RabbitMq七种工作模式，结合简单的java实例使用，别再说你不会

2020-08-01

一、Maven依赖添加

 <!-- rabbitmq相关依赖 -->
        <dependency>
            <groupId>com.rabbitmq</groupId>
            <artifactId>amqp-client</artifactId>
            <version>3.0.4</version>
        </dependency>

二、七种工作模式的JAVA实例

1、简单模式

最简单的一个消费者和一个生产者模式，生产者生成消息，消费者监听消息，若是消费者监听到它所需要的消息，就会消费该消息，这种消息是次性的，被消费了就没有了。

1.1.1、EasyRecv.java

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

public class EasyRecv {
    //队列名称
    private final static String QUEUE_NAME = "hello world";
    public static void main(String[] argv) throws java.io.IOException,java.lang.InterruptedException {
        //打开连接和创建频道，与发送端一样
        ConnectionFactory factory = new ConnectionFactory();
        //设置RabbitMQ所在主机ip或者主机名
        factory.setHost("127.0.0.1");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        //声明队列，主要为了防止消息接收者先运行此程序，队列还不存在时创建队列。
               /**
         * 队列名
         * 是否持久化
         *  是否排外  即只允许该channel访问该队列   一般等于true的话用于一个队列只能有一个消费者来消费的场景
         *  是否自动删除  消费完删除
         *  其他属性
         *
         */
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        System.out.println("Waiting for messages. To exit press CTRL+C");

        //创建队列消费者
        QueueingConsumer consumer = new QueueingConsumer(channel);
        //指定消费队列
         /**
         * 队列名
         * 其他属性  路由
         * 消息body
         */
        channel.basicConsume(QUEUE_NAME, true, consumer);
        while (true)
        {
            //nextDelivery是一个阻塞方法（内部实现其实是阻塞队列的take方法）
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("Received '" + message + "'");
        }

    }
}

1.1.2、EasySend.java

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

import java.util.Scanner;

public class EasySend {

    //队列名称
    private final static String QUEUE_NAME = "hello world";

    public static void main(String[] argv) throws java.io.IOException
    {
        /**
         * 创建连接连接到MabbitMQ
         */
        ConnectionFactory factory = new ConnectionFactory();
        //设置MabbitMQ所在主机ip或者主机名
        factory.setHost("127.0.0.1");


        while (true){
            //创建一个连接
            Connection connection = factory.newConnection();
            //创建一个频道
            Channel channel = connection.createChannel();
            //指定一个队列
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            //发送的消息
            Scanner scanner = new Scanner(System.in);
            String ms = scanner.nextLine();
            //String message = "hello world!";
            //往队列中发出一条消息
            channel.basicPublish("", QUEUE_NAME, null, ms.getBytes());
            System.out.println("Sent '" + ms + "'");
            //关闭频道和连接
            channel.close();
            connection.close();
        }
    }

以上两个已经可以进行通信了，下面同样是简单的实例，但是我们可以看到在代码层面上，连接的代码都是一样的，所以我们可以创建一个连接的工具类。

1.2.1、RabbitmqConnectionUtil .java

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

import java.io.IOException;


public  class RabbitmqConnectionUtil {

    public static Connection getConnection() throws IOException {
        //连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //连接5672端口  注意15672为工具界面端口  25672为集群端口
        factory.setPort(5672);
        //factory.setVirtualHost("/xxxxx");
       // factory.setUsername("xxxxxx");
       // factory.setPassword("123456");
        //获取连接
        Connection connection = factory.newConnection();
        return connection;
    }
}

1.2.2、UtilSend.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class UtilSend {
    private final static String QUEUE_NAME = "UtilConn";
    public static void main(String[] args) throws IOException {

        Connection connection = RabbitmqConnectionUtil.getConnection();
        //创建通道
        Channel channel = connection.createChannel();
        //声明队列
 
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        //消息内容
  
        String message = "这里是lbw广场";
        channel.basicPublish("", QUEUE_NAME,null,message.getBytes());
        System.out.println("[x]Sent '"+message + "'");
        //最后关闭通关和连接
        channel.close();
        connection.close();
    }
}

1.2.3、UtilRecv.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.QueueingConsumer;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class UtilRecv {
    private final static String QUEUE_NAME = "UtilConn";
    public static void main(String[] args) throws IOException, InterruptedException {

        Connection connection = null;
        connection = RabbitmqConnectionUtil.getConnection();
        //创建通道
        Channel channel = connection.createChannel();
        //声明队列
       
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);

        channel.basicConsume(QUEUE_NAME,true,queueingConsumer);

        while(true){
            //该方法会阻塞
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received '"+message+"'");
        }

    }
}

2、工作队列

工作队列也就是简单模式的强化版，一个队列是可以多个生产者，也可以有多个消费者来竞争消费消息，但是我们仍需保证队列的幂等性，队列存在就不能再创建同名队列。

下面的每个进程都控制其主线程休眠，让我们可以更好的看到结果。

2.1.1、Sender1.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Sender1 {
    private final  static String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        for(int i = 0; i < 100; i++){
            String message = "lbw" + i;
            channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
            System.out.println("[x] Sent '"+message + "'");
            Thread.sleep(i*10);
        }

        channel.close();
        connection.close();
    }
}

2.1.2、Sender2.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Sender2 {
    private final  static String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        for(int i = 0; i < 100; i++){
            String message = "nb" + i;
            channel.basicPublish("", QUEUE_NAME, null, message.getBytes());
            System.out.println("[x] Sent '"+message + "'");
            Thread.sleep(i*10);
        }
        channel.close();
        connection.close();
    }
}

2.1.3、Receiver1.java

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

import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

/**
 * Created by san
 */
public class Receiver1 {
    private final static  String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false,false, false,null);
        //同一时刻服务器只会发送一条消息给消费者
        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        //关于手工确认 待之后有时间研究下
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received1 '"+message+"'");
            Thread.sleep(10);
            //返回确认状态
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }

    }
}

2.1.4、Receiver2.java

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

import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

/**
 * Created by san
 */
public class Receiver2 {
    private final static  String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException {

        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false,false, false,null);
        //同一时刻服务器只会发送一条消息给消费者
        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        
        
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received2 '"+message+"'");
            Thread.sleep(1000);
            //返回确认状态
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }

    }
}

2.1.5、结果

上面的四个程序都运行起来，结果可以看到如下，依据结果分析，可知，同一个消息队列，是可以有多个生产者和消费者的。

3、发布/订阅（fanout）

3.1.1、Sender.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

public class Sender {
    private final static String EXCHANGE_NAME = "test_exchange_fanout";

    public static void main(String[] args)
    {
        try
        {
            //获取连接
            Connection connection = RabbitmqConnectionUtil.getConnection();
            //从连接中获取一个通道
            Channel channel = connection.createChannel();
            //声明交换机（分发:发布/订阅模式）
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            //发送消息
            for (int i = 0; i < 5; i++)
            {
                String message = "卢本伟广场" + i;
                System.out.println("[send]：" + message);
                //发送消息
                channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("utf-8"));
                Thread.sleep(5 * i);
            }
            channel.close();
            connection.close();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

}

3.1.2、Receiver1.java

import com.rabbitmq.client.*;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Receiver1 {
    //交换机名称
    private final static String EXCHANGE_NAME = "test_exchange_fanout";

    //队列名称
    private static final String QUEUE_NAME    = "test_queue_email";

    public static void main(String[] args)
    {
        try
        {
            //获取连接
            Connection connection = RabbitmqConnectionUtil.getConnection();
            //从连接中获取一个通道
            final Channel channel = connection.createChannel();
            //声明交换机（分发:发布/订阅模式）
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            //声明队列
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            //将队列绑定到交换机
            channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "");
            //保证一次只分发一个
            int prefetchCount = 1;
            channel.basicQos(prefetchCount);
            //定义消费者
            DefaultConsumer consumer = new DefaultConsumer(channel)
            {
                //当消息到达时执行回调方法
                @Override
                public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
                                           byte[] body) throws IOException
                {
                    String message = new String(body, "utf-8");
                    System.out.println("[email] Receive message：" + message);
                    try
                    {
                        //消费者休息2s处理业务
                        Thread.sleep(1000);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                    finally
                    {
                        System.out.println("[1] done");
                        //手动应答
                        channel.basicAck(envelope.getDeliveryTag(), false);
                    }
                }
            };
            //设置手动应答
            boolean autoAck = false;
            //监听队列
            channel.basicConsume(QUEUE_NAME, autoAck, consumer);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

3.1.3、Receiver2.java

import com.rabbitmq.client.*;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Receiver2 {

    //交换机名称
    private final static String EXCHANGE_NAME = "test_exchange_fanout";

    //队列名称
    private static final String QUEUE_NAME    = "test_queue_phone";

    public static void main(String[] args)
    {
        try
        {

            //获取连接
            Connection connection = RabbitmqConnectionUtil.getConnection();
            //从连接中获取一个通道
            final Channel channel = connection.createChannel();
            //声明交换机（分发:发布/订阅模式）
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            //声明队列
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);
            //将队列绑定到交换机
            channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "");
            //保证一次只分发一个
            int prefetchCount = 1;
            channel.basicQos(prefetchCount);
            //定义消费者
            DefaultConsumer consumer = new DefaultConsumer(channel)
            {
                //当消息到达时执行回调方法
                @Override
                public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
                                           byte[] body) throws IOException
                {
                    String message = new String(body, "utf-8");
                    System.out.println("[phone] Receive message：" + message);
                    try
                    {
                        //消费者休息1s处理业务
                        Thread.sleep(1000);
                    }
                    catch (InterruptedException e)
                    {
                        e.printStackTrace();
                    }
                    finally
                    {
                        System.out.println("[2] done");
                        //手动应答
                        channel.basicAck(envelope.getDeliveryTag(), false);
                    }
                }
            };
            //设置手动应答
            boolean autoAck = false;
            //监听队列
            channel.basicConsume(QUEUE_NAME, autoAck, consumer);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

3.1.4、结果

从程序运行结果和RabbitMq的后台看出，这样的消息属于广播型，两个不同名的队列的都能收到该消息，只需它们都将自己绑定到同一个交换机,而且，该消息是持久的，只要交换机还在，消费者啥时候上线都能消费它所绑定的交换机，而且只会一个消费者只会消费一

4、路由（direct）

在前面的示例中，我们已经在创建绑定。您可能会想起类似的代码：

channel.queueBind（queueName，EXCHANGE_NAME，“”）;

绑定是交换和队列之间的关系。可以简单地理解为：队列对来自此交换的消息感兴趣。

绑定可以采用额外的routingKey参数。为了避免与basic_publish参数混淆，我们将其称为绑定键。这是我们可以创建带有键的绑定的方法：

channel.queueBind（queueName，EXCHANGE_NAME，“ black”）;

直接绑定(密钥直接绑定到单个队列)

多重绑定（相同的绑定密钥绑定多个队列）

不同密钥绑定不同的队列，可以发挥出不同日志级别发送到不同的队列的效果。

4.1.1、Sender

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;


public class Sender {
    private final static String EXCHANGE_NAME = "exchange_direct";
    private final static String EXCHANGE_TYPE = "direct";

    public static void main(String[] args) throws IOException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME,EXCHANGE_TYPE);

        String message = "那一定是蓝色";
        channel.basicPublish(EXCHANGE_NAME,"key2", null, message.getBytes());
        System.out.println("[x] Sent '"+message+"'");

        channel.close();
        connection.close();
    }
}

4.1.2、Receiver1.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.QueueingConsumer;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

/**
 * Created by san
 */
public class Receiver1 {
    private final  static  String QUEUE_NAME = "queue_routing";
    private final static String EXCHANGE_NAME = "exchange_direct";

    public static void main(String[] args) throws IOException, InterruptedException {
        // 获取到连接以及mq通道
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false,false,false,null);
        channel.queueBind(QUEUE_NAME,EXCHANGE_NAME,"key");
        channel.queueBind(QUEUE_NAME,EXCHANGE_NAME,"key2");

        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received1 "+message);
            Thread.sleep(10);

            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }


    }
}

4.1.3、Receiver2.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.QueueingConsumer;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;
import java.io.IOException;

/**
 * Created by san
 */
public class Receiver2 {
    private final  static  String QUEUE_NAME = "queue_routing2";
    private final static String EXCHANGE_NAME = "exchange_direct";

    public static void main(String[] args) throws IOException, InterruptedException {
        // 获取到连接以及mq通道
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false,false,false,null);
        channel.queueBind(QUEUE_NAME,EXCHANGE_NAME,"key2");

        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received2 "+message);
            Thread.sleep(10);

            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }
    }
}

4.1.4、结果-总结

有一点要注意是：在direct下，必须是Exchange（交换机）已经存在，消费端的队列才能绑定到Exchange，否则会报错。也就说上面的程序第一次运行时，需先启Sender，才能成功启动Reciver。

5、话题（topic）

话题也是一个持久的消息，只要交换机还在，每个上线的消费者都可以消费一次自己感兴趣的topic。

*（星号）可以代替一个单词。
＃（哈希）可以替代零个或多个单词。

5.1.1、Sender.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Sender {
    private final static String EXCHANGE_NAME = "exchange_topic";
    private final static String EXCHANGE_TYPE = "topic";

    public static void main(String[] args) throws IOException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE);

        //消息内容
        String message = "这里是卢本伟广场";
        //第二个参数是topic匹配值
        channel.basicPublish(EXCHANGE_NAME,"lbw.nb",null,message.getBytes());
        System.out.println("[x] Sent '"+message+"'");

        //关通道 关连接
        channel.close();
        connection.close();
    }
}

5.1.2、Receiver1.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.QueueingConsumer;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Receiver1 {
    private final static String QUEUE_NAME = "queue_topic";
    private final static String EXCHANGE_NAME = "exchange_topic";
    private final static String EXCHANGE_TYPE = "topic";

    public static void main(String[] args) throws IOException, InterruptedException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false, false,false, null);
        //第二参数就是去匹配我兴趣的topic
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "lbw.nb.*");

        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received1 '"+message + "'");
            Thread.sleep(10);
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);

        }
    }
}

5.1.3、Receiver2.java

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.QueueingConsumer;
import top.san.RabbitMq.util.RabbitmqConnectionUtil;

import java.io.IOException;

public class Receiver2 {

    private final static String QUEUE_NAME = "queue_topic2";
    private final static String EXCHANGE_NAME = "exchange_topic";
    private final static String EXCHANGE_TYPE = "topic";

    public static void main(String[] args) throws IOException, InterruptedException {
        Connection connection = RabbitmqConnectionUtil.getConnection();
        Channel channel = connection.createChannel();

        channel.queueDeclare(QUEUE_NAME, false, false,false, null);

        //第二参数就是去匹配我兴趣的topic
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "lbw.#");

        channel.basicQos(1);

        QueueingConsumer consumer = new QueueingConsumer(channel);
        channel.basicConsume(QUEUE_NAME, false, consumer);

        while(true){
            QueueingConsumer.Delivery delivery = consumer.nextDelivery();
            String message = new String(delivery.getBody());
            System.out.println("[x] Received2 '"+message + "'");
            Thread.sleep(10);

            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
        }
    }
}

5.1.4、结果-分析

话题的特色就是队列可以获取自己感兴趣的话题消息，可以通过通配符*或#来表示匹配所有的感兴趣的字符串。

6、RPC（远程过程调用）

给张图自己体会吧（官网没给示例代码，我也就不写了），就是通过两个交换机实现一个可回调的过程吧。

三、RabbitMq的交换机

RabbitMq是有一个交换机的概念的，消息(Message)由Client发送，RabbitMQ接收到消息之后通过交换机转发到对应的队列上面。Worker会从队列中获取未被读取的数据处理。这样就可以实现消息的发送者无需知道消息使用者的存在，反之亦然。Direct exchange：直连（路由）交换机，转发消息到routigKey指定的队列

Fanout exchange：扇形交换机，转发消息到所有绑定队列（相当于广播）

Topic exchange：主题交换机，按规则转发消息（很灵活）

Headers exchange：首部交换机

前面的简单类型我们都是忽略了交换机的参数的，如该方法：channel.basicPublish("", QUEUE_NAME, null, message.getBytes());就是这个方法的第一个参数，置空说明使用了默认的交换机。
有几种交换类型可用：direct，topic，headers 和fanout。

作者：小小卡尔

原文链接：https://blog.csdn.net/weixin_44185736/article/details/106574637