RabbitMQ的基礎使用 —— Fanout模式

RabbiteMQ的Fanout模式其實和ActiveMQ的Topic模式比較類似，這裏我們就來看一下見到的小例子吧，首先我們看生成者，這裏生產者和RabbitMQ的基礎使用 —— Direct模式（一）、RabbitMQ的基礎使用 —— Direct模式（二）中的類似，其中最重要的就是需要將交換器的類型修改爲Fanout ，如下：

public class FanoutProducer {

    //交換器名稱
    public static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws Exception {
        //創建連接,連接到RabbitMQ
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        Connection connection = connectionFactory.newConnection();

        //創建信道
        Channel channel = connection.createChannel();
        //創建交換器
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);

        //定義的業務日誌消息級別，即作爲路由鍵使用
        String[] logLevels = {"error", "warn", "info"};
        for (int i = 0; i < logLevels.length; i++) {
            String logLevel = logLevels[i];
            String msg = "Hello RabbitMQ";

            //發佈消息，需要參數：交換器、路由鍵，其中以日誌消息級別爲路由鍵
            channel.basicPublish(EXCHANGE_NAME, logLevel, null, msg.getBytes(Charset.forName("UTF-8")));
        }
        channel.close();
        connection.close();
    }
}

然後我們再來看看消費者端，這裏我們就用兩個消費者來進行測試，一個消費者綁定路由鍵error，另一個消費者這綁定一個不存在的路由鍵other，如下：

public class ErrorConsumer {

    public static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws Exception {
        //創建連接,連接到RabbitMQ,與發送端一樣
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        Connection connection = connectionFactory.newConnection();

        //創建信道
        Channel channel = connection.createChannel();
        //可不創建，由生產者進行創建
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);

        String queueName = "logError";  //聲明一個隊列名稱
        String routingKey = "error";    //路由鍵名稱

        //創建一個隊列
        channel.queueDeclare(queueName, false, false, false, null);
        //將隊列和交換器通過路由鍵進行綁定
        channel.queueBind(queueName, EXCHANGE_NAME, routingKey);

        //聲明瞭一個消費者
        Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                StringBuffer buffer = new StringBuffer();
                buffer.append(Thread.currentThread().getName()).append(", ")
                        .append(envelope.getExchange()).append(", ")
                        .append(envelope.getRoutingKey()).append(", ")
                        .append(new String(body, "UTF-8"));
                System.out.println(buffer.toString());
            }
        };
        //消費者正式開始在指定隊列上消費消息
        channel.basicConsume(queueName, true, consumer);
    }
}

public class OtherConsumer {

    public static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws Exception {
        //創建連接,連接到RabbitMQ,與發送端一樣
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        Connection connection = connectionFactory.newConnection();

        //創建信道
        Channel channel = connection.createChannel();
        //可不創建，由生產者進行創建
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);

        String queueName = "logOther";  //聲明一個隊列名稱
        String routingKey = "other";    //路由鍵名稱

        //創建一個隊列
        channel.queueDeclare(queueName, false, false, false, null);
        //將隊列和交換器通過路由鍵進行綁定
        channel.queueBind(queueName, EXCHANGE_NAME, routingKey);

        //聲明瞭一個消費者
        Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                StringBuffer buffer = new StringBuffer();
                buffer.append(Thread.currentThread().getName()).append(", ")
                        .append(envelope.getExchange()).append(", ")
                        .append(envelope.getRoutingKey()).append(", ")
                        .append(new String(body, "UTF-8"));
                System.out.println(buffer.toString());
            }
        };
        //消費者正式開始在指定隊列上消費消息
        channel.basicConsume(queueName, true, consumer);
    }
}

按我們預期的效果來看，應該不管我們如何調整生產者和消費者的路由鍵，都對消息的接受沒有影響。下面我們進行測試，如下：