以上图的配置为例，我们以 routingKey="error" 发送消息到 Exchange，则消息会路由到Queue1（amqp.gen-S9b…，这是由RabbitMQ自动生成的Queue名称）和Queue2（amqp.gen-Agl…）。如果我们以 routingKey="info" 或 routingKey="warning" 来发送消息，则消息只会路由到 Queue2。如果我们以其他 routingKey 发送消息，则消息不会路由到这两个 Queue 中。

相对于发布订阅模式，我们可以看到不再是广播似的接收全部消息，而是有选择性的消费。

我们就以接收不同日志级别的队列为例吧。

2. 代码部分

2.1 日志生产者

public class ProdecerRouting {

    private static final String EXCHANGE_NAME = "my_fanout_exchange";

    public static void main(String[] args) throws IOException, TimeoutException {
        /** 1.创建新的连接 */
        Connection connection = MQConnectionUtils.newConnection();
        /** 2.创建通道 */
        Channel channel = connection.createChannel();
        /** 3.绑定的交换机 参数1交互机名称 参数2 exchange类型 */
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        /** 4.发送消息 */
        String message = "",sendType="";
        for (int i = 0; i < 10; i++)
        {
            if(i%2==0){
                sendType = "info";
                message = "我是 info 级别的消息类型：" + i;
            }else{
                sendType = "error";
                message = "我是 error 级别的消息类型：" + i;
            }
            System.out.println("[send]：" + message + "  " +sendType);
            channel.basicPublish(EXCHANGE_NAME, sendType, null, message.getBytes("utf-8"));
            try {
                Thread.sleep(5 * i);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        /** 5.关闭通道、连接 */
        channel.close();
        connection.close();
        /** 注意：如果消费没有绑定交换机和队列，则消息会丢失 */
    }

}

注意：exchangeDeclare() 方法 exchange 类型为 direct

2.2 info消费者

public class ConsumerInfo {

    private static final String QUEUE_NAME = "consumer_info";
    private static final String EXCHANGE_NAME = "my_fanout_exchange";

    public static void main(String[] args) throws IOException, TimeoutException {
        System.out.println("info消费者启动");
        /* 1.创建新的连接 */
        Connection connection = MQConnectionUtils.newConnection();
        /* 2.创建通道 */
        Channel channel = connection.createChannel();
        /* 3.消费者关联队列 */
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        /* 4.消费者绑定交换机 参数1 队列 参数2交换机 参数3 routingKey */
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "info");
        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("消费者获取生产者消息:" + msg);
            }
        };
        /* 5.消费者监听队列消息 */
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

}

2.3 error消费者

public class ConsumerError {

    private static final String QUEUE_NAME = "consumer_error";
    private static final String EXCHANGE_NAME = "my_fanout_exchange";

    public static void main(String[] args) throws IOException, TimeoutException {
        System.out.println("error消费者启动");
        /* 1.创建新的连接 */
        Connection connection = MQConnectionUtils.newConnection();
        /* 2.创建通道 */
        Channel channel = connection.createChannel();
        /* 3.消费者关联队列 */
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        /* 4.消费者绑定交换机 参数1 队列 参数2交换机 参数3 routingKey */
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "error");
        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("消费者获取生产者消息:" + msg);
            }
        };
        /* 5.消费者监听队列消息 */
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

}