Brief introduction
Delay queue stored message is not immediately get consumers want to be, but after waiting for a certain time, consumers can get this message consumption. More usage scenarios, such as limit orders for payment within 30 minutes, otherwise canceled, another example of a distributed environment, repeat the operation from time to time.
Here is an example of simple examples it is probably meaning 10 seconds after the first message transmission, after 40 seconds, 100 seconds to re-read the message. For illustrative, other unwanted characteristics RabbitMQ not used.
Ready to work
Installed in Centos7 RabbitMQ, stand-alone version is 3.6.12 version (non-clustered), IP is 127.0.0.1, port 15672, using the web management page or rabbitmqctl ready ahead of the relevant user, exchange and queue.
Users producer (with the user name password), consumer (user password the same name).
Default exchange RabbitMQ is predefined name is an empty string, automatically bind to each queue, type Direct, routingKey equal to the queue name.
Three badmail switch (the queue will be sent to message expiration in the dead letter queue exchanger) 10sDeadLetterExchange, 30sDeadLetterExchange, 60sDeadLetterExchange.
Three dead letter queue, 10sDeadLetterQueue, 30sDeadLetterQueue, 60sDeadLetterQueue are bound with three badmail exchanger.
Three queues, 10sDelayQueue, 30sDelayQueue, 60sDelayQueue, respectively set the expiration time of 10 seconds, 30 seconds, 60 seconds, and set the corresponding switch dead letter.
Examples
使用java代码创建一个生产者和三个消费者。生产者往Default exchange发送消息，
routingKey为10sDelayQueue。三个消费者分别订阅三个死信队列。先启动三个消费者，再启动生产者。消费者会持续订阅死信队列，需要手动关闭连接。
Rabbitmq10sDeadLetterQueueConsumer消费者代码如下：
import com.rabbitmq.client.*;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import java.util.concurrent.TimeoutException;
public class Rabbitmq10sDeadLetterQueueConsumer {
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setUsername("consumer");
connectionFactory.setPassword("consumer");
connectionFactory.setHost("127.0.0.1");
connectionFactory.setPort(15672);
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
channel.basicQos(64);
channel.basicConsume("10sDeadLetterQueue", false, UUID.randomUUID().toString(),
new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
System.out.println("第一次重试时间：" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
System.out.println("consumerTag:" + consumerTag);
System.out.println("envelope:" + envelope.toString());
System.out.println("basicProperties:" + properties.toString());
System.out.println("message:" + new String(body, "utf-8"));
channel.basicAck(envelope.getDeliveryTag(), false);
channel.basicPublish("", "30sDelayQueue",
new AMQP.BasicProperties().builder().deliveryMode(2).build(),
body);
}
});
}
}
Rabbitmq30sDeadLetterQueueConsumer消费者代码如下：
import com.rabbitmq.client.*;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import java.util.concurrent.TimeoutException;
public class Rabbitmq30sDeadLetterQueueConsumer {
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setUsername("consumer");
connectionFactory.setPassword("consumer");
connectionFactory.setHost("127.0.0.1");
connectionFactory.setPort(15672);
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
channel.basicQos(64);
channel.basicConsume("30sDeadLetterQueue", false, UUID.randomUUID().toString(),
new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
System.out.println("第二次重试时间：" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
System.out.println("consumerTag:" + consumerTag);
System.out.println("envelope:" + envelope.toString());
System.out.println("basicProperties:" + properties.toString());
System.out.println("message:" + new String(body, "utf-8"));
channel.basicAck(envelope.getDeliveryTag(), false);
channel.basicPublish("", "60sDelayQueue",
new AMQP.BasicProperties().builder().deliveryMode(2).build(),
body);
}
});
}
}
Rabbitmq60sDeadLetterQueueConsumer消费者代码如下：
import com.rabbitmq.client.*;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import java.util.concurrent.TimeoutException;
public class Rabbitmq60sDeadLetterQueueConsumer {
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setUsername("consumer");
connectionFactory.setPassword("consumer");
connectionFactory.setHost("127.0.0.1");
connectionFactory.setPort(15672);
Connection connection = connectionFactory.newConnection();
Channel channel = connection.createChannel();
channel.basicQos(64);
channel.basicConsume("60sDeadLetterQueue", false, UUID.randomUUID().toString(),
new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
System.out.println("第三次重试时间：" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
System.out.println("consumerTag:" + consumerTag);
System.out.println("envelope:" + envelope.toString());
System.out.println("basicProperties:" + properties.toString());
System.out.println("message:" + new String(body, "utf-8"));
channel.basicAck(envelope.getDeliveryTag(), false);
System.out.println("执行完成");
}
});
}
}
生产者代码如下：
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
import java.util.concurrent.TimeoutException;
public class RabbitmqDelayQueueProducer {
public static void main(String[] args) throws IOException, TimeoutException {
Connection connection = null;
Channel channel = null;
try {
ConnectionFactory connectionFactory = new ConnectionFactory();
connectionFactory.setVirtualHost("/");
connectionFactory.setUsername("producer");
connectionFactory.setPassword("producer");
connectionFactory.setHost("127.0.0.1");
connectionFactory.setPort(15672);
connection = connectionFactory.newConnection();
channel = connection.createChannel();
channel.basicPublish("", "10sDelayQueue",
new AMQP.BasicProperties().builder().deliveryMode(2).build(),
("测试延迟队列" + UUID.randomUUID().toString()).getBytes("utf-8"));
System.out.println("发送时间：" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
} finally {
if (channel != null) {
channel.close();
}
if (connection != null) {
connection.close();
}
}
}
}
生产者打印：
发送时间：2019-08-25 10:08:29
Rabbitmq10sDeadLetterQueueConsumer消费者打印：
第一次重试时间：2019-08-25 10:08:39
consumerTag:83787685-28a9-4ae8-b2bc-b89b90f14b68
envelope:Envelope(deliveryTag=1, redeliver=false, exchange=10sDeadLetterExchange, routingKey=10sDelayQueue)
basicProperties:#contentHeader<basic>(content-type=null, content-encoding=null, headers={x-death=[{reason=expired, count=1, exchange=, time=Sun Aug 25 10:08:37 CST 2019, routing-keys=[10sDelayQueue], queue=10sDelayQueue}]}, delivery-mode=2, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
message:测试延迟队列f862c616-a99a-4b65-9482-d74d5aee0814
Rabbitmq30sDeadLetterQueueConsumer消费者打印：
第二次重试时间：2019-08-25 10:09:09
consumerTag:27bb0e0e-07fe-49b6-8c0f-06fbc32cd784
envelope:Envelope(deliveryTag=1, redeliver=false, exchange=30sDeadLetterExchange, routingKey=30sDelayQueue)
basicProperties:#contentHeader<basic>(content-type=null, content-encoding=null, headers={x-death=[{reason=expired, count=1, exchange=, time=Sun Aug 25 10:09:07 CST 2019, routing-keys=[30sDelayQueue], queue=30sDelayQueue}]}, delivery-mode=2, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
message:测试延迟队列f862c616-a99a-4b65-9482-d74d5aee0814
Rabbitmq60sDeadLetterQueueConsumer消费者打印：
第三次重试时间：2019-08-25 10:10:09
consumerTag:8bfdc795-443d-4940-bf88-1e6f14e7b530
envelope:Envelope(deliveryTag=1, redeliver=false, exchange=60sDeadLetterExchange, routingKey=60sDelayQueue)
basicProperties:#contentHeader<basic>(content-type=null, content-encoding=null, headers={x-death=[{reason=expired, count=1, exchange=, time=Sun Aug 25 10:10:07 CST 2019, routing-keys=[60sDelayQueue], queue=60sDelayQueue}]}, delivery-mode=2, priority=null, correlation-id=null, reply-to=null, expiration=null, message-id=null, timestamp=null, type=null, user-id=null, app-id=null, cluster-id=null)
message:测试延迟队列f862c616-a99a-4b65-9482-d74d5aee0814
执行完成