目錄

成為死信的條件?

消息TTL過(guò)期?

?隊(duì)列達(dá)到最大長(zhǎng)度

?消息被拒

延遲隊(duì)列

?延遲隊(duì)列使用場(chǎng)景

?消息設(shè)置 TTL

隊(duì)列設(shè)置 TTL

?兩者區(qū)別

---

?

producer 將消息投遞到 broker 或者直接到 queue 里了， consumer 從 queue 取出消息

進(jìn)行消費(fèi)，但某些時(shí)候由于特定的 原因?qū)е? queue 中的某些消息無(wú)法被消費(fèi) ，這樣的消息如果沒(méi)有后續(xù)的處理，就變成了死信，有死信自然就有了死信隊(duì)列。

成為死信的條件?

1. 超過(guò)消息的存活時(shí)間（TTL）：可以為消息設(shè)置一個(gè)存活時(shí)間，在該時(shí)間段之后，如果消息還未被消費(fèi)或者被重新投遞到其他隊(duì)列，該消息將成為死信。

2. 消息被拒絕（Reject）：當(dāng)消息被消費(fèi)者拒絕接收時(shí)，可以選擇將該消息重新投遞到另一個(gè)隊(duì)列或?qū)⑵錁?biāo)記為死信。

3. 消息達(dá)到最大重試次數(shù)：可以通過(guò)在消費(fèi)者端設(shè)置重試次數(shù)限制，當(dāng)消息達(dá)到一定的重試次數(shù)而仍然無(wú)法被消費(fèi)時(shí)，該消息將成為死信。

4. 隊(duì)列滿溢（Queue Overflow）：當(dāng)一個(gè)隊(duì)列的消息數(shù)量已經(jīng)超過(guò)隊(duì)列的最大容量限制時(shí)，新消息無(wú)法進(jìn)入隊(duì)列，而被視為死信。

?

消息TTL過(guò)期?

生產(chǎn)者?

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;public class Producer {private static final String NORMAL_EXCHANGE = "normal_exchange";public static void main(String[] argv) throws Exception {try (Channel channel = RabbitMqUtils.getChannel()) {channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);//設(shè)置消息的 TTL 時(shí)間AMQP.BasicProperties properties = new AMQP.BasicProperties().builder().expiration("10000").build();//該信息是用作演示隊(duì)列個(gè)數(shù)限制for (int i = 1; i <11 ; i++) {String message="info"+i;channel.basicPublish(NORMAL_EXCHANGE, "zhangsan", properties,message.getBytes());System.out.println("生產(chǎn)者發(fā)送消息:"+message);}}}
}

?消費(fèi)者1

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;import java.util.HashMap;
import java.util.Map;public class Consumer01 {//普通交換機(jī)名稱private static final String NORMAL_EXCHANGE = "normal_exchange";//死信交換機(jī)名稱private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();//聲明死信和普通交換機(jī) 類型為 directchannel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);//聲明死信隊(duì)列String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);//死信隊(duì)列綁定死信交換機(jī)與 routingkeychannel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");//正常隊(duì)列綁定死信隊(duì)列信息Map<String, Object> params = new HashMap<>();//正常隊(duì)列設(shè)置死信交換機(jī) 參數(shù) key 是固定值params.put("x-dead-letter-exchange", DEAD_EXCHANGE);//正常隊(duì)列設(shè)置死信 routing-key 參數(shù) key 是固定值params.put("x-dead-letter-routing-key", "lisi");String normalQueue = "normal-queue";channel.queueDeclare(normalQueue, false, false, false, params);channel.queueBind(normalQueue, NORMAL_EXCHANGE, "zhangsan");System.out.println("等待接收消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("Consumer01 接收到消息"+message);};channel.basicConsume(normalQueue, true, deliverCallback, consumerTag -> {});}
}

消費(fèi)者2

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;public class Consumer02 {private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);channel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");System.out.println("等待接收死信隊(duì)列消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("Consumer02 接收死信隊(duì)列的消息" + message);};channel.basicConsume(deadQueue, true, deliverCallback, consumerTag -> {});}
}

關(guān)閉消費(fèi)者1，模擬出故障

正常隊(duì)列

?消息超時(shí)進(jìn)入死信隊(duì)列

?死信隊(duì)列接收信息

?隊(duì)列達(dá)到最大長(zhǎng)度

生產(chǎn)者

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;public class Producer {private static final String NORMAL_EXCHANGE = "normal_exchange";public static void main(String[] argv) throws Exception {try (Channel channel = RabbitMqUtils.getChannel()) {channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);//該信息是用作演示隊(duì)列個(gè)數(shù)限制for (int i = 1; i <11 ; i++) {String message="info"+i;channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null, message.getBytes());System.out.println("生產(chǎn)者發(fā)送消息:"+message);}}}
}

?消費(fèi)者1

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;import java.util.HashMap;
import java.util.Map;public class Consumer01 {//普通交換機(jī)名稱private static final String NORMAL_EXCHANGE = "normal_exchange";//死信交換機(jī)名稱private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();//聲明死信和普通交換機(jī) 類型為 directchannel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);//聲明死信隊(duì)列String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);//死信隊(duì)列綁定死信交換機(jī)與 routingkeychannel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");//正常隊(duì)列綁定死信隊(duì)列信息Map<String, Object> params = new HashMap<>();//正常隊(duì)列設(shè)置死信交換機(jī) 參數(shù) key 是固定值params.put("x-dead-letter-exchange", DEAD_EXCHANGE);//正常隊(duì)列設(shè)置死信 routing-key 參數(shù) key 是固定值params.put("x-dead-letter-routing-key", "lisi");// 設(shè)置正常隊(duì)列長(zhǎng)度的限制params.put("x-max-length",6);String normalQueue = "normal-queue";channel.queueDeclare(normalQueue, false, false, false, params);channel.queueBind(normalQueue, NORMAL_EXCHANGE, "zhangsan");System.out.println("等待接收消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("Consumer01 接收到消息"+message);};channel.basicConsume(normalQueue, true, deliverCallback, consumerTag -> {});}
}

?消費(fèi)者2

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;public class Consumer02 {private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);channel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");System.out.println("等待接收死信隊(duì)列消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("Consumer02 接收死信隊(duì)列的消息" + message);};channel.basicConsume(deadQueue, true, deliverCallback, consumerTag -> {});}
}

關(guān)閉消費(fèi)者1，模擬接收不到信息

?死信隊(duì)列消費(fèi)了四個(gè)消息

?分析：生產(chǎn)者產(chǎn)生10個(gè)消息，正常隊(duì)列只能接受6個(gè)消息，多的消息便被轉(zhuǎn)移到死信隊(duì)列去了

?消息被拒

生產(chǎn)者

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;public class Producer {private static final String NORMAL_EXCHANGE = "normal_exchange";public static void main(String[] argv) throws Exception {try (Channel channel = RabbitMqUtils.getChannel()) {channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);//該信息是用作演示隊(duì)列個(gè)數(shù)限制for (int i = 1; i <11 ; i++) {String message="info"+i;channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null, message.getBytes());System.out.println("生產(chǎn)者發(fā)送消息:"+message);}}}
}

消費(fèi)者1

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;import java.util.HashMap;
import java.util.Map;public class Consumer01 {//普通交換機(jī)名稱private static final String NORMAL_EXCHANGE = "normal_exchange";//死信交換機(jī)名稱private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();//聲明死信和普通交換機(jī) 類型為 directchannel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);//聲明死信隊(duì)列String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);//死信隊(duì)列綁定死信交換機(jī)與 routingkeychannel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");//正常隊(duì)列綁定死信隊(duì)列信息Map<String, Object> params = new HashMap<>();//正常隊(duì)列設(shè)置死信交換機(jī) 參數(shù) key 是固定值params.put("x-dead-letter-exchange", DEAD_EXCHANGE);//正常隊(duì)列設(shè)置死信 routing-key 參數(shù) key 是固定值params.put("x-dead-letter-routing-key", "lisi");String normalQueue = "normal-queue";channel.queueDeclare(normalQueue, false, false, false, params);channel.queueBind(normalQueue, NORMAL_EXCHANGE, "zhangsan");System.out.println("等待接收消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");if(message.equals("info5")){System.out.println("Consumer01 接收到消息" + message + "并拒絕簽收該消息");//requeue 設(shè)置為 false 代表拒絕重新入隊(duì) 該隊(duì)列如果配置了死信交換機(jī)將發(fā)送到死信隊(duì)列中channel.basicReject(delivery.getEnvelope().getDeliveryTag(), false);}else {System.out.println("Consumer01 接收到消息"+message);channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);}};boolean autoAck = false;channel.basicConsume(normalQueue, autoAck, deliverCallback, consumerTag -> {});}
}

?消費(fèi)者2

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;public class Consumer02 {private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);channel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");System.out.println("等待接收死信隊(duì)列消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");System.out.println("Consumer02 接收死信隊(duì)列的消息" + message);};channel.basicConsume(deadQueue, true, deliverCallback, consumerTag -> {});}
}

?結(jié)果

消費(fèi)者1，拒絕接受消息info5，info5進(jìn)入死信隊(duì)列

?消費(fèi)者2，死信隊(duì)列接受到info5

延遲隊(duì)列

?延遲隊(duì)列使用場(chǎng)景

?消息設(shè)置 TTL

?

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;public class Producer {private static final String NORMAL_EXCHANGE = "normal_exchange";public static void main(String[] argv) throws Exception {try (Channel channel = RabbitMqUtils.getChannel()) {channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);//設(shè)置消息的 TTL 時(shí)間AMQP.BasicProperties properties = new AMQP.BasicProperties().builder().expiration("10000").build();//該信息是用作演示隊(duì)列個(gè)數(shù)限制for (int i = 1; i <11 ; i++) {String message="info"+i;channel.basicPublish(NORMAL_EXCHANGE, "zhangsan", properties,message.getBytes());System.out.println("生產(chǎn)者發(fā)送消息:"+message);}}}
}

隊(duì)列設(shè)置 TTL

import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;import java.util.HashMap;
import java.util.Map;public class Consumer01 {//普通交換機(jī)名稱private static final String NORMAL_EXCHANGE = "normal_exchange";//死信交換機(jī)名稱private static final String DEAD_EXCHANGE = "dead_exchange";public static void main(String[] argv) throws Exception {Channel channel = RabbitMqUtils.getChannel();//聲明死信和普通交換機(jī) 類型為 directchannel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);//聲明死信隊(duì)列String deadQueue = "dead-queue";channel.queueDeclare(deadQueue, false, false, false, null);//死信隊(duì)列綁定死信交換機(jī)與 routingkeychannel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");//正常隊(duì)列綁定死信隊(duì)列信息Map<String, Object> params = new HashMap<>();//正常隊(duì)列設(shè)置死信交換機(jī) 參數(shù) key 是固定值params.put("x-dead-letter-exchange", DEAD_EXCHANGE);//正常隊(duì)列設(shè)置死信 routing-key 參數(shù) key 是固定值params.put("x-dead-letter-routing-key", "lisi");// 設(shè)置 TTL 值為 5000 毫秒（5 秒）params.put("x-message-ttl", 5000);String normalQueue = "normal-queue";channel.queueDeclare(normalQueue, false, false, false, params);channel.queueBind(normalQueue, NORMAL_EXCHANGE, "zhangsan");System.out.println("等待接收消息.....");DeliverCallback deliverCallback = (consumerTag, delivery) -> {String message = new String(delivery.getBody(), "UTF-8");if(message.equals("info5")){System.out.println("Consumer01 接收到消息" + message + "并拒絕簽收該消息");//requeue 設(shè)置為 false 代表拒絕重新入隊(duì) 該隊(duì)列如果配置了死信交換機(jī)將發(fā)送到死信隊(duì)列中channel.basicReject(delivery.getEnvelope().getDeliveryTag(), false);}else {System.out.println("Consumer01 接收到消息"+message);channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);}};boolean autoAck = false;channel.basicConsume(normalQueue, autoAck, deliverCallback, consumerTag -> {});}
}

?兩者區(qū)別

?