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.liuwenwu.rabbitmqaqi.confirm; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.QueueingConsumer; public class Consumer { public static void main(String[] args) throws Exception { //1 创建ConnectionFactory ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); //2 获取C onnection Connection connection = connectionFactory.newConnection(); //3 通过Connection创建一个新的Channel Channel 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Key channel.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.liuwenwu.rabbitmqaqi.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; public class Producer { public static void main(String[] args) throws Exception { //1 创建ConnectionFactory ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); connectionFactory.setPort(5672); connectionFactory.setVirtualHost("/"); //2 获取C onnection Connection connection = connectionFactory.newConnection(); //3 通过Connection创建一个新的Channel Channel 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() { @Override public void handleNack(long deliveryTag, boolean multiple) throws IOException { System.err.println("-------no ack!-----------"); } @Override public 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.liuwenwu.rabbitmqaqi.returnlistener; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; import com.rabbitmq.client.QueueingConsumer; public class Consumer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); 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.liuwenwu.rabbitmqaqi.returnlistener; import com.rabbitmq.client.*; import java.io.IOException; public class Producer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); 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() { @Override public 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ReturnListener channel.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.liuwenwu.rabbitmqaqi.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; public class MyConsumer extends DefaultConsumer { public MyConsumer(Channel channel) { super(channel); } @Override public 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.liuwenwu.rabbitmqaqi.consumer; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; public class Consumer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); 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.liuwenwu.rabbitmqaqi.consumer; import com.rabbitmq.client.Channel; import com.rabbitmq.client.Connection; import com.rabbitmq.client.ConnectionFactory; public class Producer { public static void main(String[] args) throws Exception { ConnectionFactory connectionFactory = new ConnectionFactory(); connectionFactory.setHost("192.168.241.134"); 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()); } } }