rabbitmq-----发布订阅模式
模型组成
一个消费者Producer，一个交换机Exchange，多个消息队列Queue，多个消费者Consumer
一个生产者，多个消费者，每一个消费者都有自己的一个队列，生产者没有将消息直接发送到队列，而是发送到了交换机，每个队列绑定交换机，生产者发送的消息经过交换机，到达队列，实现一个消息被多个消费者获取的目的。需要注意的是，如果将消息发送到一个没有队列绑定的exchange上面，那么该消息将会丢失，这是因为在rabbitMQ中exchange不具备存储消息的能力，只有队列具备存储消息的能力。
Exchange
相比较于前两种模型Hello World和Work，这里多一个一个Exchange。其实Exchange是RabbitMQ的标配组成部件之一，前两种没有提到Exchange是为了简化模型，即使模型中没有看到Exchange的声明，其实还是声明了一个默认的Exchange。
RabbitMQ中实际发送消息并不是直接将消息发送给消息队列，消息队列也没那么聪明知道这条消息从哪来要到哪去。RabbitMQ会先将消息发送个Exchange，Exchange会根据这条消息打上的标记知道该条消息从哪来到哪去。
Exchange凭什么知道消息的何去何从，因为Exchange有几种类型：direct，fanout，topic和headers。这里说的订阅者模式就可以认为是fanout模式了。
RabbitMQ中，所有生产者提交的消息都由Exchange来接受，然后Exchange按照特定的策略转发到Queue进行存储
RabbitMQ提供了四种Exchange：fanout,direct,topic,header .发布/订阅模式就是是基于fanout Exchange实现的。 -
fanout这种模式不需要指定队列名称，需要将Exchange和queue绑定，他们之间的关系是‘多对多’的关系 任何发送到fanout Exchange的消息都会被转发到与该Exchange绑定的queue上面。
订阅者模式有何不同
订阅者模式相对前面的Work模式有和不同？Work也有多个消费者，但是只有一个消息队列，并且一个消息只会被某一个消费者消费。但是订阅者模式不一样，它有多个消息队列，也有多个消费者，而且一条消息可以被多个消费者消费，类似广播模式。下面通过实例代码看看这种模式是如何收发消息的。1 package com.maozw.mq.pubsub; 2 3 import com.maozw.mq.config.RabbitConfig; 4 import com.rabbitmq.client.Channel; 5 import org.slf4j.Logger; 6 import org.slf4j.LoggerFactory; 7 import org.springframework.amqp.rabbit.connection.Connection; 8 import org.springframework.amqp.rabbit.connection.ConnectionFactory; 9 import org.springframework.beans.factory.annotation.Autowired;10 import org.springframework.web.bind.annotation.PathVariable;11 import org.springframework.web.bind.annotation.RequestMapping;12 import org.springframework.web.bind.annotation.RestController;13 14 import java.io.IOException;15 import java.util.concurrent.TimeoutException;16 17 import static org.apache.log4j.varia.ExternallyRolledFileAppender.OK;18 19 /**20 * work 模式21 * 两种分发： 轮询分发 + 公平分发22 * 轮询分发：消费端：自动确认消息；boolean autoAck = true;23 * 公平分发: 消费端：手动确认消息 boolean autoAck = false; channel.basicAck(envelope.getDeliveryTag(),false);24 *25 * @author MAOZW26 * @Description: ${todo}27 * @date 2018/11/26 15:0628 */29 @RestController30 @RequestMapping("/publish")31 public class PublishProducer {32 private static final Logger LOGGER = LoggerFactory.getLogger(PublishProducer.class);33 @Autowired34 RabbitConfig rabbitConfig;35 36 37 @RequestMapping("/send/{exchangeName}/{queueName}")38 public String send(@PathVariable String exchangeName, @PathVariable String queueName) throws IOException, TimeoutException {39 Connection connection = null;40 Channel channel= null;41 try {42 ConnectionFactory connectionFactory = rabbitConfig.connectionFactory();43 connection = connectionFactory.createConnection();44 channel = connection.createChannel(false);45 46 /**47 * 申明交换机48 */49 channel.exchangeDeclare(exchangeName,"fanout");50 51 /**52 * 发送消息53 * 每个消费者 发送确认消息之前，消息队列不会发送下一个消息给消费者，一次只处理一个消息54 * 自动模式无需设置下面设置55 */56 int prefetchCount = 1;57 channel.basicQos(prefetchCount);58 59 String Hello = ">>>> Hello Simple <<<<";60 for (int i = 0; i < 5; i++) {61 String message = Hello + i;62 channel.basicPublish(RabbitConfig.EXCHANGE_AAAAA, "", null, message.getBytes());63 LOGGER.info("生产消息： " + message);64 }65 return "OK";66 }catch (Exception e) {67 68 } finally {69 connection.close();70 channel.close();71 return OK;72 }73 }74 }
订阅1
1 package com.maozw.mq.pubsub; 2 3 import com.maozw.mq.config.RabbitConfig; 4 import com.rabbitmq.client.AMQP; 5 import com.rabbitmq.client.Channel; 6 import com.rabbitmq.client.DefaultConsumer; 7 import com.rabbitmq.client.Envelope; 8 import org.slf4j.Logger; 9 import org.slf4j.LoggerFactory;10 import org.springframework.amqp.rabbit.connection.Connection;11 import org.springframework.amqp.rabbit.connection.ConnectionFactory;12 13 import java.io.IOException;14 15 /**16 * @author MAOZW17 * @Description: ${todo}18 * @date 2018/11/26 15:0619 */20 21 public class SubscribeConsumer {22 private static final Logger LOGGER = LoggerFactory.getLogger(SubscribeConsumer.class);23 24 public static void main(String[] args) throws IOException {25 ConnectionFactory connectionFactory = RabbitConfig.getConnectionFactory();26 Connection connection = connectionFactory.createConnection();27 Channel channel = connection.createChannel(false);28 /**29 * 创建队列申明30 */31 boolean durable = true;32 channel.queueDeclare(RabbitConfig.QUEUE_PUBSUB_FANOUT, durable, false, false, null);33 /**34 * 绑定队列到交换机35 */36 channel.queueBind(RabbitConfig.QUEUE_PUBSUB_FANOUT, RabbitConfig.EXCHANGE_AAAAA,"");37 38 /**39 * 改变分发规则40 */41 channel.basicQos(1);42 DefaultConsumer consumer = new DefaultConsumer(channel) {43 @Override44 public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {45 super.handleDelivery(consumerTag, envelope, properties, body);46 System.out.println("[2] 接口数据 ： " + new String(body, "utf-8"));47 try {48 Thread.sleep(300);49 } catch (InterruptedException e) {50 e.printStackTrace();51 } finally {52 System.out.println("[2] done!");53 //消息应答：手动回执，手动确认消息54 channel.basicAck(envelope.getDeliveryTag(),false);55 }56 }57 };58 //监听队列59 /**60 * autoAck 消息应答61 * 默认轮询分发打开：true ：这种模式一旦rabbitmq将消息发送给消费者，就会从内存中删除该消息，不关心客户端是否消费正常。62 * 使用公平分发需要关闭autoAck:false 需要手动发送回执63 */64 boolean autoAck = false;65 channel.basicConsume(RabbitConfig.QUEUE_PUBSUB_FANOUT,autoAck, consumer);66 }67 68 } 1 package com.maozw.mq.pubsub; 2 3 import com.maozw.mq.config.RabbitConfig; 4 import com.rabbitmq.client.AMQP; 5 import com.rabbitmq.client.Channel; 6 import com.rabbitmq.client.DefaultConsumer; 7 import com.rabbitmq.client.Envelope; 8 import org.slf4j.Logger; 9 import org.slf4j.LoggerFactory;10 import org.springframework.amqp.rabbit.connection.Connection;11 import org.springframework.amqp.rabbit.connection.ConnectionFactory;12 13 import java.io.IOException;14 15 /**16 * @author MAOZW17 * @Description: ${todo}18 * @date 2018/11/26 15:0619 */20 21 public class SubscribeConsumer2 {22 private static final Logger LOGGER = LoggerFactory.getLogger(SubscribeConsumer2.class);23 24 public static void main(String[] args) throws IOException {25 ConnectionFactory connectionFactory = RabbitConfig.getConnectionFactory();26 Connection connection = connectionFactory.createConnection();27 Channel channel = connection.createChannel(false);28 /**29 * 创建队列申明30 */31 boolean durable = true;32 channel.queueDeclare(RabbitConfig.QUEUE_PUBSUB_FANOUT2, durable, false, false, null);33 /**34 * 绑定队列到交换机35 */36 channel.queueBind(RabbitConfig.QUEUE_PUBSUB_FANOUT2, RabbitConfig.EXCHANGE_AAAAA,"");37 38 /**39 * 改变分发规则40 */41 channel.basicQos(1);42 DefaultConsumer consumer = new DefaultConsumer(channel) {43 @Override44 public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {45 super.handleDelivery(consumerTag, envelope, properties, body);46 System.out.println("[2] 接口数据 ： " + new String(body, "utf-8"));47 try {48 Thread.sleep(400);49 } catch (InterruptedException e) {50 e.printStackTrace();51 } finally {52 System.out.println("[2] done!");53 //消息应答：手动回执，手动确认消息54 channel.basicAck(envelope.getDeliveryTag(),false);55 }56 }57 };58 //监听队列59 /**60 * autoAck 消息应答61 * 默认轮询分发打开：true ：这种模式一旦rabbitmq将消息发送给消费者，就会从内存中删除该消息，不关心客户端是否消费正常。62 * 使用公平分发需要关闭autoAck:false 需要手动发送回执63 */64 boolean autoAck = false;65 channel.basicConsume(RabbitConfig.QUEUE_PUBSUB_FANOUT2,autoAck, consumer);66 }67 }