RabbitMQ的基本概念和七种队列模式

I. RabbitMQ的基本概念

1. 生产者/消费者

• 生产者(Producer)
  消息的创建者。
  负责创建和推送数据到消息服务器。

• 消费者(Consumer)
  消息的接收方。
  负责接收消息和处理数据。

2. 消息队列(Queue)

消息队列是RabbitMQ的内部对象，用于存储生产者的消息直到发送给消费者，它是消费者接收消息的地方。

消息队列的重要属性:

• 持久性
  broker重启前都有效。
• 自动删除
  在所有消费者停止使用之后自动删除。
• 惰性
  没有主动声明队列，调用会导致异常。
• 排他性
  -一旦启用，声明它的消费者才能使用。

3. 交换机(Exchange)

交换机用于接收，分配消息。

1. 生产者要先指定一个routing key，然后将消息发送到交换机。
2. routing key需要与exchange type和binding key联合使用才能最终生效。
3. 交换机将消息路由到一个或多个队列中，或丢弃。

交换机包含4中类型: direct, topic, fanout, headers。

• direct(直连交换机)

具有路由功能的交换机，绑定到此交换机的时候需要指定一个routing_key，交换机发送消息的时候需要routing_key，会将消息发送道对应的队列。

先匹配，再投送。

Direct Exchange是RabbitMQ的默认交换机模式。
这是最简单的模式。
它根据routing key全文匹配去寻找队列。

在绑定队列时会设定一个routing key(通常是队列的名字)。
只有在消息的routing key与队列匹配时，消息才会被交换机投送到绑定的队列中。

---

• topic(主题交换机)

  在直连交换机基础上增加模式匹配，也就是对routing_key进行模式匹配，*代表一个单词，#代表多个单词。

  按规则转发消息。

主题交换机(Topic Exchange)主要根据通配符转发消息。
这种方式最灵活。
交换机和队列的绑定会定义一种路由模式。
路由键(routing key)和路由模式匹配后，交换机才能转发消息。

在这种交换机模式下，路由键(routing key)必须是一串字符，用"."隔开。
路由模式必须包含一个星号"*", 主要用于匹配路由键指定位置的一个单词。
* 匹配一个单词。
# 匹配0个或多个单词。
eg:
binding key:                 *.com.#
匹配的routing key:     cn.com,  us.com.aa
不匹配:                         com.bb

---

• headers(首部交换机)

  忽略routing_key，使用Headers信息(一个Hash的数据结构)进行匹配，优势在于可以有更多更灵活的匹配规则。

  根据应用程序消息的特定属性进行匹配。

---

• fanout(扇形交换机)

  广播消息到所有队列，没有任何处理，速度最快。

  消息广播的模式。

这种方式将消息广播到所有绑定到它的队列中。
不考虑routing key的值，即使配置了路由键，依然会被忽略。

---

4. 消息确认

消息确认是指当一个消息从队列中投递给消费者(consumer)后，消费者会通知一下消息代理(broker)。

消息确认可以自动，也可以由处理消息的开发者手动执行。
当启用消息确认后，消息代理需要收到来自消费者的确认回执后，才完全将消息从队列中删除。

 
 

II. 七种队列模式

1. 简单模式(Hello World)

做最简单的事情，一个生产者对应一个消费者，RabbitMQ相当于一个消息代理，负责将A的消息转发给B。

单生产者，单消费者，单队列。

---

应用场景：

将发送的电子邮件放到消息队列，然后邮件服务在队列中获取邮件并发送给收件人。

2. 工作队列模式(Work queues)

在多个消费者之间分配任务(竞争的消费者模式)，一个生产者对应多个消费者。

适用于资源密集型任务， 单个消费者处理不过来，需要多个消费者进行处理的场景。

单生产者，多消费者，单队列。

---

应用场景：

一个订单的处理需要10s，有多个订单可以同时放到消息队列，

然后让多个消费者同时并行处理，而不是单个消费者的串行消费。

3. 发布订阅模式(Publish/Subscribe)

一次向许多消费者发送消息，将消息将广播到所有的消费者。

单生产者，多消费者，多队列。

应用场景：

更新商品库存后需要通知多个缓存和多个数据库。

结构如下：

• 一个fanout类型交换机扇出两个消息队列，分别为缓存消息队列、数据库消息队列
• 一个缓存消息队列对应着多个缓存消费者
• 一个数据库消息队列对应着多个数据库消费者

4. 路由模式(Routing)

根据Routing Key有选择地接收消息。

多消费者，选择性多队列，每个队列通过routing key全文匹配。

发送消息到交换机并且要指定路由键(Routing key) 。
消费者将队列绑定到交换机时需要指定路由key，仅消费指定路由key的消息。

应用场景：

在商品库存中增加了1台iphone12，iphone12促销活动消费者指定routing key为iphone12 promote，
只有此促销活动会接收到消息，其它促销活动不关心也不会消费此routing key的消息。

5. 主题模式(Topics)

主题交换机方式接收消息，将routing key和模式进行匹配。

多消费者，选择性多队列，每个队列通过模式匹配。

队列需要绑定在一个模式上。
#匹配一个词或多个词，*只匹配一个词。

应用场景：

iphone促销活动可以接收主题为多种iPhone的消息，如iphone12、iphone13等。

6. 远程过程调用(RPC)

在远程计算机上运行功能并等待结果。

应用场景：

需要等待接口返回数据，如订单支付。

7. 发布者确认(Publisher Confirms)

与发布者进行可靠的发布确认，发布者确认是RabbitMQ扩展，可以实现可靠的发布。

在通道上启用发布者确认后，RabbitMQ将异步确认发送者发布的消息，这意味着它们已在服务器端处理。

应用场景：

对于消息可靠性要求较高，比如钱包扣款。

 
 

III. 实战代码

1. 准备工作

首先，我们需要加入rabbitmq的amqp client依赖

<!-- amqp client -->
<dependency>
    <groupId>com.rabbitmq</groupId>
    <artifactId>amqp-client</artifactId>
    <version>5.12.0</version>
</dependency>

其次，我们需要编写一个连接mq和通道的工具类ConnectionUtils，如下:

package com.mcp.lab.mq.rabbit.common.util;

import com.mcp.lab.mq.rabbit.common.domain.ConnInfo;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

public class ConnectionUtils {
    /**
     * 连接器(默认)
     *
     * @return
     * @throws IOException
     * @throws TimeoutException
     */
    public static Connection getConnection() throws IOException, TimeoutException {
        ConnInfo connInfo = new ConnInfo.Builder()
                .setHost("Your RabbitMQ Broker Host")
                .setPort(5672)
                .setVirtualHost("Your Virtual Host(自定义)")
                .setUsername("your rabbit admin user")
                .setPassword("your rabbit admin password")
                .build();

        return getConnection(connInfo);
    }
}

2. 简单模式实例

• 生产者(Producer)代码
  ConsoleSender

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

import java.io.IOException;
import java.util.Scanner;
import java.util.concurrent.TimeoutException;

public class ConsoleSender {
    private static final String QUIT = "Q";
    public static final String QUEUE_NAME = "simple_queue";

    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        // 创建队列声明
        // queue：队列名
        // durable：是否持久化
        // exclusive：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
        // autoDelete：是否自动删除  消费完删除
        // arguments：其他属性
        AMQP.Queue.DeclareOk declareOk = channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        // 输入发送的消息
        Scanner input = new Scanner(System.in);
        String msg = "";
        while (true) {
            System.out.print("请输入发送的消息: ");
            msg = input.nextLine();

            if (QUIT.equals(msg.toUpperCase())) {
                break;
            }

            // exchange，队列，参数，消息字节体
            channel.basicPublish("", QUEUE_NAME, null, msg.getBytes());
            System.out.println("Producer发送的消息: " + msg);
        }

        // 清理工作
        channel.close();
        connection.close();
    }
}

---

• 消费者(Consumer)代码
  SimpleReceiver

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class SimpleReceiver {
    private final static String QUEUE_NAME = "simple_queue";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Consumer] Received from queue - '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

---

运行结果:

1. 首先运行结果生产者(ConsoleSender)
我们在控制台的输入如下:
请输入发送的消息: 789
Producer发送的消息: 789
请输入发送的消息: 111
Producer发送的消息: 111
请输入发送的消息: q

2. 其次运行消费者(SimpleReceiver)
显示如下:
[Consumer] Received from queue - 'simple_queue':'789'
[Consumer] Received from queue - 'simple_queue':'111'

3. 工作队列模式实例

• 生产者(Producer)代码
  WorkQueueSender

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

public class WorkQueueSender {
    private final static String QUEUE_NAME = "work_queue";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

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

---

• 消费者代码(模拟2个消费者)
  WorkQueueReceiver1

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class WorkQueueReceiver1 {
    private final static String QUEUE_NAME = "work_queue";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        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);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Work Consumer 1] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });

    }
}

WorkQueueReceiver2

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class WorkQueueReceiver2 {
    private final static String QUEUE_NAME = "work_queue";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        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);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Work Consumer 2] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });

    }
}

---

运行结果:

1. Producer运行:
[Producer] Sent 'work mode message0'
...
[Producer] Sent 'work mode message99'
---------------------------------------------------

2. Consumer1运行:
 [Work Consumer 1] Received 'work_queue':'work mode message0'
 [Work Consumer 1] Received 'work_queue':'work mode message2'
 ...
 [Work Consumer 1] Received 'work_queue':'work mode message98'
---------------------------------------------------

3. Consumer2运行:
 [Work Consumer 2] Received 'work_queue':'work mode message1'
 [Work Consumer 2] Received 'work_queue':'work mode message3'
 ...
 [Work Consumer 2] Received 'work_queue':'work mode message99'

注: 从上面结果可以看出，2个消费者以抢占的方式消费消息且不重复。

4. 发布订阅模式实例

• 生产者(Producer)代码
  ConsolePublishSender

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

import java.nio.charset.StandardCharsets;
import java.util.Scanner;

public class ConsolePublishSender {
    private static final String QUIT = "Q";
    private static final String EXCHANGE_NAME = "publish_logs";

    public static void main(String[] argv) throws Exception {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");

        // 输入发送的消息
        Scanner input = new Scanner(System.in);
        String msg = "";
        while (true) {
            System.out.print("请输入发送的消息: ");
            msg = input.nextLine();

            if (QUIT.equals(msg.toUpperCase())) {
                break;
            }

            channel.basicPublish(EXCHANGE_NAME, "", null, msg.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [Publisher] Sent '" + msg + "'");
        }

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

---

• 消费者代码(模拟2个消费者)
  SubscribeReceive1

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.nio.charset.StandardCharsets;

public class SubscribeReceive1 {
    private static final String EXCHANGE_NAME = "publish_logs";

    public static void main(String[] argv) throws Exception {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = channel.queueDeclare().getQueue();
        channel.queueBind(queueName, EXCHANGE_NAME, "");

        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        // 订阅消息的回调函数
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Subscriber 1] Received '" + message + "'");
        };

        // 消费者，有消息时触发订阅回调函数
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {
        });
    }
}

SubscribeReceive2

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.nio.charset.StandardCharsets;

public class SubscribeReceive2 {
    private static final String EXCHANGE_NAME = "publish_logs";

    public static void main(String[] argv) throws Exception {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        String queueName = channel.queueDeclare().getQueue();
        channel.queueBind(queueName, EXCHANGE_NAME, "");

        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        // 订阅消息的回调函数
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Subscriber 2] Received '" + message + "'");
        };

        // 消费者，有消息时触发订阅回调函数
        channel.basicConsume(queueName, true, deliverCallback, consumerTag -> {
        });
    }
}

---

运行结果:

1. Producer运行:
请输入发送的消息: topic 1
 [Publisher] Sent 'topic 1'
请输入发送的消息: topic 2
 [Publisher] Sent 'topic 2'
请输入发送的消息: haha
 [Publisher] Sent 'haha'
请输入发送的消息: q
---------------------------------------------------
2. Consumer1运行:
[*] Waiting for messages. To exit press CTRL+C
 [Subscriber 1] Received '发布的主题信息'
 [Subscriber 1] Received 'topic 1'
 [Subscriber 1] Received 'topic 2'
 [Subscriber 1] Received 'haha'
---------------------------------------------------
3. Consumer2运行:
[*] Waiting for messages. To exit press CTRL+C
 [Subscriber 2] Received '发布的主题信息'
 [Subscriber 2] Received 'topic 1'
 [Subscriber 2] Received 'topic 2'
 [Subscriber 2] Received 'haha'

注: 多个接收者接收到一模一样的消息。该模式用于多个消费者订阅同一个主题。

5. 路由模式实例

• 生产者(Producer)代码

ConsoleRouteSender

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

import java.io.IOException;
import java.util.Scanner;
import java.util.concurrent.TimeoutException;

public class ConsoleRouteSender {
    private static final String QUIT = "Q";
    private final static String EXCHANGE_NAME = "exchange_direct";
    private final static String EXCHANGE_TYPE = "direct";

    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        // 交换机声明
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE);

        // 输入发送的消息
        Scanner input = new Scanner(System.in);
        String msg = "";
        while (true) {
            System.out.print("请输入发送的消息: ");
            msg = input.nextLine();

            if (QUIT.equals(msg.toUpperCase())) {
                break;
            }

            // 只有routingKey相同的才会消费
            channel.basicPublish(EXCHANGE_NAME, "key2", null, msg.getBytes());
            //channel.basicPublish(EXCHANGE_NAME, "key", null, msg.getBytes());
            System.out.println("[Route Producer] Sent '" + msg + "'");
        }


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

---

• 消费者代码(模拟2个消费者)

RouteReceiver1

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class RouteReceiver1 {
    private final static String QUEUE_NAME = "queue_routing";
    private final static String EXCHANGE_NAME = "exchange_direct";

    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

        // 指定路由的key，接收key和key2
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key");
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key2");

        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Route Consumer 1] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };

        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

RouteReceiver2

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class RouteReceiver2 {
    private final static String QUEUE_NAME = "queue_routing2";
    private final static String EXCHANGE_NAME = "exchange_direct";

    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

        // 仅接收key2
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key2");

        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Route Consumer 2] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };

        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

---

运行结果:

1. Producer运行:
请输入发送的消息: abc
[Route Producer] Sent 'abc'
请输入发送的消息: test
[Route Producer] Sent 'test'
请输入发送的消息: q
---------------------------------------------------

2. Consumer1运行:
 [Route Consumer 1] Received 'key2':'abc'
[Route Consumer 1] Received 'key2':'test'
---------------------------------------------------

3. Consumer2运行:
[Route Consumer 2] Received 'key2':'abc'
[Route Consumer 2] Received 'key2':'test'

如果把sender中的key2改成key，运行结果如下:

请输入发送的消息: 123
[Route Producer] Sent '123'
请输入发送的消息: 456
[Route Producer] Sent '456'
请输入发送的消息: 789
[Route Producer] Sent '789'
请输入发送的消息: q

[Route Consumer 1] Received 'key':'123'
[Route Consumer 1] Received 'key':'456'
[Route Consumer 1] Received 'key':'789'

consumer2没有数据，因为route key没有匹配。

6. 主题模式实例

• 生产者(Producer)代码

SimpleTopicSender

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

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

    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE);

        String message = "topics model message with key.1";
        channel.basicPublish(EXCHANGE_NAME, "key.1", null, message.getBytes());
        System.out.println("[Producer] Sent '" + message + "'");

        String message2 = "topics model message with key.1.2";
        channel.basicPublish(EXCHANGE_NAME, "key.1.2", null, message2.getBytes());
        System.out.println("[Producer] Sent '" + message2 + "'");

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

---

• 消费者代码(模拟2个消费者)

TopicReceiver1

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class TopicReceiver1 {
    private final static String QUEUE_NAME = "queue_topic";
    private final static String EXCHANGE_NAME = "exchange_topic";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

        // 可以接收key.1
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key.*");

        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Consumer 1] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

TopicReceiver2

import com.mcp.lab.mq.rabbit.common.util.ConnectionUtils;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.DeliverCallback;

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.TimeoutException;

public class TopicReceiver2 {
    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, TimeoutException {
        // 获取一个连接
        Connection connection = ConnectionUtils.getConnection();

        // 从连接获取一个通道
        Channel channel = connection.createChannel();

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

        // *号代表单个单词，可以接收key.1
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "*.*");
        // #号代表多个单词，可以接收key.1.2
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "*.#");

        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), StandardCharsets.UTF_8);
            System.out.println(" [Consumer 2] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

---

运行结果:

1. Producer运行:
[Producer] Sent 'topics model message with key.1'
[Producer] Sent 'topics model message with key.1.2'
---------------------------------------------------

2. Consumer1运行:
 [Consumer 1] Received 'key.1':'topics model message with key.1'
---------------------------------------------------

3. Consumer2运行:
[Consumer 2] Received 'key.1':'topics model message with key.1'
 [Consumer 2] Received 'key.1.2':'topics model message with key.1.2'