RabbitMq七种队列模式应用场景案例分析

参考地址：https://mp.weixin.qq.com/s/HojpU8ICTuXoWNrnIBA_tA

一、简单模式

1、介绍 

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。

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接收人。

2、代码演示

(1)、生产者

public class Sender {

    private final static String QUEUE_NAME = "simple_queue";

    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        // 声明队列
        // 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
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);

        //消息内容
        String message = "simplest mode message";
        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();

    }
｝

（2）、消费者

public class Receiver {

    private final static String QUEUE_NAME = "simplest_queue";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        // 获取连接
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

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

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

二、工作队列模式

1、介绍 

在多个消费者之间分配任务（竞争的消费模式），一个生产者对应多个消费者，一般适用于执行资源密集型任务，单个消费者处理不过来，需要多个消费者进行处理。

用用场景：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处理，这样就是并行了，而不是单个消费者的串行情况。

2、代码演示

（1）、生产者

public class Sender {

    private final static String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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("[x] Sent '" + message + "'");
            Thread.sleep(i * 10);
        }

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

（2）、消费者

C1消费者

public class Receiver1 {

    private final static String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });

    }
}

C2消费者

public class Receiver2 {

    private final static String QUEUE_NAME = "queue_work";

    public static void main(String[] args) throws IOException, InterruptedException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });

    }
}

三、订阅模式

（1）、介绍

一次向许多消费者发送消息，一个生产者发送的消息会被许多消费者获取，也就是消息将广播到所有的消费者中。

应用场景：更新商品库存后需要通知多个缓存和数据库，这里的结构应该是：

（1）、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。

（2）、一个缓存消息队列对应着多个缓存消费者。

（3）、一个数据库消息队列对应着多个数据库消费者。

（2）、代码演示

（1）、生产者

public class Sender {

    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();


        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");

        String message = "publish subscribe message";
        channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));
        System.out.println(" [x] Sent '" + message + "'");

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

（2）、消费者

C1消费者

public class Receive1 {

    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
        };

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

C2消费者

public class Receive2 {

    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received2 '" + message + "'");
        };

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

四、路由模式

 1、介绍

有选择地（Routing key）接收消息，发送消息到交换机并且要指定路由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：如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，只有此促销活动会接收到消息，其他促销活动不关心也不会消费此Routing key的消息。

2、代码演示

（1）、生产者

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, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

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

        // 只有routingKey相同的才会消费
        String message = "routing mode message";
        channel.basicPublish(EXCHANGE_NAME, "key2", null, message.getBytes());
        System.out.println("[x] Sent '" + message + "'");
//        channel.basicPublish(EXCHANGE_NAME, "key", null, message.getBytes());
//        System.out.println("[x] Sent '" + message + "'");

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

（2）、消费者

C1消费者

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, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

C2消费者

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, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });


    }
}

五、主题模式

1、介绍

根据主题（Topic）来接收消息，将路由key和某模式进行匹配，此时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：同上,iPhone促销活动可以接收主题为iPhone的消息，如iPhone12、iPhone13等。

2、代码演示

（1）、生产者

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, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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("[x] Sent '" + message + "'");
        String message2 = "topics model message with key.1.2";
        channel.basicPublish(EXCHANGE_NAME, "key.1.2", null, message2.getBytes());
        System.out.println("[x] Sent '" + message2 + "'");

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

（2）、消费者

C1消费者

public class Receiver1 {

    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 {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

C2消费者

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, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        Connection connection = factory.newConnection();
        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(), "UTF-8");
            System.out.println(" [x] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, true, deliverCallback, consumerTag -> {
        });
    }
}

六、远程过程调用

 1、介绍

如果我们需要在远程计算机上运行功能并等待结果就可以使用RPC，具体流程可以看图。

应用场景：需要等待即可返回数据，如订单支付。

七、发布者确认

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。

八、四种交换机介绍

1、直连交换机（Direct exchange）：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，会将消息发送到对应的队列。

2、扇形交换机（Fanout exchange）：广播消息到所有队列，没有任何处理，速度最快。

3、主题交换机（Topic exchange）：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。

4、首部交换机（Headers exchange）：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。