RabbitMQ死信队列

死性队列的基本介绍

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 或有且按到quee工,出曲a这样的当自如里没有进行消费，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

死信队列的来源

消息TTL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.

代码架构图

死性队列（消费者1）

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
import java.util.HashMap;

/**
 * 死性队列
 *
 * 消费者1
 */
public class Consumer01 {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    //死性队列交换机的名称
    public static final String DEAD_EXCHANGE="dead_exchange";
    //普通队列的名称
    public static final String NORMAL_QUEUE = "normal_queue";
    //死性队列名称
    public static final String DEAD_QUEUE="dead_queue";

    public static void main(String[] args) throws Exception{
        Channel channel = RabbitMqUtils.getChannel();
        //声明死性队列和普通队列交换机的类型未direct
        channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);
        channel.exchangeDeclare(DEAD_EXCHANGE,BuiltinExchangeType.DIRECT);
        //声明普通队列
        HashMap<String, Object> arguments = new HashMap<>();
        //过期时间 10s=10000ms
        //arguments.put("x-message-ttl",100000);
        //正常队列设置死性队列交换机
        arguments.put("x-dead-letter-exchange",DEAD_EXCHANGE);
        //设置死性RoutingKey
        arguments.put("x-dead-letter-routing-key","lisi");
        channel.queueDeclare(NORMAL_QUEUE,false,false,false,arguments);
        ////////////////////////////////////////////////////////////////////////
        //声明死性队列
        channel.queueDeclare(DEAD_QUEUE,false,false,false,null);
        //绑定普通的交换机与普通的队列
        channel.queueBind(NORMAL_QUEUE,NORMAL_EXCHANGE,"zhangsan");
        channel.queueBind(DEAD_QUEUE, DEAD_EXCHANGE, "lisi");
        System.out.println("等待接收消息......");

       DeliverCallback deliverCallback=((consumerTag, message) -> {
           System.out.println("Consumer01接收的消息是："+new String(message.getBody(),"utf-8"));
       });
       channel.basicConsume(NORMAL_QUEUE,true,deliverCallback,consumerTag ->{});
    }
}

死性队列（生产者）

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
/*
死性队列生产者
 */
public class Producer {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        //死性队列 设置TTL时间 单位是ms 10000ms=10s
        AMQP.BasicProperties properties=new AMQP.BasicProperties()
                .builder().expiration("10000").build();
        for (int i = 1; i <11;i++ ) {
          String msg="info"+i;
          channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",properties,msg.getBytes("utf-8"));
        }
    }
}

死性队列（消费者2）

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
import java.util.HashMap;

/**
 * 死性队列
 * 消费者2
 */
public class Consumer02 {
    //死性队列名称
    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=((consumerTag, message) -> {
           System.out.println("Consumer02接收的消息是："+new String(message.getBody(),"utf-8"));
       });
       channel.basicConsume(DEAD_QUEUE,true,deliverCallback,consumerTag ->{});
    }
}

死性队列队（列达到最大长度）

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.Channel;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
/*
死性队列生产者
 */
public class Producer {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        //死性队列 设置TTL时间 单位是ms 10000ms=10s
//        AMQP.BasicProperties properties=new AMQP.BasicProperties()
//                .builder().expiration("10000").build();
        for (int i = 1; i <11;i++ ) {
          String msg="info"+i;
          channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null,msg.getBytes("utf-8"));
        }

    }
}

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
import java.util.HashMap;

/**
 * 死性队列
 *
 * 消费者1（把之前的normal_queue删了，因为已存在）
 */
public class Consumer01 {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    //死性队列交换机的名称
    public static final String DEAD_EXCHANGE="dead_exchange";
    //普通队列的名称
    public static final String NORMAL_QUEUE = "normal_queue";
    //死性队列名称
    public static final String DEAD_QUEUE="dead_queue";

    public static void main(String[] args) throws Exception{
        Channel channel = RabbitMqUtils.getChannel();
        //声明死性队列和普通队列交换机的类型未direct
        channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);
        channel.exchangeDeclare(DEAD_EXCHANGE,BuiltinExchangeType.DIRECT);
        //声明普通队列
        HashMap<String, Object> arguments = new HashMap<>();
        //过期时间 10s=10000ms
        //arguments.put("x-message-ttl",100000);
        //正常队列设置死性队列交换机
        arguments.put("x-dead-letter-exchange",DEAD_EXCHANGE);
        //设置死性RoutingKey
        arguments.put("x-dead-letter-routing-key","lisi");
        //设置正常队列限制消息最大为6条
        arguments.put("x-max-length",6);

        channel.queueDeclare(NORMAL_QUEUE,false,false,false,arguments);

        ////////////////////////////////////////////////////////////////////////
        //声明死性队列
        channel.queueDeclare(DEAD_QUEUE,false,false,false,null);
        //绑定普通的交换机与普通的队列
        channel.queueBind(NORMAL_QUEUE,NORMAL_EXCHANGE,"zhangsan");
        channel.queueBind(DEAD_QUEUE, DEAD_EXCHANGE, "lisi");
        System.out.println("等待接收消息......");

       DeliverCallback deliverCallback=((consumerTag, message) -> {
           System.out.println("Consumer01接收的消息是："+new String(message.getBody(),"utf-8"));
       });
       channel.basicConsume(NORMAL_QUEUE,true,deliverCallback,consumerTag ->{});
    }
}

死性队列（消息被拒）

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.Channel;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
/*
死性队列生产者
 */
public class Producer {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    public static void main(String[] args) throws Exception {
        Channel channel = RabbitMqUtils.getChannel();
        //死性队列 设置TTL时间 单位是ms 10000ms=10s
//        AMQP.BasicProperties properties=new AMQP.BasicProperties()
//                .builder().expiration("10000").build();
        for (int i = 1; i <11;i++ ) {
          String msg="info"+i;
          channel.basicPublish(NORMAL_EXCHANGE,"zhangsan",null,msg.getBytes("utf-8"));
        }

    }
}

package com.yuan.rabbitmq.seven;
import com.rabbitmq.client.BuiltinExchangeType;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;
import com.yuan.rabbitmq.utils.RabbitMqUtils;
import java.util.HashMap;

/**
 * 死性队列
 *
 * 消费者1（把之前的normal_queue删了，因为已存在）
 */
public class Consumer01 {
    //普通交换机的名称
    public static final String NORMAL_EXCHANGE="normal_exchange";
    //死性队列交换机的名称
    public static final String DEAD_EXCHANGE="dead_exchange";
    //普通队列的名称
    public static final String NORMAL_QUEUE = "normal_queue";
    //死性队列名称
    public static final String DEAD_QUEUE="dead_queue";

    public static void main(String[] args) throws Exception{
        Channel channel = RabbitMqUtils.getChannel();
        //声明死性队列和普通队列交换机的类型未direct
        channel.exchangeDeclare(NORMAL_EXCHANGE, BuiltinExchangeType.DIRECT);
        channel.exchangeDeclare(DEAD_EXCHANGE,BuiltinExchangeType.DIRECT);
        //声明普通队列
        HashMap<String, Object> arguments = new HashMap<>();
        //过期时间 10s=10000ms
        //arguments.put("x-message-ttl",100000);
        //正常队列设置死性队列交换机
        arguments.put("x-dead-letter-exchange",DEAD_EXCHANGE);
        //设置死性RoutingKey
        arguments.put("x-dead-letter-routing-key","lisi");
        //设置正常队列限制消息最大为6条

        channel.queueDeclare(NORMAL_QUEUE,false,false,false,arguments);

        ////////////////////////////////////////////////////////////////////////
        //声明死性队列
        channel.queueDeclare(DEAD_QUEUE,false,false,false,null);
        //绑定普通的交换机与普通的队列
        channel.queueBind(NORMAL_QUEUE,NORMAL_EXCHANGE,"zhangsan");
        channel.queueBind(DEAD_QUEUE, DEAD_EXCHANGE, "lisi");
        System.out.println("等待接收消息......");

       DeliverCallback deliverCallback=((consumerTag, message) -> {
           String meg=new String(message.getBody(),"utf-8");
           //如果消息为info5就拒绝
           if (meg.equals("info5")) {
               System.out.println("Consumer01接收的消息是："+meg+"此消息是被C1拒绝的");
               channel.basicReject(message.getEnvelope().getDeliveryTag(),false);
           }else {
               System.out.println("Consumer01接收的消息是："+meg);
               channel.basicAck(message.getEnvelope().getDeliveryTag(),false);
           }

       });
       //开启手动应答
       channel.basicConsume(NORMAL_QUEUE,false,deliverCallback,consumerTag ->{});
    }
}