RabbitMQ-死信交换机和死信队列-编程知识

RabbitMQ-死信交换机和死信队列

1. 简介

DLX: Dead-Letter-Exchange 死信交换器，死信邮箱

2.代码示例

@Configuration
public class RabbitConfig {final static String exchangeNormalName = "exchange.dlx.normal";final static String queueNormalName = "queue.dlx.normal";final static String exchangeDeadName = "exchange.dlx.dead";final static String queueDeadName = "queue.dlx.dead";//正常交换机@Beanpublic DirectExchange normalExchange(){return ExchangeBuilder.directExchange(exchangeNormalName).build();}//正常队列@Beanpublic Queue normalQueue(){Map<String, Object> map = new HashMap<>();map.put("x-message-ttl", 20000);//设置20s的过期时间map.put("x-dead-letter-exchange", exchangeDeadName);//设置死信交换机名字map.put("x-dead-letter-routing-key", "error");//设置死信交换机路由kreturn QueueBuilder.durable(queueNormalName).withArguments(map).build();}@Beanpublic Binding normalBinding(DirectExchange normalExchange, Queue normalQueue){return BindingBuilder.bind(normalQueue).to(normalExchange).with("order");}//死信交换机@Beanpublic DirectExchange dlxExchange(){return ExchangeBuilder.directExchange(exchangeDeadName).build();}//死信队列@Beanpublic Queue dlxQueue(){return QueueBuilder.durable(queueDeadName).build();}@Beanpublic Binding dlxBinding(DirectExchange dlxExchange, Queue dlxQueue){return BindingBuilder.bind(dlxQueue).to(dlxExchange).with("error");}}

如上，设置普通交换机把过期内容放置到死信交换机中去。最重要的几行代码

		map.put("x-message-ttl", 20000);//设置20s的过期时间map.put("x-dead-letter-exchange", exchangeDeadName);//设置死信交换机名字map.put("x-dead-letter-routing-key", "error");//设置死信交换机路由k

3.测试结果

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经过20s之后，如下，将普通队列的信息放入死信队列中

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其中TTL代表x-message-ttl，DLX代表x-dead-letter-exchange，DLK代表x-dead-letter-routing-key

4.单条消息

上方是将整个队列设置过期时间，也可以将单条消息设置过期时间，即不给整个队列设置过期时间

		//map.put("x-message-ttl", 20000);//设置20s的过期时间map.put("x-dead-letter-exchange", exchangeDeadName);//设置死信交换机名字map.put("x-dead-letter-routing-key", "error");//设置死信交换机路由k

而是在消息体中设置过期时间

@Component
@Slf4j
public class MessageService {@Autowiredprivate RabbitTemplate rabbitTemplate;public void senMsg() throws InterruptedException {//定义消息String msg="单条消息过期时间test";MessageProperties messageProperties = new MessageProperties();messageProperties.setExpiration("10000"); //10sMessage message= MessageBuilder.withBody(msg.getBytes()).andProperties(messageProperties).build();//发消息rabbitTemplate.convertAndSend("exchange.dlx.normal","order",message);log.info("消息发送完毕，发送时间为:{}", new Date());}
}