RabbitMQ+消息模式1
文章目录
- 消息100%的投递
- 幂等性概念
- Confirm确认消息
- Return返回消息
- 自定义消费者
消息100%的投递
消息如何保障100%的投递成功？
什么是生产端的可靠性投递？
保障消息的成功发出
保障MQ节点的成功接收
发送端收到MQ节点（Broker）确认应答
完善的消息进行补偿机制
BAT/TMD互联网大厂的解决方案：
消息落库，对消息状态进行打标
消息的延迟投递，做二次确认，回调检查
幂等性概念
幂等性是什么？
我们可以借鉴数据库的乐观锁机制
比如我们执行一条更新库存的SQL语句
Update t_repository set count = count -1,version = version + 1 where version = 1
Elasticsearch也是严格遵循幂等性概念，每次数据更新，version+1（博主博客前面有提到）
消费端-幂等性保障
在海量订单产生的业务高峰期，如何避免消息的重复消费问题？
消费实现幂等性，就意味着，我们的消息永远不会消费多次，即使我们收到了多条一样的消息
业界主流的幂等性操作
唯一ID+指纹码机制，利用数据库主键去重
利用Redis的原子性去实现
唯一ID+指纹码 机制
唯一ID+指纹码机制，利用数据库主键去重
Select count(1) from T_order where ID=唯一ID+指纹码
好处：实现简单
坏处：高并发下有数据库写入的性能瓶颈
解决方案：根据ID进行分库分表进行算法路由
利用Redis的原子性去实现
使用Redis进行幂等，需要考虑的问题
第一：我们是否要进行数据落库，如果落库的话，关键解决的问题是数据库和缓存如何做到原子性？
第二：如果不进行落库，那么都存储到缓存中，如何设置定时同步策略？
Confirm确认消息
理解Confirm消息确认机制
消息的确认，是指生产者投递消息后，如果Broker收到消息，则会给我们生产者 一个应答。
生产者进行接收应答，用来确定这条消息是否正常的发送到Broker，这种方式也是消息的可靠性投递的核心保障
如何实现Confirm确认消息？
第一步：在Channel上开启确认模式：channel.confirmSelect()
第二步：在channel上添加监听：addConfirmListener，监听成功和失败的返回结果，根据具体的结果对消息进行重新发送、或记录日志等后续处理！
消费端代码
package com.caoluo.rabbitmqapi.confirm;import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:12*/
public class Consumer {public static void main(String[] args) throws Exception {//1 创建ConnectionFactoryConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");//2 获取C onnectionConnection connection = connectionFactory.newConnection();//3 通过Connection创建一个新的ChannelChannel channel = connection.createChannel();String exchangeName = "test_confirm_exchange";String routingKey = "confirm.#";String queueName = "test_confirm_queue";//4 声明交换机和队列 然后进行绑定设置, 最后制定路由Keychannel.exchangeDeclare(exchangeName, "topic", true);channel.queueDeclare(queueName, true, false, false, null);channel.queueBind(queueName, exchangeName, routingKey);//5 创建消费者QueueingConsumer queueingConsumer = new QueueingConsumer(channel);channel.basicConsume(queueName, true, queueingConsumer);while(true){QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();String msg = new String(delivery.getBody());System.err.println("消费端: " + msg);}}
}服务提供方代码
package com.caoluo.rabbitmqapi.confirm;import com.rabbitmq.client.Channel;
import com.rabbitmq.client.ConfirmListener;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;import java.io.IOException;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:02*/
public class Producer {public static void main(String[] args) throws Exception {//1 创建ConnectionFactoryConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");//2 获取C onnectionConnection connection = connectionFactory.newConnection();//3 通过Connection创建一个新的ChannelChannel channel = connection.createChannel();//4 指定我们的消息投递模式: 消息的确认模式channel.confirmSelect();String exchangeName = "test_confirm_exchange";String routingKey = "confirm.save";//5 发送一条消息String msg = "Hello RabbitMQ Send confirm message!";channel.basicPublish(exchangeName, routingKey, null, msg.getBytes());//6 添加一个确认监听channel.addConfirmListener(new ConfirmListener() {@Overridepublic void handleNack(long deliveryTag, boolean multiple) throws IOException {System.err.println("-------no ack!-----------");}@Overridepublic void handleAck(long deliveryTag, boolean multiple) throws IOException {System.err.println("-------ack!-----------");}});}
}Return返回消息
Return Listener用于处理一些不可路由的消息！
正常情况：我们的消息生产者，通过指定一个Exchange和RoutingKey，把消息送达到某一个队列中去，然后我们的消费者监听队列，进行消费处理操作！
异常情况：在某些情况下，如果我们在发送消息的时候，当前的Exchange不存在或者指定的路由key路由不到，这个时候如果我们需要监听这种不可达的消息，就需要使用Return Listener！
在基础API中有一个关键的配置项
Mandatory：如果为true，则监听器会接收到路由不可达的消息，然后进行后续处理，如果为false，那么Broker端自动删除该消息！
消费端代码
package com.caoluo.rabbitmqapi.returnlistener;import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:02*/
public class Consumer {public static void main(String[] args) throws Exception {ConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");Connection connection = connectionFactory.newConnection();Channel channel = connection.createChannel();String exchangeName = "test_return_exchange";String routingKey = "return.#";String queueName = "test_return_queue";channel.exchangeDeclare(exchangeName, "topic", true, false, null);channel.queueDeclare(queueName, true, false, false, null);channel.queueBind(queueName, exchangeName, routingKey);QueueingConsumer queueingConsumer = new QueueingConsumer(channel);channel.basicConsume(queueName, true, queueingConsumer);while(true){QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();String msg = new String(delivery.getBody());System.err.println("消费者: " + msg);}}
}生产端代码
package com.caoluo.rabbitmqapi.returnlistener;import com.rabbitmq.client.*;import java.io.IOException;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:32*/
public class Producer {public static void main(String[] args) throws Exception {ConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");Connection connection = connectionFactory.newConnection();Channel channel = connection.createChannel();String exchange = "test_return_exchange";String routingKey = "return.save";String routingKeyError = "abc.save";String msg = "Hello RabbitMQ Return Message";channel.addReturnListener(new ReturnListener() {@Overridepublic void handleReturn(int replyCode, String replyText, String exchange,String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {System.err.println("---------handle return----------");System.err.println("replyCode: " + replyCode);System.err.println("replyText: " + replyText);System.err.println("exchange: " + exchange);System.err.println("routingKey: " + routingKey);System.err.println("properties: " + properties);System.err.println("body: " + new String(body));}});//消息投递成功，会被消费者所消费
// channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());//消息不可达，将触发ReturnListenerchannel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());}
}自定义消费者
我们一般就是在代码中编写while循环，进行consumer.nextDelivery方法进行获取下一条消息，然后进行消费处理！
但是我们使用自定义的Consumer更加的方便，解耦性更加的强，也是实际工作中最常用的使用方式！
自定义消费端代码
package com.caoluo.rabbitmqapi.consumer;import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;import java.io.IOException;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:18*/
public class MyConsumer extends DefaultConsumer {public MyConsumer(Channel channel) {super(channel);}@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {System.err.println("-----------consume message----------");System.err.println("consumerTag: " + consumerTag);System.err.println("envelope: " + envelope);System.err.println("properties: " + properties);System.err.println("body: " + new String(body));}
}
消费端调用
package com.caoluo.rabbitmqapi.consumer;import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:15*/
public class Consumer {public static void main(String[] args) throws Exception {ConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");Connection connection = connectionFactory.newConnection();Channel channel = connection.createChannel();String exchangeName = "test_consumer_exchange";String routingKey = "consumer.#";String queueName = "test_consumer_queue";channel.exchangeDeclare(exchangeName, "topic", true, false, null);channel.queueDeclare(queueName, true, false, false, null);channel.queueBind(queueName, exchangeName, routingKey);channel.basicConsume(queueName, true, new MyConsumer(channel));}
}生产端调用
package com.caoluo.rabbitmqapi.consumer;import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;/*** @author caoluo* @site www.caoluo.com* @company* @create 2019-12-07 23:12*/
public class Producer {public static void main(String[] args) throws Exception {ConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost("192.168.147.146");connectionFactory.setPort(5672);connectionFactory.setVirtualHost("/");Connection connection = connectionFactory.newConnection();Channel channel = connection.createChannel();String exchange = "test_consumer_exchange";String routingKey = "consumer.save";String msg = "Hello RabbitMQ Consumer Message";for(int i =0; i<5; i ++){channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());}}
}
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