到与交换机绑定的队列。
3、 队列必须绑定交换机：channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "");
注意：本文仅代表个人理解和看法哟！和本人所在公司和团体无任何关系！
RabbitMQ学习第三记：发布/订阅模式（Publish/Subscribe）
标签：read 交换机 tco 技术分享 try com trace rgs 简单
原文地址：https://www.cnblogs.com/wy697495/p/9614005.html
