RabbitMQ消费限流、重回队列、TTL和死信队列

于 2019-12-25 01:39:17 发布
阅读量286 收藏
点赞数
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/weixin_45174624/article/details/103691921
版权
本文详细介绍了RabbitMQ中消费端限流的原理与设置，强调了prefetchCount在手动ACK机制中的作用。接着探讨了消息的ACK确认与重回队列策略，建议在大多数情况下关闭重回队列以避免反复失败。接着，解释了TTL（Time To Live）功能，展示了如何设置消息和队列的过期时间。最后，阐述了死信队列（DLX）的概念，包括消息成为死信的条件及如何配置和利用死信队列进行异常处理。

摘要生成于 C知道 ，由 DeepSeek-R1 满血版支持， 前往体验 >

目录

消费端限流
消息的ACK与重回队列
TTL消息
死信队列

消费端限流

假设一个场景，由于我们的消费端突然全部不可用了，导致 rabbitMQ 服务器上有上万条未处理的消息，这时候如果没做任何现在，随便开启一个消费端客户端，就会导致巨量的消息瞬间全部推送过来，但是我们单个客户端无法同时处理这么多的数据，就会导致消费端变得巨卡，有可能直接崩溃不可用了
prefetchSize：0
prefetchCount：会告诉 RabbitMQ 不要同时给一个消费者推送多于 N 个消息，即一旦有 N 个消息还没有 ack，则该
consumer 将 block 掉，直到有消息 ack
global：true、false 是否将上面设置应用于 channel，简单点说，就是上面限制是 channel 级别的还是
consumer 级别
备注：prefetchSize 和 global 这两项，rabbitmq没有实现，暂且不研究。
特别注意一点，prefetchCount 在 no_ask=false的情况下才生效，即在自动应答的情况下这两个值是不生效的。

Consumer

package com.liuxia.rabbitmqapi.limit;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;


public class Consumer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();


        String exchangeName = "test_qos_exchange";
        String queueName = "test_qos_queue";
        String routingKey = "qos.#";

        channel.exchangeDeclare(exchangeName, "topic", true, false, null);
        channel.queueDeclare(queueName, true, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);

        //1 限流方式  第一件事就是 autoAck设置为 false
        channel.basicQos(0, 1, false);

        channel.basicConsume(queueName, false, new MyConsumer(channel));
    }
}

MyConsumer

package com.liuxia.rabbitmqapi.limit;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

import java.io.IOException;


public class MyConsumer extends DefaultConsumer {
    private Channel channel ;

    public MyConsumer(Channel channel) {
        super(channel);
        this.channel = channel;
    }

    @Override
    public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
        System.err.println("-----------consume message----------");
        System.err.println("consumerTag: " + consumerTag);
        System.err.println("envelope: " + envelope);
        System.err.println("properties: " + properties);
        System.err.println("body: " + new String(body));

        channel.basicAck(envelope.getDeliveryTag(), false);
    }

}

Producer

package com.liuxia.rabbitmqapi.limit;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;


public class Producer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();

        String exchange = "test_qos_exchange";
        String routingKey = "qos.save";

        String msg = "Hello RabbitMQ QOS Message";

        for(int i =0; i<5; i ++){
            channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());
        }

    }
}

我们启动消费者，发现只消费了一条消息
在这里插入图片描述

消息的ACK与重回队列

消费端手工ACK与NACK
消费端进行消费的时候，如果由于业务异常我们可以进行日志的记录，然后进行补偿
如果由于服务器宕机等严重问题，那么我们就需要手工进行ACK，保障消费端消费成功！
消费端的重回队列
消费端重回队列是为了对没有处理成功的消息，把消息重新回递给Broker！
一般我们在实际应用中，都会关闭重回队列，也就是设置为False；因为重回队列消息有很大概率依然会处理失败！

Consumer

package com.liuxia.rabbitmqapi.ack;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;


public class Consumer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();


        String exchangeName = "test_ack_exchange";
        String queueName = "test_ack_queue";
        String routingKey = "ack.#";

        channel.exchangeDeclare(exchangeName, "topic", true, false, null);
        channel.queueDeclare(queueName, true, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);

        // 手工签收 必须要关闭 autoAck = false
        channel.basicConsume(queueName, false, new MyConsumer(channel));
    }
}

MyConsumer

package com.liuxia.rabbitmqapi.ack;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

import java.io.IOException;


public class MyConsumer extends DefaultConsumer {


    private Channel channel ;

    public MyConsumer(Channel channel) {
        super(channel);
        this.channel = channel;
    }

    @Override
    public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
        System.err.println("-----------consume message----------");
        System.err.println("body: " + new String(body));
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        if((Integer)properties.getHeaders().get("num") == 0) {
//            手动签收，重回队列
            channel.basicNack(envelope.getDeliveryTag(), false, true);
        } else {
            channel.basicAck(envelope.getDeliveryTag(), false);
        }

    }


}

Producer

package com.liuxia.rabbitmqapi.ack;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

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


public class Producer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();

        String exchange = "test_ack_exchange";
        String routingKey = "ack.save";

        for(int i =0; i<5; i ++){
            Map<String, Object> headers = new HashMap<String, Object>();
            headers.put("num", i);
            AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
                    .deliveryMode(2)
                    .contentEncoding("UTF-8")
                    .headers(headers)
                    .build();
            String msg = "Hello RabbitMQ ACK Message " + i;
            channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
        }
    }
}

我们判断为0的一直重回队列
在这里插入图片描述

TTL消息

TTL是Time To Live的缩写，也就是生存时间
RabbitMQ支持消息的过期时间，在消息发送时可以进行指定
RabbitMQ支持队列的过期时间，从消息入队列开始计算，只要超过了队列的超时时间配置，那么消息自动的清除
纯控制台操作（演示TTL队列消息特点）
针对队列，只要是这个队列的消息，就只有这么长的存活时间

Consumer

package com.liuxia.rabbitmqapi.ttl;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.QueueingConsumer;

import java.util.Map;

public class Consumer {
    public static void main(String[] args) throws Exception {

        //1 创建一个ConnectionFactory, 并进行配置
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        //2 通过连接工厂创建连接
        Connection connection = connectionFactory.newConnection();

        //3 通过connection创建一个Channel
        Channel channel = connection.createChannel();

        //4 声明（创建）一个队列
        String queueName = "test001";
        channel.queueDeclare(queueName, true, false, false, null);

        //5 创建消费者
        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);

        //6 设置Channel
        channel.basicConsume(queueName, true, queueingConsumer);

        while(true){
            //7 获取消息
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String msg = new String(delivery.getBody());
            System.err.println("消费端: " + msg);
            Map<String, Object> headers = delivery.getProperties().getHeaders();
            System.err.println("headers get my1 value: " + headers.get("my1"));

            //Envelope envelope = delivery.getEnvelope();
        }

    }
}

Producer

package com.liuxia.rabbitmqapi.ttl;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

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


public class Procuder {
    public static void main(String[] args) throws Exception {
        //1 创建一个ConnectionFactory, 并进行配置
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        //2 通过连接工厂创建连接
        Connection connection = connectionFactory.newConnection();

        //3 通过connection创建一个Channel
        Channel channel = connection.createChannel();

        Map<String, Object> headers = new HashMap<>();
        headers.put("my1", "111");
        headers.put("my2", "222");


        AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
                .deliveryMode(2)
                .contentEncoding("UTF-8")
                .expiration("10000")
                .headers(headers)
                .build();

        //4 通过Channel发送数据
        for(int i=0; i < 5; i++){
            String msg = "Hello RabbitMQ!";
            //1 exchange   2 routingKey
            channel.basicPublish("", "test001", properties, msg.getBytes());
        }

        //5 记得要关闭相关的连接
        channel.close();
        connection.close();
    }
}

我们去监控平台看，消息在我设置了10秒过后就会消失

死信队列

死信队列：DLX，Dead-Letter-Exchange
利用DLX，当消息在一个队列中变成死信（dead message）之后，它能被重新publish到另一个Exchange，这个Exchange就是DLX
消息变成死信有以下几种情况
消息被拒绝（basic.reject/basic.nack）并且requeue=false
消息TTL过期
队列达到最大长度
死信队列的特点
DLX也是一个正常的Exchange，和一般的Exchange没有区别，它能在任何的队列上被指定，实际上就是设置某个队列的属性；
当这个队列中有死信时，RabbitMQ就会自动的将这个消息重新发布到设置的Exchange上去，进而被路由到另一个队列；
可以监听这个队列中消息做相应的处理，这个特性可以弥补RabbitMQ3.0以前支持的immediate参数的功能；

死信队列设置

首先需要设置死信队列的Exchange和Queue，然后进行绑定：
Exchange：dlx.exchange
Queue：dlx.queue
RoutingKey：#
然后我们进行正常声明交换机、队列、绑定，只不过我们需要在队列加上一个参数即可：
Arguments.put(“x-dead-letter-exchange”,”dlx.exchange”)；
这样消息在过期、requeue、队列在达到最大长度时，消息就可以直接路由到死信队列！

Consumer

package com.liuxia.rabbitmqapi.dlx;

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

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


public class Consumer {
    public static void main(String[] args) throws Exception {


        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();

        // 这就是一个普通的交换机 和 队列 以及路由
        String exchangeName = "test_dlx_exchange";
        String routingKey = "dlx.#";
        String queueName = "test_dlx_queue";

        channel.exchangeDeclare(exchangeName, "topic", true, false, null);

        Map<String, Object> agruments = new HashMap<String, Object>();
        agruments.put("x-dead-letter-exchange", "dlx.exchange");
        //这个agruments属性，要设置到声明队列上
        channel.queueDeclare(queueName, true, false, false, agruments);
        channel.queueBind(queueName, exchangeName, routingKey);

        //要进行死信队列的声明:
        channel.exchangeDeclare("dlx.exchange", "topic", true, false, null);
        channel.queueDeclare("dlx.queue", true, false, false, null);
        channel.queueBind("dlx.queue", "dlx.exchange", "#");

        channel.basicConsume(queueName, true, new MyConsumer(channel));


    }
}

MyConsumer

package com.liuxia.rabbitmqapi.dlx;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

import java.io.IOException;


public class MyConsumer extends DefaultConsumer {


    public MyConsumer(Channel channel) {
        super(channel);
    }

    @Override
    public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
        System.err.println("-----------consume message----------");
        System.err.println("consumerTag: " + consumerTag);
        System.err.println("envelope: " + envelope);
        System.err.println("properties: " + properties);
        System.err.println("body: " + new String(body));
    }


}

Producer


package com.liuxia.rabbitmqapi.dlx;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;


public class Producer {
    public static void main(String[] args) throws Exception {

        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.137.129");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();

        String exchange = "test_dlx_exchange";
        String routingKey = "dlx.save";

        String msg = "Hello RabbitMQ DLX Message";

        for(int i =0; i<1; i ++){

            AMQP.BasicProperties properties = new AMQP.BasicProperties.Builder()
                    .deliveryMode(2)
                    .contentEncoding("UTF-8")
                    .expiration("10000")
                    .build();
            channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
        }

    }
}

在这里插入图片描述
在这里插入图片描述
end…

评论
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付：10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明：

1.余额是钱包充值的虚拟货币，按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载，可以购买VIP、付费专栏及课程。

余额充值