Fanout——发布订阅模式,是一种广播机制。
此模式包括:一个生产者、一个交换机 (exchange)、多个队列、多个消费者。生产者将消息发送到交换机,交换机不存储消息,将消息存储到队列,消费者从队列中取消息。如果生产者将消息发送到没有绑定队列的交换机上,消息将丢失。
用 Java demo 实现此模式
package com.tszr.fanout; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import java.io.IOException; import java.util.concurrent.TimeoutException; public class Productor { private static final String EXCHANGE_NAME = "fanout_exchange"; public static void main(String[] args){ // 1、创建连接工程 ConnectionFactory factory = new ConnectionFactory(); factory.setHost("127.0.0.1"); factory.setUsername("guest"); factory.setPassword("guest"); factory.setVirtualHost("/"); Connection connection = null; Channel channel = null; try { // 2、获取连接、通道 connection = factory.newConnection(); channel = connection.createChannel(); // 消息内容 String message = "hello fanout mode"; // 指定路由key String routeKey = ""; String type = "fanout"; // 3、声明交换机 channel.exchangeDeclare(EXCHANGE_NAME, type); // 4、声明队列 channel.queueDeclare("queue1", false, false, false, null); channel.queueDeclare("queue2", false, false, false, null); channel.queueDeclare("queue3", false, false, false, null); channel.queueDeclare("queue4", false, false, false, null); // 5、绑定 channel 与 queue channel.queueBind("queue1", EXCHANGE_NAME, routeKey); channel.queueBind("queue2", EXCHANGE_NAME, routeKey); channel.queueBind("queue3", EXCHANGE_NAME, routeKey); channel.queueBind("queue4", EXCHANGE_NAME, routeKey); // 6、发布消息 channel.basicPublish(EXCHANGE_NAME, routeKey, null, message.getBytes("UTF-8")); System.out.println("消息发送成功!"); } catch (IOException | TimeoutException e) { e.printStackTrace(); System.out.println("消息发送异常"); }finally { // 关闭通道 if (channel != null && channel.isOpen()) { try { channel.close(); } catch (Exception e) { e.printStackTrace(); } } // 关闭连接 if (connection != null && connection.isOpen()) { try { connection.close(); } catch (Exception e) { e.printStackTrace(); } } } } }
package com.tszr.fanout; import com.rabbitmq.client.*; import java.io.IOException; import java.util.concurrent.TimeoutException; public class Customer { private static Runnable runnable = new Runnable() { @Override public void run() { // 创建连接工厂 ConnectionFactory factory = new ConnectionFactory(); factory.setHost("127.0.0.1"); factory.setUsername("guest"); factory.setPassword("guest"); factory.setVirtualHost("/"); final String queueName = Thread.currentThread().getName(); Connection connection = null; Channel channel = null; try { // 获取连接、通道 connection = factory.newConnection(); channel = connection.createChannel(); Channel finalChannel = channel; finalChannel.basicConsume(queueName, true, new DeliverCallback() { @Override public void handle(String consumerTag, Delivery delivery) throws IOException { System.out.println(delivery.getEnvelope().getDeliveryTag()); System.out.println(queueName + ":收到消息是:" + new String(delivery.getBody(), "UTF-8")); } }, new CancelCallback() { @Override public void handle(String consumerTag) throws IOException { } }); System.out.println(queueName + ":开始接收消息"); } catch (IOException | TimeoutException e) { e.printStackTrace(); } finally { // 关闭通道和连接...... } } }; public static void main(String[] args) throws IOException, TimeoutException { // 创建线程分别从四个队列中获取消息 new Thread(runnable, "queue1").start(); new Thread(runnable, "queue2").start(); new Thread(runnable, "queue3").start(); new Thread(runnable, "queue4").start(); } }