work工作消息队列Round-robin与Fair dispatch

一：介绍

1.模型

　　有两种情形，分别是轮训分发与公平分发。

　　

2.出现的场景

　　考虑到simple queue中的缺点。

　　因为生产者发送消息后，消费者消费要花费时间，这个会造成消息的堆积。

二：Round robin--轮循

1.发送程序

　　这个与简单程序类似，只是发送多条数据而已。

package com.mq.work.round;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

public class RoundWorkSend {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args) throws Exception {
        //获取一个连接
        Connection connection= ConnectionUtil.getConnection();
        //从连接中获取一个通道
        Channel channel=connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);

        //消息与发送放入for循环
        for (int i=0;i<50;i++){
            String msg="hello "+i;
            System.out.println("[send msg]:"+msg);
            channel.basicPublish("",QUENE_NAME,null,msg.getBytes());
            Thread.sleep(i*1);
        }

        //关闭连接
        channel.close();
        connection.close();
    }
}

2.消费者一

package com.mq.work.round;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.*;

import java.io.IOException;

public class RoundWorkReceive1 {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args)throws Exception{
        //获取一个连接
        Connection connection = ConnectionUtil.getConnection();
        //创建通道
        Channel channel = connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);
        //创建消费者
        DefaultConsumer consumer=new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg=new String(body,"utf-8");
                System.out.println("[1]receive msg:"+msg);
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    System.out.println("done");
                }
            }
        };
        //监听队列
        boolean autoAck=true;
        channel.basicConsume(QUENE_NAME,autoAck,consumer);
    }
}

3.消费者二

package com.mq.work.round;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.*;

import java.io.IOException;

public class RoundWorkReceive2 {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args)throws Exception{
        //获取一个连接
        Connection connection = ConnectionUtil.getConnection();
        //创建通道
        Channel channel = connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);
        //创建消费者
        DefaultConsumer consumer=new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg=new String(body,"utf-8");
                System.out.println("[2]receive msg:"+msg);
                try {
                    Thread.sleep(300);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    System.out.println("done");
                }
            }
        };
        //监听队列
        boolean autoAck=true;
        channel.basicConsume(QUENE_NAME,autoAck,consumer);
    }
}

4.现象

　　send

　　

　　receive1：

　　

　　receive2：

　　

三：fair dispatcher

1.介绍

　　使用公平分发需要关闭自动应答，改成手动。

　　有一种通俗的说法是：能者多劳。　

2.生产者

　　需要改动的地方是：每个消费者在得到确认消息之前，消息队列不得发送一个消息给消费者，一次只能处理一个消息。

package com.mq.work.fair;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

public class FairWorkSend {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args) throws Exception {
        //获取一个连接
        Connection connection= ConnectionUtil.getConnection();
        //从连接中获取一个通道
        Channel channel=connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);

        //限制发送给一个消费者不得超过1条
        int prefetchCount=1;
        channel.basicQos(prefetchCount);

        //消息与发送放入for循环
        for (int i=0;i<50;i++){
            String msg="hello "+i;
            System.out.println("[send msg]:"+msg);
            channel.basicPublish("",QUENE_NAME,null,msg.getBytes());
            Thread.sleep(i*1);
        }

        //关闭连接
        channel.close();
        connection.close();
    }
}

3.消费者一

　　需要改动的行数,14，18，33,38

package com.mq.work.fair;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.*;

import java.io.IOException;

public class FairWorkReceive1 {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args)throws Exception{
        //获取一个连接
        Connection connection = ConnectionUtil.getConnection();
        //创建通道
        final Channel channel = connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);

        //一次只能发送一个消息
        channel.basicQos(1);

        //创建消费者
        DefaultConsumer consumer=new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg=new String(body,"utf-8");
                System.out.println("[1]receive msg:"+msg);
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    System.out.println("done");
                    //手动应答
                    channel.basicAck(envelope.getDeliveryTag(),false);
                }
            }
        };
        //监听队列,不是自动应答
        boolean autoAck=false;
        channel.basicConsume(QUENE_NAME,autoAck,consumer);
    }
}

3.消费者二

　　与消费者一不同点在于消费每个消息的时间不同。

package com.mq.work.fair;

import com.mq.utils.ConnectionUtil;
import com.rabbitmq.client.*;

import java.io.IOException;

public class FairWorkReceive2 {
    private static final String QUENE_NAME="test_work_queue";
    public static void main(String[] args)throws Exception{
        //获取一个连接
        Connection connection = ConnectionUtil.getConnection();
        //创建通道
        final Channel channel = connection.createChannel();
        //创建队列声明
        channel.queueDeclare(QUENE_NAME,false,false,false,null);

        //一次只能发送一个消息
        channel.basicQos(1);

        //创建消费者
        DefaultConsumer consumer=new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String msg=new String(body,"utf-8");
                System.out.println("[1]receive msg:"+msg);
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }finally {
                    System.out.println("done");
                    //手动应答
                    channel.basicAck(envelope.getDeliveryTag(),false);
                }
            }
        };
        //监听队列,不是自动应答
        boolean autoAck=false;
        channel.basicConsume(QUENE_NAME,autoAck,consumer);
    }
}

4.现象

　　消费者一：

　　

　　消费者二：