消息延时在日常随处可见：
1、订单创建10min之后不发起支付，自动取消。
2、30min定时推送一次邮件信息。
最常用到方式后台定时任务轮训，量小的时候可以使用，量大会出现数据读取会性能问题。RabbitMQ并没有直接实现延时队列，但是可以利用RabbitMQ两个属性实现延时队列特性：
1、x-message-ttl：消息过期时间（Time To Live，TTL），超过过期时间之后即变为死信（Dead-letter），不会再被消费者消费。
设置TTL有两种方式：
（1）创建队列时指定x-message-ttl，此时整个队列具有统一过期时间；
（2）发送消息为每个消息设置expiration，此时消息之间过期时间不同。
注意：如果两者都设置，过期时间取两者最小。
2、x-dead-letter-exchange（RabbitMQ文档） ：过期消息路由转发（转发器类型），当消息达到过期时间由该exchange按照配置的x-dead-letter-routing-key转发到指定队列，最后被消费者消费。
spring整合RabbitMQ ：
RabbitMQ延时队列逻辑：
1、exchange_delay_begin：缓冲队列exchange交换器，用于将消息转发至缓存消息队列 queue_delay_begin 。
2、exchange_delay_done：死信（dead-letter）队列exchange交换器，用于将队列 queue_delay_begin 转发到死信队列。
3、queue_delay_begin：缓冲消息队列，等待消息过期。
4、queue_delay_done：死信消息队列，消费者能够真正消费信息。
spring-rabbitmq.xml ：
<?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:tx="http://www.springframework.org/schema/tx"
xmlns:util="http://www.springframework.org/schema/util" xmlns:context="http://www.springframework.org/schema/context"
xmlns:rabbit="http://www.springframework.org/schema/rabbit"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
http://www.springframework.org/schema/rabbit http://www.springframework.org/schema/rabbit/spring-rabbit-1.6.xsd">
<!--配置connection-factory，指定连接rabbit server参数 -->
<rabbit:connection-factory id="connectionFactory" username="guest" password="guest" host="127.0.0.1" port="5672" publisher-confirms="true"/>
<!-- 延时队列 -->
<rabbit:direct-exchange id="exchange_delay_begin" name="exchange_delay_begin" durable="false" auto-delete="false" >
<rabbit:bindings>
<rabbit:binding queue="queue_delay_begin" key="delay" />
</rabbit:bindings>
</rabbit:direct-exchange>
<rabbit:queue name="queue_delay_begin" durable="false">
<rabbit:queue-arguments>
<!-- 队列过期时间 -->
<entry key="x-message-ttl" value="30000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="exchange_delay_done" />
<entry key="x-dead-letter-routing-key" value="delay" />
</rabbit:queue-arguments>
</rabbit:queue>
<rabbit:direct-exchange id="exchange_delay_done" name="exchange_delay_done" durable="false" auto-delete="false" >
<rabbit:bindings>
<rabbit:binding queue="queue_delay_done" key="delay" />
<!-- binding key 相同为 【delay】exchange转发消息到多个队列 -->
<!--<rabbit:binding queue="queue_delay_done_two" key="delay" />-->
</rabbit:bindings>
</rabbit:direct-exchange>
<rabbit:queue name="queue_delay_done" durable="false"/>
<rabbit:template id="delayMsgTwoTemplate" connection-factory="connectionFactory" />
<bean id="messageConsumer" class="com.nancy.rabbitmq.demo.MessageConsumer"></bean>
<!-- 消息接收者 -->
<rabbit:listener-container connection-factory="connectionFactory" channel-transacted="false" >
<rabbit:listener queues="queue_delay_done" ref="messageConsumer" />
</rabbit:listener-container>
</beans>
DelayMessageProducer.java
@Service
public class DelayMessageProducer {
@Resource(name="delayMsgTwoTemplate")
private AmqpTemplate delayMsgTwoTemplate;
public void delayMsgTwo(String exchange, String routingKey, Object msg) {
delayMsgTwoTemplate.convertAndSend(exchange, routingKey, msg, new MessagePostProcessor() {
@Override
public Message postProcessMessage(Message message) throws AmqpException {
message.getMessageProperties().setExpiration(String.valueOf(10000));
return message;
}
});
}
}
MessageConsumer.java
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageListener;
public class MessageConsumer implements MessageListener {
@Override
public void onMessage(Message message) {
System.out.println("consumer receive message 22------->:{}"+ message);
}
}
application.xml
<?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:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<import resource="spring-rabbitmq.xml" />
<!-- 扫描指定package注释的注册为Spring Beans -->
<context:component-scan base-package="com.nancy.rabbitmq" />
<!-- 激活annotation功能 -->
<context:annotation-config />
<!-- 激活annotation功能 -->
<context:spring-configured />
</beans>
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>learning-demo</artifactId>
<groupId>com.nancy</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>demo-jms</artifactId>
<packaging>jar</packaging>
<name>demo-jms</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>5.0.0.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>1.8.6</version>
</dependency>
<!--依赖包 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jms</artifactId>
<version>${spring.version}</version>
</dependency>
<!--rabbit MQ -->
<dependency>
<groupId>org.springframework.amqp</groupId>
<artifactId>spring-amqp</artifactId>
<version>1.6.6.RELEASE</version>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.amqp</groupId>
<artifactId>spring-rabbit</artifactId>
<version>1.6.6.RELEASE</version>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
</exclusion>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
</exclusion>
</exclusions>
</dependency>
<!--spring -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>${spring.version}</version>
<exclusions>
<exclusion>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
<!--junit -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
</dependencies>
</project>
DelayQueueTest.java
import com.alibaba.fastjson.JSONObject;
import com.nancy.rabbitmq.delay.DelayMessageProducer;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class DelayQueueTest {
private ApplicationContext context = null;
// @Ignore
@org.junit.Before
public void setUp() throws Exception {
context = new ClassPathXmlApplicationContext("rabbitmq/application.xml");
}
// @Ignore
@Test
public void delayQueueTest() throws Exception {
DelayMessageProducer messageProducer = context.getBean(DelayMessageProducer.class);
int a = 10;
while (a > 0) {
System.out.println("send "+ a);
messageProducer.delayMsgTwo("exchange_delay_begin","delay", "hello world delay2 :" + a--);
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
System.out.println("sended ");
Thread.sleep(1000*60);
}
}
运行结果： 发送消息 10s之后， 消费监听到消息 消费。
send 10
send 9
send 8
send 7
send 6
send 5
send 4
send 3
send 2
send 1
sended
consumer receive message 22------->:{}(Body:‘hello world delay2 :10‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=1, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :9‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=2, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :8‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=3, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :7‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=4, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :6‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=5, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :5‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=6, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :4‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=7, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :3‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=8, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :2‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=9, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
consumer receive message 22------->:{}(Body:‘hello world delay2 :1‘ MessageProperties [headers={x-first-death-exchange=exchange_delay_begin, x-death=[{reason=expired, original-expiration=10000, count=1, exchange=exchange_delay_begin, time=Sun Jul 01 18:33:19 CST 2018, routing-keys=[delay], queue=queue_delay_begin}], x-first-death-reason=expired, x-first-death-queue=queue_delay_begin}, timestamp=null, messageId=null, userId=null, receivedUserId=null, appId=null, clusterId=null, type=null, correlationId=null, correlationIdString=null, replyTo=null, contentType=text/plain, contentEncoding=UTF-8, contentLength=0, deliveryMode=null, receivedDeliveryMode=PERSISTENT, expiration=null, priority=0, redelivered=false, receivedExchange=exchange_delay_done, receivedRoutingKey=delay, receivedDelay=1000, deliveryTag=10, messageCount=0, consumerTag=amq.ctag-oOJzeYHEJYrLFL4HbHWZcA, consumerQueue=queue_delay_done])
参考资料：
DLX： https://www.rabbitmq.com/dlx.html
RabbitMQ如何实现延迟队列？：https://blog.csdn.net/u013256816/article/details/55106401
消息队列之 RabbitMQ ：https://www.jianshu.com/p/79ca08116d57
使用RabbitMQ实现延迟任务 : https://www.cnblogs.com/haoxinyue/p/6613706.html
转自：https://www.cnblogs.com/xiaoxing/p/9250823.html
原文：https://www.cnblogs.com/xkzhangsanx/p/11025944.html