RibbitMQ学习笔记之死信队列

默语

发布于 2024-11-20 10:54:54

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RibbitMQ学习笔记之死信队列

6. 死信队列

6.1. 死信的概念

先从概念解释上搞清楚这个定义，死信，顾名思义就是无法被消费的消息，字面意思可以这样理解，一般来说，producer 将消息投递到 broker 或者直接到queue 里了，consumer 从 queue 取出消息进行消费，但某些时候由于特定的原因导致 queue 中的某些消息无法被消费，这样的消息如果没有后续的处理，就变成了死信，有死信自然就有了死信队列。

应用场景:为了保证订单业务的消息数据不丢失，需要使用到 RabbitMQ 的死信队列机制，当消息消费发生异常时，将消息投入死信队列中.还有比如说: 用户在商城下单成功并点击去支付后在指定时间未支付时自动失效

6.2. 死信的来源

消息 TTL 过期消息存活时间过期
队列达到最大长度(队列满了，无法再添加数据到 mq 中)
消息被拒绝(basic.reject 或 basic.nack)并且 requeue=false. 拒绝应答不放在队列中也会在死信中

6.3. 死信实战

6.3.1. 代码架构图

6.3.2. 消息 TTL 过期

生产者代码

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);
 


//设置消息的 TTL 时间 newAMQP.BasicProperties().builder().expiration("10000").build(); //该信息是用作演示队列个数限制  for (int i = 1; i <11 ; i++) {  String message="info"+i;  channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",properties,message.getBytes());  
 
System.out.println("生产者发送消息:"+message);
 
}
 
}
}
}

package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

/**
 * 死信队列  生产者
 */
public class Producer {

    //普通交换机 名称
    public static final String NORMAL_EXCHANGE="normal_exchange";

    public static void main(String[] args) throws IOException, TimeoutException {
        Channel channel = RabbitMqutils.getChannel();
       //死信消息 设置TTl  单位是ms 100000ms=10s
        AMQP.BasicProperties basicProperties =
                new AMQP.BasicProperties()
                        .builder().expiration("1000").build();

        for (int i = 0; i < 11; i++) {
            String message="info"+i;

            channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",basicProperties,message.getBytes());

        }





    }

}

消费者 C1 代码(启动之后关闭该消费者模拟其接收不到消息)

public class Consumer01 {
//普通交换机名称
 
private static final String NORMAL_EXCHANGE = "normal_exchange";
//死信交换机名称
 
private static final String DEAD_EXCHANGE = "dead_exchange"; public static void main(String[] argv) throws Exception {
Channel channel = RabbitUtils.getChannel();


//声明死信和普通交换机 类型为 direct channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT); channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);
 
//声明死信队列
 
String deadQueue = "dead-queue"; 
channel.queueDeclare(deadQueue, false, false, false, null);
 
//死信队列绑定死信交换机与 routingkey channel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");
 
//正常队列绑定死信队列信息
 
Map<String, Object> params = new HashMap<>();
 
//正常队列设置死信交换机 参数 key 是固定值 params.put("x-dead-letter-exchange", DEAD_EXCHANGE);
 
//正常队列设置死信 routing-key 参数 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 -> { });
 
}
 
}

 package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;

import java.util.HashMap;
import java.util.Map;

/**
 * 死信队列
 * 消费者 1
 * 大小写切换 ctrl+shirft+u
 */
public class Consumer01 {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE = "normal_exchange";
    //死信交换机的名称
    public static final String DEAD_EXCHANGE = "dead_exchange";
    //普通队列的名称
    public static final String NORMAL_QUEUE = "normal_queue";
    //死信队列的名称
    public static final String DEAD_QUEUE = "dead_queue";


    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqutils.getChannel();
        //声明死信交换机 类型为direct  1.交换机的名字  2.交换机的类型
        channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);
        //声明普通交换机 类型为direct
        channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);
        /**
         *          * 生成一个队列
         *          * 1.队列名称
         *          * 2.队列中的消息是否持久化  默认消息存储在内存中 否不持久化 （持久化放在磁盘中）
         *          *3.该队列是否只供一个消费者进行消费 是否共享  true 可以多个消费者消费  默认false,只能一个消费者消费
         *          4.是否自动删除 最后一个消费者端开连接以后 该队列是否自动删除 true自动删除 false不删除
         *          5.其他参数
         *
         */

        //声明死信队列
        channel.queueDeclare(DEAD_QUEUE, false, false, false, null);

        //声明普通队列
        Map<String, Object> arguments = new HashMap<>();
        //过期时间   10s=100000ms
        // arguments.put("x-message-ttl",100000);
        //正常队列设置死信交换机        1.值  2.死信交换机名字
        arguments.put("x-dead-letter-exchange", DEAD_EXCHANGE);
        //设置死信RoutingKey
        arguments.put("x-dead-letter-routing-key", "lisi");
        //声明普通队列
        channel.queueDeclare(NORMAL_QUEUE, false, false, false, arguments);

        //绑定普通的交换机与偶有普通的队列
        channel.queueBind(NORMAL_QUEUE,NORMAL_EXCHANGE,"zhangsan");
        //绑定死信的交换机与偶有死信的队列
        channel.queueBind(DEAD_QUEUE,DEAD_EXCHANGE,"lisi");
        System.out.println("等待接收消息.......");

        DeliverCallback deliverCallback = (var1, var2) -> {
            System.out.println("Consumer01" + new String(var2.getBody(), "utf-8"));
        };
        channel.basicConsume(NORMAL_QUEUE, true, deliverCallback, var1 -> {
        });

    }


}

消费者 C2 代码(以上步骤完成后启动 C2 消费者它消费死信队列里面的消息)

public class Consumer02 {
 
private static final String DEAD_EXCHANGE = "dead_exchange"; 
public static void main(String[] argv) throws Exception {



Channel channel = RabbitUtils.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("等待接收死信队列消息 ........... "); 
DeliverCallback deliverCallback = (consumerTag, delivery) ->
 
{ String message = new String(delivery.getBody(), "UTF-8"); 
System.out.println("Consumer02 接收死信队列的消息" + message);
};
 
channel.basicConsume(deadQueue, true, deliverCallback, consumerTag -> { });
}
}

 package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;

import java.util.HashMap;
import java.util.Map;

/**
 * 死信队列
 * 消费者 1
 * 大小写切换 ctrl+shirft+u
 */
public class Consumer02 {

    //死信队列的名称
    public static final String DEAD_QUEUE = "dead_queue";


    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqutils.getChannel();

        System.out.println("等待接收消息.......");

        DeliverCallback deliverCallback = (var1, var2) -> {
            System.out.println("Consumer02" + new String(var2.getBody(), "utf-8"));
        };
        channel.basicConsume(DEAD_QUEUE, true, deliverCallback, var1 -> {
        });

    }


}

6.3.3. 队列达到最大长度

1. 消息生产者代码去掉 TTL 属性

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);
 
//该信息是用作演示队列个数限制
 
for (int i = 1; i <11 ; i++) {
 String message="info"+i;
 
channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null, message.getBytes());
 System.out.println("生产者发送消息:"+message);
 
}
}
}
 
}

2. C1 消费者修改以下代码(启动之后关闭该消费者模拟其接收不到消息

注意此时需要把原先队列删除因为参数改变了

C2 消费者代码不变(启动 C2 消费者)

6.3.4. 消息被拒

消息生产者代码同上生产者一致
C1 消费者代码(启动之后关闭该消费者模拟其接收不到消息)

public class Consumer01 {
//普通交换机名称
 
private static final String NORMAL_EXCHANGE = "normal_exchange";
//死信交换机名称
 
private static final String DEAD_EXCHANGE = "dead_exchange"; public static void main(String[] argv) throws Exception {
 
Channel channel = RabbitUtils.getChannel();
 
//声明死信和普通交换机 类型为 direct channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT); channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);
 
//声明死信队列
 
String deadQueue = "dead-queue"; channel.queueDeclare(deadQueue, false, false, false, null);
 
//死信队列绑定死信交换机与 routingkey channel.queueBind(deadQueue, DEAD_EXCHANGE, "lisi");



//正常队列绑定死信队列信息
 
Map<String, Object> params = new HashMap<>();
 
//正常队列设置死信交换机 参数 key 是固定值 params.put("x-dead-letter-exchange", DEAD_EXCHANGE);
 
//正常队列设置死信 routing-key 参数 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  +                                                                                       "并拒绝签收该消息");
 
//requeue 设置为 false 代表拒绝重新入队 该队列如果配置了死信交换机将发送到死信队列中 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 -> { });
}
 
}

C2 消费者代码不变

启动消费者 1 然后再启动消费者 2

上面3个部分内容代码整理如下：

package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;

import java.util.HashMap;
import java.util.Map;

/**
 * 死信队列
 * 消费者 1
 * 大小写切换 ctrl+shirft+u
 */
public class Consumer01 {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE = "normal_exchange";
    //死信交换机的名称
    public static final String DEAD_EXCHANGE = "dead_exchange";
    //普通队列的名称
    public static final String NORMAL_QUEUE = "normal_queue";
    //死信队列的名称
    public static final String DEAD_QUEUE = "dead_queue";


    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqutils.getChannel();
        //声明死信交换机 类型为direct  1.交换机的名字  2.交换机的类型
        channel.exchangeDeclare(DEAD_EXCHANGE, BuiltinExchangeType.DIRECT);
        //声明普通交换机 类型为direct
        channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);
        /**
         *          * 生成一个队列
         *          * 1.队列名称
         *          * 2.队列中的消息是否持久化  默认消息存储在内存中 否不持久化 （持久化放在磁盘中）
         *          *3.该队列是否只供一个消费者进行消费 是否共享  true 可以多个消费者消费  默认false,只能一个消费者消费
         *          4.是否自动删除 最后一个消费者端开连接以后 该队列是否自动删除 true自动删除 false不删除
         *          5.其他参数
         *
         */


        //声明普通队列
        Map<String, Object> arguments = new HashMap<>();
        //过期时间   10s=100000ms
       //  arguments.put("x-message-ttl",100000);
        //正常队列设置死信交换机        1.值  2.死信交换 机名字
        arguments.put("x-dead-letter-exchange", DEAD_EXCHANGE);
        //设置死信RoutingKey
        arguments.put("x-dead-letter-routing-key", "lisi");
        //设置正常队列长度的限制
        //arguments.put("x-max-length",6);

        //声明普通队列
        channel.queueDeclare(NORMAL_QUEUE, false, false, false,arguments);

        //声明死信队列
        channel.queueDeclare(DEAD_QUEUE, false, false, false, null);

        //绑定普通的交换机与偶有普通的队列
        channel.queueBind(NORMAL_QUEUE,NORMAL_EXCHANGE,"zhangsan");
        //绑定死信的交换机与偶有死信的队列
        channel.queueBind(DEAD_QUEUE,DEAD_EXCHANGE,"lisi");
        System.out.println("等待接收消息.......");

        DeliverCallback deliverCallback = (var1, var2) -> {
           String msg= new String(var2.getBody(), "utf-8");
           if (msg.equals("info5")){
               System.out.println("Consumer01接受的消息是"+msg+"消息是被拒绝的");
               // 1.获取到值 2.不放回普通队列
               channel.basicReject(var2.getEnvelope().getDeliveryTag(),false );
           }else {
               System.out.println("Consumer01接受的消息是" +msg);
               channel.basicReject(var2.getEnvelope().getDeliveryTag(),false );
           }


        };
     //   channel.basicConsume(NORMAL_QUEUE, true, deliverCallback, var1 -> {});
        channel.basicConsume(NORMAL_QUEUE, false, deliverCallback, var1 -> {});
    }


}

 package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;

import java.util.HashMap;
import java.util.Map;

/**
 * 死信队列
 * 消费者 1
 * 大小写切换 ctrl+shirft+u
 */
public class Consumer02 {

    //死信队列的名称
    public static final String DEAD_QUEUE = "dead_queue";


    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqutils.getChannel();

        System.out.println("等待接收消息.......");

        DeliverCallback deliverCallback = (var1, var2) -> {
            System.out.println("Consumer02" + new String(var2.getBody(), "utf-8"));
        };
        channel.basicConsume(DEAD_QUEUE, true, deliverCallback, var1 -> {
        });

    }


}

生产者

 package com.atguigu.rabbitmq.eight;

import com.atguigu.rabbitmq.utils.RabbitMqutils;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

/**
 * 死信队列  生产者
 */
public class Producer {

    //普通交换机 名称
    public static final String NORMAL_EXCHANGE="normal_exchange";

    public static void main(String[] args) throws IOException, TimeoutException {
        Channel channel = RabbitMqutils.getChannel();
       //死信消息 设置TTl  单位是ms 100000ms=10s  过期时间
//        AMQP.BasicProperties basicProperties =
//                new AMQP.BasicProperties()
//                        .builder().expiration("1000").build();

        for (int i = 1; i < 11; i++) {
            String message="info"+i;
            channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null,message.getBytes());
          //  channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",basicProperties,message.getBytes());
            System.out.println("生产者发送消息"+message);
        }





    }

}

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原始发表：2022-11-21，如有侵权请联系 cloudcommunity@tencent.com 删除

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