RabbitMQ 工作队列（轮询和公平）

简单队列的缺点：消费者（Consumer）的消费能力有高有低，当生产者（producer）生产能力远远大于消费者能力，那么消息队列消息就会堆积，最终使消息队列达到上限。

引入工作队列，工作队列包括：轮询和公平两种方式。

★工作队列_轮询

轮询就是增加消费者，每个消费者依次读取消息。

1.创建一个Send.java：

package com.ckfuture.work.rr.send;

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

import java.nio.charset.StandardCharsets;

/**
 * 工作队列-轮询-消息生产者
 */
public class Send {

    //定义队列名称
    private final static String QUEUE_NAME = "work_rr";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        //连接工厂的地址
        factory.setHost("localhost");
        try (
                //连接工厂创建连接
                Connection connection = factory.newConnection();
                //创建信道
                Channel channel = connection.createChannel()) {
            //绑定队列
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            for (int i = 0; i < 20; i++) {
                String message = "Hello World!"+i;
                //发送消息
                channel.basicPublish("", QUEUE_NAME, null, message.getBytes(StandardCharsets.UTF_8));
                System.out.println(" [x] Sent '" + message + "'"+i);
            }           

        }
    }
}

 

 2.创建一个Recv01.java：

package com.ckfuture.work.rr.recv;

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

/**
 * 工作队列-轮询-消息消费者
 */
public class Recv01 {

    private final static String QUEUE_NAME = "work_rr";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //连接工厂创建连接
        Connection connection = factory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //绑定队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            //模拟消费耗时
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
            /**
             * 手动确认
             * multiple:是否确认多条
             */
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false);
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}

3.创建一个Recv02.java:

package com.ckfuture.work.rr.recv;

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

/**
 * 工作队列-轮询-消息消费者
 */
public class Recv02 {

    private final static String QUEUE_NAME = "work_rr";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //连接工厂创建连接
        Connection connection = factory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //绑定队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            //模拟消费耗时
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
            /**
             * 手动确认
             * multiple:是否确认多条
             */
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false);
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}

4.依次运行Recv01和Recv02

 

 5.在管理控制台查看：

 

 

 

 

 

6. 运行Send.java程序

 

 7.可以看到消费者02接收的消息为：

 

 ★工作队列_公平

解决消费者之间消费能力差别的问题，按消费能力分配，能者多劳！！即：利用限流控制只有消费完成才允许获取。

限流代码：

 //限制消费者每次只能接受一条消息，处理完才能接受下一条消息
        int prefetchCount=1;
        channel.basicQos(prefetchCount);

1.创建一个Send.java

package com.ckfuture.work.fair.send;

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

import java.nio.charset.StandardCharsets;

/**
 * 工作队列-公平-消息生产者
 */
public class Send {

    //定义队列名称
    private final static String QUEUE_NAME = "work_fair";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        //连接工厂的地址
        factory.setHost("localhost");
        try (
                //连接工厂创建连接
                Connection connection = factory.newConnection();
                //创建信道
                Channel channel = connection.createChannel()) {
            //绑定队列
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            for (int i = 0; i < 20; i++) {
                String message = "Hello World!"+i;
                //发送消息
                channel.basicPublish("", QUEUE_NAME, null, message.getBytes(StandardCharsets.UTF_8));
                System.out.println(" [x] Sent '" + message + "'"+i);
            }           

        }
    }
}

2.创建Recv01.java:

package com.ckfuture.work.fair.recv;

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

/**
 * 工作队列-公平-消息消费者
 */
public class Recv01 {

    private final static String QUEUE_NAME = "work_fair";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //连接工厂创建连接
        Connection connection = factory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //绑定队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        //限制消费者每次只能接受一条消息，处理完才能接受下一条消息
        int prefetchCount=1;
        channel.basicQos(prefetchCount);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            //模拟消费耗时
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
            /**
             * 手动确认
             * multiple:是否确认多条
             */
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false);
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}

公平模式主要设置：

 

 3.创建Recv02.java

package com.ckfuture.work.fair.recv;

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

/**
 * 工作队列-公平-消息消费者
 */
public class Recv02 {

    private final static String QUEUE_NAME = "work_fair";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //连接工厂创建连接
        Connection connection = factory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //绑定队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        //限制消费者每次只能接受一条消息，处理完才能接受下一条消息
        int prefetchCount=1;
        channel.basicQos(prefetchCount);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            //模拟消费耗时
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
            /**
             * 手动确认
             * multiple:是否确认多条
             */
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(),false);
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}

4.依次运行Recv01、Recv02、Send三个程序

Recv01消费能力强消费的多

 

 Recv02消费能力弱