Java消息队列RabbitMQ之消息模式详解

2023-07-31 09:48:14 作者：迷鹿小女子

这篇文章主要介绍了Java消息队列RabbitMQ之消息模式详解,RabbitMQ提供了一种qos(服务质量保证)功能,即在非自动确认消息的前提下,如果一定数目的消息(通过基于Consumer或者Channel设置Qos的值)未被确认前,不进行消费新的消息,需要的朋友可以参考下

消费端限流

什么是消费端的限流？

假设一个场景，首先，我们RabbitMQ服务器有上万条未处理的消息，我们随便打开一个消费者客户端，会出现下面情况：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数据！

消费端限流RabbitMQ提供的解决方案

RabbitMQ提供了一种qos（服务质量保证）功能，即在非自动确认消息的前提下，如果一定数目的消息（通过基于Consmer或者Channel设置Qos的值）未被确认前，不进行消费新的消息

Void BasicQos(uint prefetchSize, ushort prefetchCount, bool global);

prefetchSize：0 不限制消息大小

prefetchSize：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Consmer将block（阻塞）掉，直到有消息ack

Global：tre\false是否将上面设置应用于Channel；简单来说，就是上面限制是Channel级别的还是Consmer级

注意：

prefetchSize和global这两项，RabbitMQ没有实现，暂且不研究；

prefetch_cont在no_ask=false的情况下生效，即在自动应答的情况下，这两个值是不生效的；

自定义消费端代码

package com.xieminglu.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);
    }
}

消费端代码

package com.xieminglu.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("192.168.248.134");
        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));
    }
}

提供方代码

package com.xieminglu.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("192.168.248.134");
        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());
        }
    }
}

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！

自定义消费者代码

package com.xieminglu.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);
        }
    }
}

消费者代码

package com.xieminglu.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("192.168.248.134");
        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));
    }
}

生产者代码

package com.xieminglu.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("192.168.248.134");
        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());
        }
    }
}

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

注意：主要针对消息设置，跟交换机、队列、消费者设置毫无关系

消费端代码

package com.xieminglu.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("192.168.248.134");
        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();
        }
    }
}

生产端代码

package com.xieminglu.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("192.168.248.134");
        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();
    }
}

死信队列

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pblish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reqee=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Qee，然后进行绑定：

Exchange：dlx.exchange
Qee：dlx.qee
RotingKey：#

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：

Argments.pt(“x-dead-letter-exchange”,”dlx.exchange”)；

这样消息在过期、reqee、队列在达到最大长度时，消息就可以直接路由到死信队列！

在这里插入图片描述

自定义消费端

package com.xieminglu.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));
    }
}

消费端代码

package com.xieminglu.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("192.168.248.134");
        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));
    }
}

生产端代码

package com.xieminglu.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("192.168.248.134");
        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")//设置过期时间
                    .build();
            channel.basicPublish(exchange, routingKey, true, properties, msg.getBytes());
        }
    }
}

本节学习了RabbitMQ的高级特性，首先介绍了互联网大厂在实际使用中是如何保障100%的消息投递成功和幂等性的，以及对RabbitMQ的确认消息、返回消息、ACK与重回队列、消息的限流，以及对超时时间、死信队列的使用

到此这篇关于Java消息队列RabbitMQ之消息模式详解的文章就介绍到这了,更多相关RabbitMQ之消息模式内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！

Java消息队列RabbitMQ之消息模式详解

消费端限流

消息的ACK与重回队列

消费端手工ACK与NACK

消费端的重回队列

TTL消息

死信队列

消息变成死信有以下几种情况

死信队列设置

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