RabbitMQ之消息模式(一)

文章目錄

消息100%的投遞

消息如何保障100%的投遞成功？
什麼是生產端的可靠性投遞？

保障消息的成功發出
保障MQ節點的成功接收
發送端收到MQ節點（Broker）確認應答
完善的消息進行補償機制

BAT/TMD互聯網大廠的解決方案：

消息落庫，對消息狀態進行打標
消息的延遲投遞，做二次確認，回調檢查

冪等性概念

冪等性是什麼？

我們可以借鑑數據庫的樂觀鎖機制
比如我們執行一條更新庫存的SQL語句
Update t_repository set count = count -1,version = version + 1 where version = 1
Elasticsearch也是嚴格遵循冪等性概念，每次數據更新，version+1（博主博客前面有提到）

消費端-冪等性保障
在海量訂單產生的業務高峯期，如何避免消息的重複消費問題？
消費實現冪等性，就意味着，我們的消息永遠不會消費多次，即使我們收到了多條一樣的消息

業界主流的冪等性操作
唯一ID+指紋碼機制，利用數據庫主鍵去重
利用Redis的原子性去實現

唯一ID+指紋碼機制
唯一ID+指紋碼機制，利用數據庫主鍵去重
Select count(1) from T_order where ID=唯一ID+指紋碼
好處：實現簡單
壞處：高併發下有數據庫寫入的性能瓶頸
解決方案：根據ID進行分庫分表進行算法路由

利用Redis的原子性去實現
使用Redis進行冪等，需要考慮的問題
第一：我們是否要進行數據落庫，如果落庫的話，關鍵解決的問題是數據庫和緩存如何做到原子性？
第二：如果不進行落庫，那麼都存儲到緩存中，如何設置定時同步策略？

Confirm確認消息

理解Confirm消息確認機制
消息的確認，是指生產者投遞消息後，如果Broker收到消息，則會給我們生產者一個應答。
生產者進行接收應答，用來確定這條消息是否正常的發送到Broker，這種方式也是消息的可靠性投遞的核心保障

如何實現Confirm確認消息？
第一步：在Channel上開啓確認模式：channel.confirmSelect()
第二步：在channel上添加監聽：addConfirmListener，監聽成功和失敗的返回結果，根據具體的結果對消息進行重新發送、或記錄日誌等後續處理！

消費端代碼:

package com.zh.rabbitmqapi.confirm;

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

public class Consumer {
    public static void main(String[] args) throws Exception {
        //1 創建ConnectionFactory
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        //2 獲取C    onnection
        Connection connection = connectionFactory.newConnection();

        //3 通過Connection創建一個新的Channel
        Channel channel = connection.createChannel();

        String exchangeName = "test_confirm_exchange";
        String routingKey = "confirm.#";
        String queueName = "test_confirm_queue";

        //4 聲明交換機和隊列 然後進行綁定設置, 最後制定路由Key
        channel.exchangeDeclare(exchangeName, "topic", true);
        channel.queueDeclare(queueName, true, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);

        //5 創建消費者
        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);
        channel.basicConsume(queueName, true, queueingConsumer);

        while(true){
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String msg = new String(delivery.getBody());

            System.err.println("消費端: " + msg);
        }


    }
}

服務提供方代碼:

package com.zh.rabbitmqapi.confirm;

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

import java.io.IOException;

public class Producer {
    public static void main(String[] args) throws Exception {
        //1 創建ConnectionFactory
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

        //2 獲取C    onnection
        Connection connection = connectionFactory.newConnection();

        //3 通過Connection創建一個新的Channel
        Channel channel = connection.createChannel();


        //4 指定我們的消息投遞模式: 消息的確認模式
        channel.confirmSelect();

        String exchangeName = "test_confirm_exchange";
        String routingKey = "confirm.save";

        //5 發送一條消息
        String msg = "Hello RabbitMQ Send confirm message!";
        channel.basicPublish(exchangeName, routingKey, null, msg.getBytes());

        //6 添加一個確認監聽
        channel.addConfirmListener(new ConfirmListener() {
            @Override
            public void handleNack(long deliveryTag, boolean multiple) throws IOException {
                System.err.println("-------no ack!-----------");
            }

            @Override
            public void handleAck(long deliveryTag, boolean multiple) throws IOException {
                System.err.println("-------ack!-----------");
            }
        });
    }
}

Return返回消息

Return Listener用於處理一些不可路由的消息！
正常情況：我們的消息生產者，通過指定一個Exchange和RoutingKey，把消息送達到某一個隊列中去，然後我們的消費者監聽隊列，進行消費處理操作！
異常情況：在某些情況下，如果我們在發送消息的時候，當前的Exchange不存在或者指定的路由key路由不到，這個時候如果我們需要監聽這種不可達的消息，就需要使用Return Listener！

在基礎API中有一個關鍵的配置項
Mandatory：如果爲true，則監聽器會接收到路由不可達的消息，然後進行後續處理，如果爲false，那麼Broker端自動刪除該消息！

消費端代碼:

package com.zh.rabbitmqapi.returnlistener;

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

public class Consumer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

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

        String exchangeName = "test_return_exchange";
        String routingKey = "return.#";
        String queueName = "test_return_queue";

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

        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);

        channel.basicConsume(queueName, true, queueingConsumer);

        while(true){
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String msg = new String(delivery.getBody());
            System.err.println("消費者: " + msg);
        }

    }
}

生產端代碼:

package com.zh.rabbitmqapi.returnlistener;

import com.rabbitmq.client.*;

import java.io.IOException;

public class Producer {
    public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

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

        String exchange = "test_return_exchange";
        String routingKey = "return.save";
        String routingKeyError = "abc.save";

        String msg = "Hello RabbitMQ Return Message";


        channel.addReturnListener(new ReturnListener() {
            @Override
            public void handleReturn(int replyCode, String replyText, String exchange,
                                     String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {

                System.err.println("---------handle  return----------");
                System.err.println("replyCode: " + replyCode);
                System.err.println("replyText: " + replyText);
                System.err.println("exchange: " + exchange);
                System.err.println("routingKey: " + routingKey);
                System.err.println("properties: " + properties);
                System.err.println("body: " + new String(body));
            }
        });

        //消息投遞成功，會被消費者所消費
//        channel.basicPublish(exchange, routingKey, true, null, msg.getBytes());
        //消息不可達，將觸發ReturnListener
         channel.basicPublish(exchange, routingKeyError, true, null, msg.getBytes());
    }
}

投遞不成功:

消息投遞成功:

自定義消費者

我們一般就是在代碼中編寫while循環，進行consumer.nextDelivery方法進行獲取下一條消息，然後進行消費處理！
但是我們使用自定義的Consumer更加的方便，解耦性更加的強，也是實際工作中最常用的使用方式！

自定義消費端代碼

package com.zh.rabbitmqapi.consumer;

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));
    }
}

消費端調用:

package com.zh.rabbitmqapi.consumer;

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("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

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


        String exchangeName = "test_consumer_exchange";
        String routingKey = "consumer.#";
        String queueName = "test_consumer_queue";

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

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


    }
}

生產端調用:

package com.zh.rabbitmqapi.consumer;

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("192.168.43.35");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");

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

        String exchange = "test_consumer_exchange";
        String routingKey = "consumer.save";

        String msg = "Hello RabbitMQ Consumer Message";

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

    }
}

RabbitMQ之消息模式(一)

文章目錄

消息100%的投遞

冪等性概念

Confirm確認消息

Return返回消息

自定義消費者

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