一、简述
延时消息在日常随处可见：
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。
最常用到方式为定时任务轮训，数据量小的时候使用没什么问题 而当有千万甚至上亿的数据量时就会出现数据读取的瓶颈，此时全表扫面进行处理一定是下下策。但是也有比较讨巧的方式，分享公司内部订单拆分的例子：
由于线上每天订单量50万+的增长量，单表早已无法吃撑这个增长的速度。采取的方式为订单归档：线上热数据保留2-3天的数据，其余都归档进入历史订单表中，这样热数据在200万以内。
订单超过10min不支付即取消的功能，可以采取简单的扫表形式而不会出现数据读取性能的问题。
这样的方式很简单，但需要跟业务进行沟通妥协，本文会讲另一种方式即RabbitMQ延迟队列。RabbitMQ实际并没有直接实现延时队列，但可利用RabbitMQ提供的属性来模拟延时队列，甚至已经有的配套的插件rabbitmq_delayed_message_exchange 下面先介绍使用到的RabbitMQ的属性。
1、消息的Time To Live (TTL)
x-message-ttl：消息过期时间，超过过期时间之后即变为死信（Dead-letter）不会再被消费者消费。
设置消息TTL有两种方式：
- 创建队列时指定x-message-ttl，此时队列所有的消息具有统一过期时间。
- 发送消息为每个消息设置 expiration，此时消息之间过期时间不同。
如果两者都设置，过期时间取两者最小。如果设置TTL为0即表示除非立马能发送到队列，否则直接丢弃该消息。利用TTL为0的特性再结合死信转发器可以替代RabbitMQ 3.0的immediate参数。
2、队列的TTL
x-expires: RabbitMQ会确保时间达到后将队列删除，但是并不保障这个动作有多及时。队列过期代表着处于未使用状态，即
- 队列无任何消费者
- 队列没有被重新声明
- 队列在过期未调用Basic.Get命令获取消息
3、x-dead-letter-exchange（RabbitMQ文档）：死信转发器（转发器类型）当消息达到过期时间未被消费则会由该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，如果未配置x-dead-letter-routing-key则会按照原队列的key进行转发。
4、队列的消息在以下几种情况会变成死信（Dead-letter）
- 设置的x-message-ttl或者expiration到期，即消息过期
- 消息被消费者拒绝(调用Basic.Reject / Basic.Nack)且 requeue参数设置为false
- 队列达到最大长度
二、示例demo
- 单个延迟队列
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
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>
DelayQueueTest.java
public class DelayQueueTest {
private ApplicationContext context = null;
@org.junit.Before
public void setUp() throws Exception {
context = new ClassPathXmlApplicationContext("rabbitmq/application.xml");
}
@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])
- 多个延迟队列
实际的业务需求中会出现不同的时间延迟，此时可设置多个队列以达到不同的延迟效果。例如5个队列 common-queue_5s、common-queue_15s、common-queue_30s、common-queue_45s、common-queue_50s达到不同的延迟效果，整体的结构如下：
上述bindingKey的值有所简化，但对路由结构图无影响。这里使用一个死信转发器（转发器类型）通过绑定不同的key路由到不同的死信队列。也可以死信转发器和死信队列一对一绑定 即 成对出现(dlx_exchange_5s 和 dead-letter-queue_5s)
这里贴出部分xml部分配置：
<?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"> <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" ignore-declaration-exceptions="true" /> <!-- 正常队列 -->
<!-- 5s过期 -->
<rabbit:queue name="common-queue_5s">
<rabbit:queue-arguments>
<entry key="x-message-ttl" value="5000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="dlx-exchange" />
<entry key="x-dead-letter-routing-key" value="dead-letter-queue_5s" />
</rabbit:queue-arguments>
</rabbit:queue>
<!-- 15s过期 -->
<rabbit:queue name="common-queue_15s">
<rabbit:queue-arguments>
<entry key="x-message-ttl" value="15000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="dlx-exchange" />
<entry key="x-dead-letter-routing-key" value="dead-letter-queue_15s" />
</rabbit:queue-arguments>
</rabbit:queue>
<!-- 30s过期 -->
<rabbit:queue name="common-queue_30s">
<rabbit:queue-arguments>
<entry key="x-message-ttl" value="30000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="dlx-exchange" />
<entry key="x-dead-letter-routing-key" value="dead-letter-queue_30s" />
</rabbit:queue-arguments>
</rabbit:queue>
<!-- 45s过期 -->
<rabbit:queue name="common-queue_45s">
<rabbit:queue-arguments>
<entry key="x-message-ttl" value="45000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="dlx-exchange" />
<entry key="x-dead-letter-routing-key" value="dead-letter-queue_45s" />
</rabbit:queue-arguments>
</rabbit:queue>
<!-- 50s过期 -->
<rabbit:queue name="common-queue_50s">
<rabbit:queue-arguments>
<entry key="x-message-ttl" value="50000" value-type="java.lang.Long" />
<entry key="x-dead-letter-exchange" value="dlx-exchange" />
<entry key="x-dead-letter-routing-key" value="dead-letter-queue_50s" />
</rabbit:queue-arguments>
</rabbit:queue>
<!-- 正常路由 -->
<rabbit:direct-exchange name="common-exchange" durable="false" id="common-exchange">
<rabbit:bindings>
<rabbit:binding queue="common-queue_5s" />
<rabbit:binding queue="common-queue_15s" />
<rabbit:binding queue="common-queue_30s" />
<rabbit:binding queue="common-queue_45s" />
<rabbit:binding queue="common-queue_50s" />
</rabbit:bindings>
</rabbit:direct-exchange> <!-- 死信队列 -->
<rabbit:queue name="dead-letter-queue_5s" />
<rabbit:queue name="dead-letter-queue_15s" />
<rabbit:queue name="dead-letter-queue_30s" />
<rabbit:queue name="dead-letter-queue_45s" />
<rabbit:queue name="dead-letter-queue_50s" />
<rabbit:direct-exchange name="dlx-exchange" durable="false" id="dlx-exchange">
<rabbit:bindings>
<rabbit:binding queue="dead-letter-queue_5s" />
<rabbit:binding queue="dead-letter-queue_15s" />
<rabbit:binding queue="dead-letter-queue_30s" />
<rabbit:binding queue="dead-letter-queue_45s" />
<rabbit:binding queue="dead-letter-queue_50s" />
</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="dead-letter-queue_5s" ref="receiveConfirmTestListener" />
<rabbit:listener queues="dead-letter-queue_15s" ref="receiveConfirmTestListener" />
<rabbit:listener queues="dead-letter-queue_30s" ref="receiveConfirmTestListener" />
<rabbit:listener queues="dead-letter-queue_45s" ref="receiveConfirmTestListener" />
<rabbit:listener queues="dead-letter-queue_50s" ref="receiveConfirmTestListener" />
</rabbit:listener-container></beans>
junit测试：
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:application-context.xml"})
public class TestDeadLetter {
@Autowired
private DeadLetterPublishService publishService; @Test
public void testALL() throws InterruptedException{
String message = "currentTime:" + System.currentTimeMillis();
System.out.println("test1---message: "+ message);
publishService.send("common-exchange","common-queue_5s", message);
publishService.send("common-exchange","common-queue_15s", message);
publishService.send("common-exchange","common-queue_30s", message);
publishService.send("common-exchange","common-queue_45s", message);
publishService.send("common-exchange","common-queue_50s", message);
Thread.sleep(100000);
}}
TestDeadLetter.java
最后运行结果：消息实际发送时间点 和 消息被延迟消费时间点无限接近 五个消息分别延迟大约 5s 15s 30s 45s 50s 但做不到精确一致。
test1---message: currentTime:
// 。。。。
- consumer--:MessageProperties [headers={spring_return_correlation=1ac8ee8e-6d61-4bbf-bac1-f21523a0d759, x-first-death-exchange=common-exchange, x-death=[{reason=expired, count=1, exchange=common-exchange, time=Tue Aug 27 23:34:18 CST 2019, routing-keys=[common-queue_5s], queue=common-queue_5s}], x-first-death-reason=expired, x-first-death-queue=common-queue_5s}, 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=dlx-exchange, receivedRoutingKey=dead-letter-queue_5s, deliveryTag=1, messageCount=0]:currentTime:1566920053524
1566920068578 - consumer--:MessageProperties [headers={spring_return_correlation=1ac8ee8e-6d61-4bbf-bac1-f21523a0d759, x-first-death-exchange=common-exchange, x-death=[{reason=expired, count=1, exchange=common-exchange, time=Tue Aug 27 23:34:28 CST 2019, routing-keys=[common-queue_15s], queue=common-queue_15s}], x-first-death-reason=expired, x-first-death-queue=common-queue_15s}, 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=dlx-exchange, receivedRoutingKey=dead-letter-queue_15s, deliveryTag=1, messageCount=0]:currentTime:1566920053524
1566920083550 - consumer--:MessageProperties [headers={spring_return_correlation=1ac8ee8e-6d61-4bbf-bac1-f21523a0d759, x-first-death-exchange=common-exchange, x-death=[{reason=expired, count=1, exchange=common-exchange, time=Tue Aug 27 23:34:43 CST 2019, routing-keys=[common-queue_30s], queue=common-queue_30s}], x-first-death-reason=expired, x-first-death-queue=common-queue_30s}, 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=dlx-exchange, receivedRoutingKey=dead-letter-queue_30s, deliveryTag=1, messageCount=0]:currentTime:1566920053524
1566920098549 - consumer--:MessageProperties [headers={spring_return_correlation=1ac8ee8e-6d61-4bbf-bac1-f21523a0d759, x-first-death-exchange=common-exchange, x-death=[{reason=expired, count=1, exchange=common-exchange, time=Tue Aug 27 23:34:58 CST 2019, routing-keys=[common-queue_45s], queue=common-queue_45s}], x-first-death-reason=expired, x-first-death-queue=common-queue_45s}, 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=dlx-exchange, receivedRoutingKey=dead-letter-queue_45s, deliveryTag=1, messageCount=0]:currentTime:1566920053524
1566920103551 - consumer--:MessageProperties [headers={spring_return_correlation=1ac8ee8e-6d61-4bbf-bac1-f21523a0d759, x-first-death-exchange=common-exchange, x-death=[{reason=expired, count=1, exchange=common-exchange, time=Tue Aug 27 23:35:03 CST 2019, routing-keys=[common-queue_50s], queue=common-queue_50s}], x-first-death-reason=expired, x-first-death-queue=common-queue_50s}, 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=dlx-exchange, receivedRoutingKey=dead-letter-queue_50s, deliveryTag=1, messageCount=0]:currentTime:1566920053524
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
