RabbitMQ 四 消息确认 发送确认 接收确认

               

前面几篇记录了收发消息的demo,今天记录下关于 消息确认方面的 问题.

下面是几个问题:

1.为什么要进行消息确认?

2.rabbitmq消息确认 机制是什么样的?

3.发送方如何确认消息发送成功?什么样才算发送成功?

4.消费方如何告知rabbitmq消息消费成功或失败?

5.使用spring的代码示例

1.为什么要进行消息确认?

经常会听到丢消息的字眼, 对于前面的demo来说,就存在丢消息的隐患.

发送者没法确认是否发送成功,消费者处理失败也无法反馈.

没有消息确认机制,就会出现消息莫名其妙的没了,也不知道什么情况.

2.rabbitmq消息确认 机制是什么样的?

首先看官网对消息确认的介绍http://www.rabbitmq.com/confirms.html

网上会有很多总结的博客(包括现在看的),很多就是对官网的翻译.所以看资料首先要去官网看看,这很关键.

看上图官网的介绍.唯一保证消息不丢失的是使用事务,但是性能太差,作为补偿,有了消息确认机制.

并说明了开启方法,以及和事务模式不共存.

还写了一个例子,但是点进去那个链接已经失效了,新版的源码上也没有这个例子,我找了最近一版是3.6.7上面还有.

点这里看官方的例子

3.发送的消息什么样才算成功或失败? 如何确认?

判断消息成功或失败,其实就是看进行消息确认的时机,因为成功或失败后就会把结果告诉发送方.还是看官方解释:

意思如下:

确认消息不能路由时(exchange确认不能路由到任何queue),进行确认操作(确认失败).如果发送方设置了mandatory模式,则会先调用basic.return方法.

消息可以路由时,当需要发送的队列都发送成功后,进行消息确认.对于持久化的队列,意味着已经写入磁盘,对于镜像队列,意味着所有镜像都接受成功.

至于如何确认的问题,上面已经写了 basic.ack方法

4.消费方如何告知rabbitmq消息消费成功或失败?

如图可知,根据消费方不同的确认模式,确认时机也不同.

自动确认会在消息发送给消费者后立即确认,如果手动则当消费者调用ack,nack,reject几种方法时进行确认.

一般会设置手动模式,业务失败后可以进行一些操作.

5.使用spring的代码示例

下面是一个使用spring整合的代码示例:

首先是rabbitmq的配置文件:

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rabbit="http://www.springframework.org/schema/rabbit" xsi:schemaLocation="http://www.springframework.org/schema/beans     http://www.springframework.org/schema/beans/spring-beans.xsd    http://www.springframework.org/schema/rabbit    http://www.springframework.org/schema/rabbit/spring-rabbit-1.4.xsd">    <!-- spring-rabbit.xsd的版本要注意,很1.4以前很多功能都没有,要用跟jar包匹配的版本 -->     <bean id="jsonMessageConverter" class="org.springframework.amqp.support.converter.Jackson2JsonMessageConverter" /> <rabbit:connection-factory   id="connectionFactory"  host="${rabbit.host}"   port="${rabbit.port}"   username="${rabbit.username}"   password="${rabbit.password}"  publisher-confirms="true"  /> <rabbit:admin connection-factory="connectionFactory" /> <!-- 给模板指定转换器 --><!-- mandatory必须设置true,return callback才生效 --> <rabbit:template id="amqpTemplate" connection-factory="connectionFactory"   confirm-callback="confirmCallBackListener"  return-callback="returnCallBackListener"   mandatory="true"  />  <rabbit:queue name="CONFIRM_TEST" />   <rabbit:direct-exchange name="DIRECT_EX" id="DIRECT_EX" >  <rabbit:bindings>   <rabbit:binding queue="CONFIRM_TEST" />  </rabbit:bindings> </rabbit:direct-exchange> <!-- 配置consumer, 监听的类和queue的对应关系 --> <rabbit:listener-container  connection-factory="connectionFactory" acknowledge="manual" >  <rabbit:listener queues="CONFIRM_TEST" ref="receiveConfirmTestListener" /> </rabbit:listener-container></beans>

然后发送方:

import org.springframework.amqp.core.AmqpTemplate;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Service("publishService")public class PublishService {    @Autowired      private AmqpTemplate amqpTemplate;         public void send(String exchange, String routingKey, Object message) {       amqpTemplate.convertAndSend(exchange, routingKey, message);    }  }

消费方:

import org.springframework.amqp.core.Message;import org.springframework.amqp.rabbit.core.ChannelAwareMessageListener;import org.springframework.stereotype.Service;import com.rabbitmq.client.Channel;@Service("receiveConfirmTestListener")public class ReceiveConfirmTestListener implements ChannelAwareMessageListener {   @Override public void onMessage(Message message, Channel channel) throws Exception {  try{   System.out.println("consumer--:"+message.getMessageProperties()+":"+new String(message.getBody()));   channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);  }catch(Exception e){   e.printStackTrace();//TODO 业务处理   channel.basicNack(message.getMessageProperties().getDeliveryTag(), false,false);  } }  }  

确认后回调:

import org.springframework.amqp.rabbit.core.RabbitTemplate.ConfirmCallback;import org.springframework.amqp.rabbit.support.CorrelationData;import org.springframework.stereotype.Service;@Service("confirmCallBackListener")public class ConfirmCallBackListener implements ConfirmCallback{ @Override public void confirm(CorrelationData correlationData, boolean ack, String cause) {  System.out.println("confirm--:correlationData:"+correlationData+",ack:"+ack+",cause:"+cause); }}

失败后return回调:

import org.springframework.amqp.core.Message;import org.springframework.amqp.rabbit.core.RabbitTemplate.ReturnCallback;import org.springframework.stereotype.Service;@Service("returnCallBackListener")public class ReturnCallBackListener implements ReturnCallback{ @Override public void returnedMessage(Message message, int replyCode, String replyText, String exchange, String routingKey) {  System.out.println("return--message:"+new String(message.getBody())+",replyCode:"+replyCode+",replyText:"+replyText+",exchange:"+exchange+",routingKey:"+routingKey); }}

测试类:

import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;import com.dingcheng.confirms.publish.PublishService;    @RunWith(SpringJUnit4ClassRunner.class)  @ContextConfiguration(locations = {"classpath:application-context.xml"})  public class TestConfirm {      @Autowired      private PublishService publishService;          private static String exChange = "DIRECT_EX";          @Test      public void test1() throws InterruptedException{       String message = "currentTime:"+System.currentTimeMillis();     System.out.println("test1---message:"+message);     //exchange,queue 都正确,confirm被回调, ack=true     publishService.send(exChange,"CONFIRM_TEST",message);          Thread.sleep(1000);    }          @Test      public void test2() throws InterruptedException{       String message = "currentTime:"+System.currentTimeMillis();     System.out.println("test2---message:"+message);     //exchange 错误,queue 正确,confirm被回调, ack=false     publishService.send(exChange+"NO","CONFIRM_TEST",message);          Thread.sleep(1000);    }          @Test      public void test3() throws InterruptedException{       String message = "currentTime:"+System.currentTimeMillis();     System.out.println("test3---message:"+message);     //exchange 正确,queue 错误 ,confirm被回调, ack=true; return被回调 replyText:NO_ROUTE     publishService.send(exChange,"",message);  //        Thread.sleep(1000);    }          @Test      public void test4() throws InterruptedException{       String message = "currentTime:"+System.currentTimeMillis();     System.out.println("test4---message:"+message);     //exchange 错误,queue 错误,confirm被回调, ack=false     publishService.send(exChange+"NO","CONFIRM_TEST",message);          Thread.sleep(1000);    }  }  

测试结果:

test1---message:currentTime:1483786948506test2---message:currentTime:1483786948532consumer--:MessageProperties [headers={spring_return_correlation=445bc7ca-a5bd-47e2-8ba3-f0448420e441}, timestamp=null, messageId=null, userId=null, appId=null, clusterId=null, type=null, correlationId=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=DIRECT_EX, receivedRoutingKey=CONFIRM_TEST, deliveryTag=1, messageCount=0]:currentTime:1483786948506test3---message:currentTime:1483786948536confirm--:correlationData:null,ack:false,cause:channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)confirm--:correlationData:null,ack:false,cause:Channel closed by application[ERROR] 2017-01-07 19:02:28 org.springframework.amqp.rabbit.connection.CachingConnectionFactory.shutdownCompleted(CachingConnectionFactory.java:281):--> Channel shutdown: channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)   return--message:currentTime:1483786948536,replyCode:312,replyText:NO_ROUTE,exchange:DIRECT_EX,routingKey:confirm--:correlationData:null,ack:true,cause:nulltest4---message:currentTime:1483786948546confirm--:correlationData:null,ack:false,cause:channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)[ERROR] 2017-01-07 19:02:28 org.springframework.amqp.rabbit.connection.CachingConnectionFactory.shutdownCompleted(CachingConnectionFactory.java:281):--> Channel shutdown: channel error; protocol method: #method<channel.close>(reply-code=404, reply-text=NOT_FOUND - no exchange 'DIRECT_EXNO' in vhost '/', class-id=60, method-id=40)   

代码和配置里面,已经都有注释,就不在多说明了.(callback是异步的,所以测试中sleep1秒钟等待下)

总结下就是:

如果消息没有到exchange,则confirm回调,ack=false

如果消息到达exchange,则confirm回调,ack=true

exchange到queue成功,则不回调return

exchange到queue失败,则回调return(需设置mandatory=true,否则不回回调,消息就丢了)

备注:需要说明,spring-rabbit和原生的rabbit-client ,表现是不一样的.

测试的时候,原生的client,exchange错误的话,直接就报错了,是不会到confirmListener和returnListener的

源码地址:https://github.com/qq315737546/spring-rabbit