RabbitMQ---订阅模型-Fanout

1、订阅模型-Fanout

Fanout，也称为广播。
流程图：
在这里插入图片描述

在广播模式下，消息发送流程是这样的：
1）可以有多个消费者
2）每个消费者有自己的queue（队列）
3）每个队列都要绑定到Exchange（交换机）
4）生产者发送的消息，只能发送到交换机，交换机来决定要发给哪个队列，生产者无法决定。
5）交换机把消息发送给绑定过的所有队列
6）队列的消费者都能拿到消息。实现一条消息被多个消费者消费

1.1、生产者

两个变化：
1）声明Exchange，不再声明Queue
2）发送消息到Exchange，不再发送到Queue

public class Send {private final static String EXCHANGE_NAME = "fanout_exchange_test";public static void main(String[] argv) throws Exception {// 获取到连接Connection connection = ConnectionUtil.getConnection();// 获取通道Channel channel = connection.createChannel();// 声明exchange，指定类型为fanoutchannel.exchangeDeclare(EXCHANGE_NAME, "fanout");// 消息内容String message = "Hello everyone";// 发布消息到Exchangechannel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes());System.out.println(" [生产者] Sent '" + message + "'");channel.close();connection.close();}
}

1.2、消费者1

public class Recv {private final static String QUEUE_NAME = "fanout_exchange_queue_1";private final static String EXCHANGE_NAME = "fanout_exchange_test";public static void main(String[] argv) throws Exception {// 获取到连接Connection connection = ConnectionUtil.getConnection();// 获取通道Channel channel = connection.createChannel();// 声明队列channel.queueDeclare(QUEUE_NAME, false, false, false, null);// 绑定队列到交换机channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "");// 定义队列的消费者DefaultConsumer consumer = new DefaultConsumer(channel) {// 获取消息，并且处理，这个方法类似事件监听，如果有消息的时候，会被自动调用@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body) throws IOException {// body 即消息体String msg = new String(body);System.out.println(" [消费者1] received : " + msg + "!");}};// 监听队列，自动返回完成channel.basicConsume(QUEUE_NAME, true, consumer);}
}

1.3、消费者2

public class Recv2 {private final static String QUEUE_NAME = "fanout_exchange_queue_2";private final static String EXCHANGE_NAME = "fanout_exchange_test";public static void main(String[] argv) throws Exception {// 获取到连接Connection connection = ConnectionUtil.getConnection();// 获取通道Channel channel = connection.createChannel();// 声明队列channel.queueDeclare(QUEUE_NAME, false, false, false, null);// 绑定队列到交换机channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "");// 定义队列的消费者DefaultConsumer consumer = new DefaultConsumer(channel) {// 获取消息，并且处理，这个方法类似事件监听，如果有消息的时候，会被自动调用@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties,byte[] body) throws IOException {// body 即消息体String msg = new String(body);System.out.println(" [消费者2] received : " + msg + "!");}};// 监听队列，手动返回完成channel.basicConsume(QUEUE_NAME, true, consumer);}
}