延時消息在日常隨處可見：
1、訂單創建10min之后不發起支付，自動取消。
2、30min定時推送一次郵件信息。
最常用到方式為定時任務輪訓，數據量小的時候使用沒什么問題 而當有千萬甚至上億的數據量時就會出現數據讀取的瓶頸，此時全表掃面進行處理一定是下下策。但是也有比較討巧的方式，分享公司內部訂單拆分的例子：
由於線上每天訂單量50萬+的增長量，單表早已無法吃撐這個增長的速度。采取的方式為訂單歸檔：線上熱數據保留2-3天的數據，其余都歸檔進入歷史訂單表中，這樣熱數據在200萬以內。
訂單超過10min不支付即取消的功能，可以采取簡單的掃表形式而不會出現數據讀取性能的問題。
這樣的方式很簡單，但需要跟業務進行溝通妥協，本文會講另一種方式即RabbitMQ延遲隊列。RabbitMQ實際並沒有直接實現延時隊列，但可利用RabbitMQ提供的屬性來模擬延時隊列，甚至已經有的配套的插件rabbitmq_delayed_message_exchange 下面先介紹使用到的RabbitMQ的屬性。
1、消息的Time To Live (TTL)
x-message-ttl：消息過期時間，超過過期時間之后即變為死信（Dead-letter）不會再被消費者消費。
設置消息TTL有兩種方式：
- 創建隊列時指定x-message-ttl，此時隊列所有的消息具有統一過期時間。
- 發送消息為每個消息設置 expiration，此時消息之間過期時間不同。
如果兩者都設置，過期時間取兩者最小。如果設置TTL為0即表示除非立馬能發送到隊列，否則直接丟棄該消息。利用TTL為0的特性再結合死信轉發器可以替代RabbitMQ 3.0的immediate參數。
2、隊列的TTL
x-expires: RabbitMQ會確保時間達到后將隊列刪除，但是並不保障這個動作有多及時。隊列過期代表着處於未使用狀態，即
- 隊列無任何消費者
- 隊列沒有被重新聲明
- 隊列在過期未調用Basic.Get命令獲取消息
3、x-dead-letter-exchange（RabbitMQ文檔）：死信轉發器（轉發器類型）當消息達到過期時間未被消費則會由該exchange按照配置的x-dead-letter-routing-key轉發到指定隊列，最后被消費者消費，如果未配置x-dead-letter-routing-key則會按照原隊列的key進行轉發。
4、隊列的消息在以下幾種情況會變成死信（Dead-letter）
- 設置的x-message-ttl或者expiration到期，即消息過期
- 消息被消費者拒絕(調用Basic.Reject / Basic.Nack)且 requeue參數設置為false
- 隊列達到最大長度
RabbitMQ延時隊列邏輯：
1、exchange_delay_begin：緩沖隊列exchange交換器，用於將消息轉發至緩存消息隊列 queue_delay_begin 。
2、exchange_delay_done：死信（dead-letter）隊列exchange交換器，用於將隊列 queue_delay_begin 轉發到死信隊列。
3、queue_delay_begin：緩沖消息隊列，等待消息過期。
4、queue_delay_done：死信消息隊列，消費者能夠真正消費信息。
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，指定連接rabbit server參數 --> <rabbit:connection-factory id="connectionFactory" username="guest" password="guest" host="127.0.0.1" port="5672" publisher-confirms="true"/> <!-- 延時隊列 --> <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> <!-- 隊列過期時間 --> <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 相同為 【delay】exchange轉發消息到多個隊列 --> <!--<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" /> <!-- 掃描指定package注釋的注冊為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); } }
運行結果： 發送消息 10s之后， 消費監聽到消息 消費。
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])
實際的業務需求中會出現不同的時間延遲，此時可設置多個隊列以達到不同的延遲效果。例如5個隊列 common-queue_5s、common-queue_15s、common-queue_30s、common-queue_45s、common-queue_50s達到不同的延遲效果，整體的結構如下：
上述bindingKey的值有所簡化，但對路由結構圖無影響。這里使用一個死信轉發器（轉發器類型）通過綁定不同的key路由到不同的死信隊列。也可以死信轉發器和死信隊列一對一綁定 即 成對出現(dlx_exchange_5s 和 dead-letter-queue_5s)
這里貼出部分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" /> <!-- 正常隊列 --> <!-- 5s過期 --> <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過期 --> <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過期 --> <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過期 --> <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過期 --> <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> <!-- 死信隊列 --> <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, 監聽的類和queue的對應關系 --> <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測試：
@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); } }
最后運行結果：消息實際發送時間點 和 消息被延遲消費時間點無限接近 五個消息分別延遲大約 5s 15s 30s 45s 50s 但做不到精確一致。
test1---message: currentTime:1566920053524 // 。。。。 1566920058551 - 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
參考資料：
DLX： https://www.rabbitmq.com/dlx.html
RabbitMQ如何實現延遲隊列？：https://blog.csdn.net/u013256816/article/details/55106401
消息隊列之 RabbitMQ ：https://www.jianshu.com/p/79ca08116d57
使用RabbitMQ實現延遲任務 : https://www.cnblogs.com/haoxinyue/p/6613706.html