5、RabbitMQ学习笔记—Exchange交换机

Exchange交换机

接收消息，并根据路由键转发消息所绑定的队列

这是官网的一个交换机模型图，其中：

• 蓝色框：表示客户端（client）发送消息到交换机（exchange）并通过一定路由规则（routingkey）进行转发到消息队列（queue）中。
• 绿色框：表示消息消费者从队列（queue）中获取消息进行处理消费。
• 红色框：表示rabbitmq服务包含的内容
• 黄色框：交换机和消息队列之间的绑定关系（routingkey）

属性

• name 交换机名称
• type 交换机类型 direct、topic、fanout、headers
• durability 是否需要持久化，boolen值
• autodelete 当最后一个绑定到exchange上的队列删除后，自动删除该exchange
• internal 当前exchange是否用于rabbitmq内部使用，默认false
• arguments 扩展参数，用于扩展AMQP协议自制定化使用

交换机类型

1、direct
所有发送到direct exchange的消息被转发到routingkey中指定的queue

注意
direct模式可以使用rabbitmq自带的exchange：default exchange，所以不需要将exchange进行任何的绑定（binding）操作，消息传递时，routingkey必须完全匹配才会被队列接受，否则该消息会被抛弃。

生产者

 public static final String EXCHANGE_NAME = "test_exchange_direct";
    public static final String ROUTING_KEY = "routingkey.direct";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 发送消息
        String message = "test message for exchange_direct";
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY, null, message.getBytes());
        System.out.println("发送成功：" + message);
        channel.close();
        connection.close();
    }

消费者

public static final String EXCHANGE_NAME = "test_exchange_direct";
    public static final String EXCHANGE_TYPE = "direct";
    public static final String ROUTING_KEY = "routingkey.direct";
    public static final String QUEUE_NAME = "test_queue";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

首先运行消费者，启动监听。再运行生产者，此时查看消费者控制台，可看到已接收到消息

如果修改其中任一的routingkey，使得两者routingkey不一致，那么再次执行上述步骤，消费者则无法接受到消息。
2、topic
所有发送到topic exchange的消息被转发到所有关心routingkey中指定topic的queue上
exchange将routingkey 和某个topic进行模糊匹配，此时队列需要绑定一个topic

可以使用通配符

创建生产者

    public static final String EXCHANGE_NAME = "test_exchange_topic";
    public static final String ROUTING_KEY1 = "routingkey.topic";
    public static final String ROUTING_KEY2 = "routingkey.topic.a";
    public static final String ROUTING_KEY3 = "routingkey2.topic";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 发送消息
        String message1 = "test message for exchange_topic 1";
        String message2 = "test message for exchange_topic 2";
        String message3 = "test message for exchange_topic 3";
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY1, null, message1.getBytes());
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY2, null, message2.getBytes());
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY3, null, message3.getBytes());
        System.out.println("发送成功");
        channel.close();
        connection.close();
    }

创建三个消费者,分别使用不同的routingkey

// 消费者1 接受消息1和消息2
public static final String EXCHANGE_NAME = "test_exchange_topic";
    public static final String EXCHANGE_TYPE = "topic";
    public static final String ROUTING_KEY = "routingkey.#";
    public static final String QUEUE_NAME = "test_queue1";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

// 消费者2 接受消息1
    public static final String EXCHANGE_NAME = "test_exchange_topic";
    public static final String EXCHANGE_TYPE = "topic";
    public static final String ROUTING_KEY = "routingkey.*";
    public static final String QUEUE_NAME = "test_queue2";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

// 消费者3 接受消息1和消息3
public static final String EXCHANGE_NAME = "test_exchange_topic";
    public static final String EXCHANGE_TYPE = "topic";
    public static final String ROUTING_KEY = "*.topic";
    public static final String QUEUE_NAME = "test_queue3";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

我们分别启动三个消费者，然后启动生产者后，查看三个消费者的控制台输出



3、fanout
不处理任何路由键，只需要简单的将队列绑定到交换机上
发送到交换机的消息都会被转发到与该交换机绑定的所有队列上
fanout交换机转发消息的效率是最快的

生产者

public static final String EXCHANGE_NAME = "test_exchange_fanout";
    public static final String ROUTING_KEY1 = "routingkey.fanout";
    public static final String ROUTING_KEY2 = "routingkey.fanout.a";
    public static final String ROUTING_KEY3 = "routingkey2.fanout";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 发送消息
        String message1 = "test message for exchange_fanout 1";
        String message2 = "test message for exchange_fanout 2";
        String message3 = "test message for exchange_fanout 3";
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY1, null, message1.getBytes());
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY2, null, message2.getBytes());
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY3, null, message3.getBytes());
        System.out.println("发送成功");
        channel.close();
        connection.close();
    }

消费者1

public static final String EXCHANGE_NAME = "test_exchange_fanout";
    public static final String EXCHANGE_TYPE = "fanout";
    public static final String ROUTING_KEY = "routingkey.#";
    public static final String QUEUE_NAME = "test_queue1";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

消费者2

public static final String EXCHANGE_NAME = "test_exchange_fanout";
    public static final String EXCHANGE_TYPE = "fanout";
    public static final String ROUTING_KEY = "routingkey.*";
    public static final String QUEUE_NAME = "test_queue2";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

消费者3

public static final String EXCHANGE_NAME = "test_exchange_fanout";
    public static final String EXCHANGE_TYPE = "fanout";
    public static final String ROUTING_KEY = "*.fanout";
    public static final String QUEUE_NAME = "test_queue3";
    public static void main(String[] args) throws IOException, TimeoutException {
        // 获取连接
        Connection connection = ConnectionsUtils.getConnection();
        // 创建信道
        Channel channel = connection.createChannel();
        // 声明交换机
        channel.exchangeDeclare(EXCHANGE_NAME, EXCHANGE_TYPE, true, false, false ,null);
        // 声明队列
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        // 绑定
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);
        // 创建消费者进行监听获取消息
        DefaultConsumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("接收消息message: " + new String(body));
                System.out.println("consumerTag: " + consumerTag);
                System.out.println("envelope: " + envelope);
                System.out.println("properties: " + properties);
            }
        };
        channel.basicConsume(QUEUE_NAME, true, consumer);
    }

因为fanout模式不会处理任何的路由键，因此，这里我们将exchange模式设置为fanout后，无论设置routing可以与否，都会将消息发送到每个绑定该exchange的队列上去，因此，三个消费者都会接收到三条消息