一、說明
在實際業務場景中可能會用到延時消息發送,例如異步回調失敗時的重發機制。 RabbitMQ本身不具有延時消息隊列的功能,但是可以通過rabbitmq-delayed-message-exchange來實現(也可以通過TTL(Time To Live)、DLX(Dead Letter Exchanges)特性實現,我們主要講解通過延遲插件來實現的方法)。利用RabbitMQ的這種特性,應該可以實現很多現實中的業務,我們可以發揮想象。
二、安裝插件
RabbitMQ的安裝請參考我的文章“RabbitMQ安裝與使用”,這里我們重點講插件的安裝。
首先到http://www.rabbitmq.com/community-plugins.html網頁下載適合的“rabbitmq_delayed_message_exchange插件”。下載完成后將它放到RabbitMQ插件安裝目錄({rabbitmq-server}/plugins/),然后執行命令rabbitmq-plugins enable rabbitmq_delayed_message_exchange啟用插件,執行命令rabbitmq-plugins disable rabbitmq_delayed_message_exchange也可以關閉插件。具體過程可以查看參考文檔2。
三、spring集成RabbitMQ
1、maven配置
- <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>
- <version>4.1.6.RELEASE</version>
- </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-core</artifactId>
- <version>4.1.6.RELEASE</version>
- </exclusion>
- <exclusion>
- <groupId>org.springframework</groupId>
- <artifactId>spring-messaging</artifactId>
- <version>4.1.6.RELEASE</version>
- </exclusion>
- <exclusion>
- <groupId>org.springframework</groupId>
- <artifactId>spring-tx</artifactId>
- <version>4.1.6.RELEASE</version>
- </exclusion>
- <exclusion>
- <groupId>org.springframework</groupId>
- <artifactId>spring-context</artifactId>
- <version>4.1.6.RELEASE</version>
- </exclusion>
- </exclusions>
- </dependency>
說明:實現延遲隊列需要Spring在4.1以上,spring-amqp在1.6以上。
2、xml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: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">
- <context:property-placeholder location="classpath:rmq-config.properties" ignore-unresolvable="true"/>
- <bean id="connectionFactory" class="org.springframework.amqp.rabbit.connection.CachingConnectionFactory">
- <property name="host" value="${rabbitmq.host}" />
- <property name="port" value="${rabbitmq.port}" />
- <property name="username" value="${rabbitmq.username}" />
- <property name="password" value="${rabbitmq.password}" />
- <property name="channelCacheSize" value="${rabbitmq.channel.cacheSize}" />
- </bean>
- <bean id="orderConsumer" class="com.xxx.rmq.OrderConsumer"></bean>
- <bean id="messageConverter" class="org.springframework.amqp.support.converter.SimpleMessageConverter" />
- <bean id="jsonMessageConverter" class="org.springframework.amqp.support.converter.Jackson2JsonMessageConverter" />
- <rabbit:admin connection-factory="connectionFactory" />
- <!-- 延遲消息start -->
- <rabbit:topic-exchange name="delay_exchange" delayed="true">
- <rabbit:bindings>
- <rabbit:binding queue="delay_queue" pattern="order.delay.notify" />
- </rabbit:bindings>
- </rabbit:topic-exchange>
- <rabbit:queue name="delay_queue" durable="true" auto-declare="true" auto-delete="false" />
- <rabbit:template id="delayMsgTemplate" connection-factory="connectionFactory" message-converter="jsonMessageConverter" exchange="delay_exchange" />
- <rabbit:listener-container connection-factory="connectionFactory" channel-transacted="false" acknowledge="auto" message-converter="jsonMessageConverter">
- <rabbit:listener queues="delay_queue" ref="orderConsumer" method="delayMsg" />
- </rabbit:listener-container>
- <!-- 延遲消息end -->
- </beans>
說明:spring-rabbit-1.6.xsd必須是1.6及以上版本,否則會報“元素 'rabbit:topic-exchange' 中不允許出現屬性 'delayed'”錯誤。具體請查看參考文檔3。
四、延遲隊列的使用
1、發送消息Producer
- import net.sf.json.JSONObject;
- import org.apache.commons.lang.StringUtils;
- import org.springframework.amqp.AmqpException;
- import org.springframework.amqp.core.AmqpTemplate;
- import org.springframework.amqp.core.Message;
- import org.springframework.amqp.core.MessagePostProcessor;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Service;
- /**
- *
- * @author Horace
- * @version 創建時間:2016年10月26日 下午6:34:31
- */
- @Service
- public class MessageProducerServiceImpl implements MessageProducerService{
- @Autowired
- private AmqpTemplate delayMsgTemplate;
- @Override
- public void delayMsg(JSONObject msg,int delay) {
- // TODO Auto-generated method stub
- final int xdelay= delay*1000;
- delayMsgTemplate.convertAndSend("order.delay.notify", (Object) msg,
- new MessagePostProcessor() {
- @Override
- public Message postProcessMessage(Message message)
- throws AmqpException {
- // TODO Auto-generated method stub
- message.getMessageProperties().setDelay(xdelay);
- return message;
- }
- });
- }
- }
2、異步接收消息Consumer
- import net.sf.json.JSONObject;
- import org.apache.commons.lang.StringUtils;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import org.springframework.beans.factory.annotation.Autowired;
- /**
- *
- * @author Horace
- * @version 創建時間:2016年10月26日 下午2:48:14
- */
- public class OrderConsumer {
- private static Logger logger = LoggerFactory.getLogger(OrderConsumer.class);
- @Autowired
- private MessageProducerService messageProducerService;
- public void delayMsg(Object obj) {
- logger.info("[延時消息]" + obj);
- if (obj != null) {
- JSONObject notifyJson = JSONObject.fromObject(obj);
- String notifyUrl = notifyJson.getString("notifyUrl");
- String notifyContent = notifyJson.getString("notifyContent");
- String result = HttpUtil.postMessage(notifyUrl, notifyContent);
- if (StringUtils.isBlank(result)) { // 通知失敗 進入重發機制
- int newNotifyCount = notifyJson.getInt("notifyCount") + 1; //已經通知的次數
- if (newNotifyCount < 5) {
- notifyJson.put("notifyCount", newNotifyCount);
- int spacingInterval = getSpacingInterval(newNotifyCount);
- messageProducerService
- .delayMsg(notifyJson, spacingInterval);
- } else {
- logger.info("通知5次都失敗,等待后台手工處理!");
- }
- }
- }
- }
- /**
- * 重復通知間隔時間(單位為秒)
- * @param notifyCount 已經通知的次數
- * @return
- */
- private int getSpacingInterval(int notifyCount) {
- // TODO Auto-generated method stub
- int spacingInterval = 0;
- switch (notifyCount) {
- case 1:
- spacingInterval = 10;
- break;
- case 2:
- spacingInterval = 20;
- break;
- case 3:
- spacingInterval = 30;
- break;
- case 4:
- spacingInterval = 60;
- break;
- case 5:
- spacingInterval = 90;
- break;
- default:
- break;
- }
- return spacingInterval;
- }
- }
