Time-To-Live and Expiration — RabbitMQ
一、死信队列
Dead Letter Exchanges — RabbitMQ
死信队列：
DLX 全称（Dead-Letter-Exchange）,称之为死信交换器，当消息变成一个死信之后，如果这个消息所在的队列存在x-dead-letter-exchange参数，那么它会被发送到x-dead-letter-exchange对应值的交换器上，这个交换器就称之为死信交换器，与这个死信交换器绑定的队列就是死信队列
死信消息：
- 消息被拒绝（Basic.Reject或Basic.Nack）并且设置 requeue 参数的值为 false
- 消息过期（消息TTL过期。TTL：Time To Live的简称，即过期时间）
- 队列达到最大的长度
过期消息：
在 rabbitmq 中存在2种方法可设置消息的过期时间:
- 第一种通过对队列进行设置，这种设置后，该队列中所有的消息都存在相同的过期时间
- 第二种通过对消息本身进行设置，那么每条消息的过期时间都不一样
如果同时使用这2种方法，那么以过期时间小的那个数值为准。当消息达到过期时间还没有被消费，那么那个消息就成为了一个 死信 消息
队列设置：在队列申明的时候使用** x-message-ttl **参数，单位为 毫秒；
- 队列中这个属性的设置要在第一次声明队列的时候设置才有效，如果队列一开始已存在且没有这个属性，则要删掉队列再重新声明才可以。
- 队列的 TTL 只能被设置为某个固定的值，一旦设置后则不能更改，否则会抛出异常
单个消息设置：是设置消息属性的 expiration 参数的值，单位为 毫秒。
说明：
对于第一种设置队列属性的方法，一旦消息过期，就会从队列中抹去；而在第二种方法中，即使消息过期，也不会马上从队列中抹去，因为每条消息是否过期是在即将投递到消费者之前判定的
1. 生产者：
声明队列的时候用属性指定其死信队列交换机名称。
测试：
package rabbitmq;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
public class Producer {
public static ConnectionFactory getConnectionFactory() {
// 创建连接工程，下面给出的是默认的case
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("192.168.99.100");
factory.setPort(5672);
factory.setUsername("guest");
factory.setPassword("guest");
factory.setVirtualHost("/");
return factory;
}
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = getConnectionFactory();
Connection newConnection = null;
Channel createChannel = null;
try {
newConnection = connectionFactory.newConnection();
createChannel = newConnection.createChannel();
// 声明一个正常的direct类型的交换机
createChannel.exchangeDeclare("order.exchange", BuiltinExchangeType.DIRECT);
// 声明死信交换机为===order.dead.exchange
String dlxName = "order.dead.exchange";
createChannel.exchangeDeclare(dlxName, BuiltinExchangeType.DIRECT);
// 声明队列并指定死信交换机为上面死信交换机
Map<String, Object> arg = new HashMap<String, Object>();
arg.put("x-dead-letter-exchange", dlxName);
createChannel.queueDeclare("myQueue", true, false, false, arg);
String message = "测试消息";
createChannel.basicPublish("order.exchange", "routing_key_myQueue", null, message.getBytes());
System.out.println("消息发送成功");
} catch (Exception e) {
e.printStackTrace();
} finally {
if (createChannel != null) {
createChannel.close();
}
if (newConnection != null) {
newConnection.close();
}
}
}
}结果：
(1)生成两个Exchange
(2)队列myQueue的死信队列有属性
2. 消费者：
一个消费者监听正常队列，一个消费者监听死信队列。(只是绑定的交换机不同)
消费者一：监听正常队列
package rabbitmq;
import java.io.IOException;
import java.util.Date;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.AMQP.BasicProperties;
public class Consumer {
public static ConnectionFactory getConnectionFactory() {
// 创建连接工程，下面给出的是默认的case
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("192.168.99.100");
factory.setPort(5672);
factory.setUsername("guest");
factory.setPassword("guest");
factory.setVirtualHost("/");
return factory;
}
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = getConnectionFactory();
Connection newConnection = null;
Channel createChannel = null;
try {
newConnection = connectionFactory.newConnection();
createChannel = newConnection.createChannel();
// 队列绑定交换机-channel.queueBind(队列名, 交换机名, 路由key[广播消息设置为空串])
createChannel.queueBind("myQueue", "order.exchange", "routing_key_myQueue");
createChannel.basicConsume("myQueue", false, "", new DefaultConsumer(createChannel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties,
byte[] body) throws IOException {
System.out.println("consumerTag: " + consumerTag);
System.out.println("envelope: " + envelope);
System.out.println("properties: " + properties);
String string = new String(body, "UTF-8");
System.out.println("接收到消息： -》 " + string);
long deliveryTag = envelope.getDeliveryTag();
Channel channel = this.getChannel();
System.out.println("拒绝消息， 使之进入死信队列");
System.out.println("时间： " + new Date());
try {
TimeUnit.SECONDS.sleep(3);
} catch (InterruptedException e) {
}
// basicReject第二个参数为false进入死信队列或丢弃
channel.basicReject(deliveryTag, false);
}
});
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
}消费者二：监听死信队列
package rabbitmq;
import java.io.IOException;
import java.util.Date;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.AMQP.BasicProperties;
public class Consumer2 {
public static ConnectionFactory getConnectionFactory() {
// 创建连接工程，下面给出的是默认的case
ConnectionFactory factory = new ConnectionFactory();
factory.setHost("192.168.99.100");
factory.setPort(5672);
factory.setUsername("guest");
factory.setPassword("guest");
factory.setVirtualHost("/");
return factory;
}
public static void main(String[] args) throws IOException, TimeoutException {
ConnectionFactory connectionFactory = getConnectionFactory();
Connection newConnection = null;
Channel createChannel = null;
try {
newConnection = connectionFactory.newConnection();
createChannel = newConnection.createChannel();
// 队列绑定交换机-channel.queueBind(队列名, 交换机名, 路由key[广播消息设置为空串])
createChannel.queueBind("myQueue", "order.dead.exchange", "routing_key_myQueue");
createChannel.basicConsume("myQueue", false, "", new DefaultConsumer(createChannel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties,
byte[] body) throws IOException {
System.out.println("时间： " + new Date());
System.out.println("consumerTag: " + consumerTag);
System.out.println("envelope: " + envelope);
System.out.println("properties: " + properties);
String string = new String(body, "UTF-8");
System.out.println("接收到消息： -》 " + string);
long deliveryTag = envelope.getDeliveryTag();
Channel channel = this.getChannel();
channel.basicAck(deliveryTag, true);
System.out.println("死信队列中处理完消息息");
}
});
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
}结果： 消费者一先正常监听到，basicReject为false拒绝后进入死信队列；消费者二监听的死信队列收到消息。
消费者一打出的日志如下：
consumerTag: amq.ctag-0noHs24F0FsGe-dfwwqWNw
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=order.exchange, routingKey=routing_key_myQueue)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers=null, delivery-mode=null, 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)
接收到消息： -》 测试消息
拒绝消息， 使之进入死信队列
时间： Sat Nov 07 12:18:44 CST 2020消费者二打出的日志如下：
时间： Sat Nov 07 12:18:47 CST 2020
consumerTag: amq.ctag-ajYMpMFkXHDiYWkD3XFJ7Q
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=order.dead.exchange, routingKey=routing_key_myQueue)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers={x-death=[{reason=rejected, count=1, exchange=order.exchange, time=Sat Nov 07 01:52:19 CST 2020, routing-keys=[routing_key_myQueue], queue=myQueue}]}, delivery-mode=null, 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)
接收到消息： -》 测试消息
死信队列中处理完消息息注意：
进入死信队列之后，headers 加了一些死信相关的信息，包括原队列以及进入死信的原因。
补充：在队列进入死信队列之前也可以修改其routingKey,而且只有在指定x-dead-letter-exchange的前提下才能修改下面属性，否则会报错
(1)修改生产者声明队列的方式，如下：
// 声明一个正常的direct类型的交换机
createChannel.exchangeDeclare("order.exchange", BuiltinExchangeType.DIRECT);
// 声明死信交换机为===order.dead.exchange
String dlxName = "order.dead.exchange";
createChannel.exchangeDeclare(dlxName, BuiltinExchangeType.DIRECT);
// 声明队列并指定死信交换机为上面死信交换机
Map<String, Object> arg = new HashMap<String, Object>();
arg.put("x-dead-letter-exchange", dlxName);
// 修改进入死信队列的routingkey，如果不修改会使用默认的routingKey
arg.put("x-dead-letter-routing-key", "routing_key_myQueue_dead");
createChannel.queueDeclare("myQueue", true, false, false, arg);(2)修改监听死信队列的消费者二：
// 队列绑定交换机-channel.queueBind(队列名, 交换机名, 路由key[广播消息设置为空串])
createChannel.queueBind("myQueue", "order.dead.exchange", "routing_key_myQueue_dead");结果，收到消费者二收到的信息如下：
时间： Sat Nov 07 12:27:08 CST 2020
consumerTag: amq.ctag-THqpEdYH_-iNeCIccgpuaw
envelope: Envelope(deliveryTag=1, redeliver=false, exchange=order.dead.exchange, routingKey=routing_key_myQueue_dead)
properties: #contentHeader<basic>(content-type=null, content-encoding=null, headers={x-death=[{reason=rejected, count=1, exchange=order.exchange, time=Sat Nov 07 02:00:41 CST 2020, routing-keys=[routing_key_myQueue], queue=myQueue}]}, delivery-mode=null, 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)
接收到消息： -》 测试消息
死信队列中处理完消息二、延时队列
延迟队列，即消息进入队列后不会立即被消费，只有到达指定时间后，才会被消费
RabbitMQ本身没提供延时队列，我们可以利用消息的生存时间和死信队列实现延时
典型的应用场景就是订单30分钟内未支付就关闭订单，还有一种场景，账单24小时未确认，就发送提醒消息
2.1.1、yml配置
spring:
rabbitmq:
host: 192.168.99.12
port: 5672
username: guest
password: guest
# 发送确认
publisher-confirms: true
# 路由失败回调
publisher-returns: true
template:
# 必须设置成true 消息路由失败通知监听者，false 将消息丢弃
mandatory: true
#消费端
listener:
simple:
# 每次从RabbitMQ获取的消息数量
prefetch: 1
default-requeue-rejected: false
# 每个队列启动的消费者数量
concurrency: 1
# 每个队列最大的消费者数量
max-concurrency: 1
# 签收模式为手动签收-那么需要在代码中手动ACK
acknowledge-mode: manual
#邮件队列
email:
queue:
name: demo.email
#邮件交换器名称
exchange:
name: demoTopicExchange
#死信队列
dead:
letter:
queue:
name: demo.dead.letter
exchange:
name: demoDeadLetterTopicExchange
#延时队列
delay:
queue:
name: demo.delay
exchange:
name: demoDelayTopicExchange
2.1.2、延时队列配置
/**
* rabbitmq 配置
*
* @author DUCHONG
* @since 2020-08-23 14:05
**/
@Configuration
@Slf4j
public class RabbitmqConfig {
@Value("${email.queue.name}")
private String emailQueue;
@Value("${exchange.name}")
private String topicExchange;
@Value("${dead.letter.queue.name}")
private String deadLetterQueue;
@Value("${dead.letter.exchange.name}")
private String deadLetterExchange;
@Value("${delay.queue.name}")
private String delayQueue;
@Value("${delay.exchange.name}")
private String delayExchange;
@Bean
public Queue emailQueue() {
Map<String, Object> arguments = new HashMap<>(2);
// 绑定死信交换机
arguments.put("x-dead-letter-exchange", deadLetterExchange);
// 绑定死信的路由key
arguments.put("x-dead-letter-routing-key", deadLetterQueue+".#");
return new Queue(emailQueue,true,false,false,arguments);
}
@Bean
TopicExchange emailExchange() {
return new TopicExchange(topicExchange);
}
@Bean
Binding bindingEmailQueue() {
return BindingBuilder.bind(emailQueue()).to(emailExchange()).with(emailQueue+".#");
}
//私信队列和交换器
@Bean
public Queue deadLetterQueue() {
return new Queue(deadLetterQueue);
}
@Bean
TopicExchange deadLetterExchange() {
return new TopicExchange(deadLetterExchange);
}
@Bean
Binding bindingDeadLetterQueue() {
return BindingBuilder.bind(deadLetterQueue()).to(deadLetterExchange()).with(deadLetterQueue+".#");
}
//延时队列
@Bean
public Queue delayQueue() {
return new Queue(delayQueue);
}
@Bean
CustomExchange delayExchange() {
Map<String, Object> args = new HashMap<>();
args.put("x-delayed-type", "topic");
//参数二为类型：必须是x-delayed-message
return new CustomExchange(delayExchange, "x-delayed-message", true, false, args);
}
@Bean
Binding bindingDelayQueue() {
return BindingBuilder.bind(delayQueue()).to(delayExchange()).with(delayQueue+".#").noargs();
}
}
2.2、消息发送方
30分钟时间太久了，这里延时2分钟来看效果
@Configuration
@EnableScheduling
@Slf4j
public class ScheduleController {
@Autowired
RabbitTemplate rabbitTemplate;
@Value("${exchange.name}")
private String topicExchange;
@Value("${delay.exchange.name}")
private String delayTopicExchange;
@Scheduled(cron = "0 0/1 * * * ?")
public void sendEmailMessage() {
String msg = RandomStringUtils.randomAlphanumeric(8);
JSONObject email=new JSONObject();
email.put("content",msg);
email.put("to","[email protected]");
CorrelationData correlationData=new CorrelationData(UUID.randomUUID().toString());
rabbitTemplate.convertAndSend(topicExchange,"demo.email.x",email.toJSONString(),correlationData);
log.info("---发送 email 消息---{}---messageId---{}",email,correlationData.getId());
}
@Scheduled(cron = "0 0/1 * * * ?")
public void sendDelayOrderMessage() throws Exception{
//订单号 id实际是保存订单后返回的，这里用uuid代替
String orderId = UUID.randomUUID().toString();
// 模拟订单信息
JSONObject order=new JSONObject();
order.put("orderId",orderId);
order.put("goodsName","vip充值");
order.put("orderAmount","99.00");
CorrelationData correlationData=new CorrelationData(orderId);
MessageProperties messageProperties = new MessageProperties();
messageProperties.setMessageId(orderId);
//30分钟时间太长，这里延时120s消费
messageProperties.setHeader("x-delay", 120000);
Message message = new Message(order.toJSONString().getBytes(CharEncoding.UTF_8), messageProperties);
rabbitTemplate.convertAndSend(delayTopicExchange,"demo.delay.x",message,correlationData);
log.info("---发送 order 消息---{}---orderId---{}",order,correlationData.getId());
//睡一会，为了看延迟效果
TimeUnit.MINUTES.sleep(10);
}
}
2.3、消息消费方
@Component
@Slf4j
public class MessageHandler {
/**
* 邮件发送
* @param message
* @param channel
* @param headers
* @throws IOException
*/
@RabbitListener(queues ="demo.email")
@RabbitHandler
public void handleEmailMessage(Message message, Channel channel, @Headers Map<String,Object> headers) throws IOException {
try {
String msg=new String(message.getBody(), CharEncoding.UTF_8);
JSONObject jsonObject = JSON.parseObject(msg);
jsonObject.put("messageId",headers.get("spring_returned_message_correlation"));
log.info("---接受到消息---{}",jsonObject);
//主动异常
int m=1/0;
//手动签收
channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);
}
catch (Exception e) {
log.info("handleEmailMessage捕获到异常,拒绝重新入队---消息ID---{}", headers.get("spring_returned_message_correlation"));
//异常，ture 重新入队,或者false,进入死信队列
channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,false);
}
}
/**
* 死信消费者，自动签收开启状态下，超过重试次数，或者手动签收，reject或者Nack
* @param message
*/
@RabbitListener(queues = "demo.dead.letter")
public void handleDeadLetterMessage(Message message, Channel channel,@Headers Map<String,Object> headers) throws IOException {
//可以考虑数据库记录，每次进来查数量，达到一定的数量，进行预警，人工介入处理
log.info("接收到死信消息:---{}---消息ID---{}", new String(message.getBody()),headers.get("spring_returned_message_correlation"));
//回复ack
channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);
}
/**
* 延时队列消费
* @param message
* @param channel
* @param headers
* @throws IOException
*/
@RabbitListener(queues ="demo.delay")
@RabbitHandler
public void handleOrderDelayMessage(Message message, Channel channel, @Headers Map<String,Object> headers) throws IOException {
try {
String msg=new String(message.getBody(), CharEncoding.UTF_8);
JSONObject jsonObject = JSON.parseObject(msg);
log.info("---接受到订单消息---orderId---{}",message.getMessageProperties().getMessageId());
log.info("---订单信息---order---{}",jsonObject);
//业务逻辑，根据订单id获取订单信息，如果还未支付，设置关闭状态，如果已支付，不做任何处理
//手动签收
channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);
}
catch (Exception e) {
log.info("handleOrderDelayMessage捕获到异常,重新入队---orderId---{}", headers.get("spring_returned_message_correlation"));
//异常，ture 重新入队,或者false,进入死信队列
channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,true);
}
}
}
2.4、结果
运行结果显示，同一个订单号的消息，发送过后2分钟，消费者才接受到，符合预期
https://www.cnblogs.com/geekdc/p/13550620.html