RabbitMQ之交换机

≡放荡痞女 提交于 2020-12-16 21:11:07

1. 交换机类型

  rabbitmq常见有四种交换机类型: direct, topic, fanout, headers.

  一般headers都不用,工作中用得较多的是fanout,它会将消息推送到所有绑定在此交换机上的队列中,效率也是这几种交换机中最高的。

  交换机是啥? 感觉跟网关差不多,就是路由、转发消息.

  下面具体说说几种交换机的使用

 

2. 交换机的使用

2.1 direct 交换机

  direct: 直连   相当于 1 对 1.  

  生产者----> direct exchange ---> queue ----> 消费者

  

// 生产端代码
public static void main(String[] args) throws Exception {
        
        //1 创建ConnectionFactory
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        //2 创建Connection
        Connection connection = connectionFactory.newConnection();
        //3 创建Channel
        Channel channel = connection.createChannel();  
        //4 声明
        String exchangeName = "direct_exchange";
                // 5. 路由key, 消费端必须与其一致
        String routingKey = "direct.routingKey";
        //5 发送
        
        String msg = "this is direct exchange test... ";
        channel.basicPublish(exchangeName, routingKey , null , msg.getBytes());         
        
    }

 

// 消费端代码
public static void main(String[] args) throws Exception {
        ConnectionFactory connectionFactory = new ConnectionFactory() ;  
        
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        connectionFactory.setAutomaticRecoveryEnabled(true);
        connectionFactory.setNetworkRecoveryInterval(3000);
        Connection connection = connectionFactory.newConnection();
        
        Channel channel = connection.createChannel();  
        //4 声明交换机名称 ,注意它必须与生产端一致
        String exchangeName = "direct_exchange";
        String exchangeType = "direct";
        // 队列名称随便取,意思意思 ,绑定就行
        String queueName = "direct_queue";
        // 必须与生产端一致
        String routingKey = "direct.routingKey";
        
        //表示声明了一个交换机
        channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
        //表示声明了一个队列
        channel.queueDeclare(queueName, false, false, false, null);
        //建立一个绑定关系:
        channel.queueBind(queueName, exchangeName, routingKey);
        
        //durable 是否持久化消息
        QueueingConsumer consumer = new QueueingConsumer(channel);
        //参数:队列名称、是否自动ACK、Consumer
        channel.basicConsume(queueName, true, consumer);  
        //循环获取消息  
        while(true){  
            //获取消息,如果没有消息,这一步将会一直阻塞  
            Delivery delivery = consumer.nextDelivery();  
            String msg = new String(delivery.getBody());    
            System.out.println("收到消息:" + msg);  
        } 
    }

   消息只能路由到一个 队列中。。。。

 

2.2 topic 交换机

  direct 类型的交换机只能一对一的传递消息,而topic类型的交换机就牛逼了, 它支持糊糊匹配,啥意思呢?

  在direct类型的交换机中,生产端和消息端的routingKey必须一样一样的,否则就不能拿到消息。 而topic类型就不一样了,譬如: 生产端的routingKey是 zheng.qin.feng,消息端的routingKey可以弄成以下这些都行: 

  zheng.#

  #.feng

  zheng.qin.*

  总之,对于topic类型的交换机而言,一切都是看routingKey,如果消息端队列与交换机绑定时routingKey同生产端与交换机绑定的routingKey有一定龌蹉关系,那么消息最终就会投递到该队列中。

  注意: 消息都是存储在队列中的,交换机只会转发消息,不会存储

      # : 任意词匹配

      * : 单词匹配

  

    /**
     * 生产端
     */ 
    public static void main(String[] args) throws Exception {
        
        //1 创建ConnectionFactory
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        //2 创建Connection
        Connection connection = connectionFactory.newConnection();
        //3 创建Channel
        Channel channel = connection.createChannel();  
        //4 声明
        String exchangeName = "topic_exchange";
        String routingKey1 = "user.mmp";
        String routingKey2 = "user.exchange";
        String routingKey3 = "user.test";
        //5 发送
        String msg = "abc lfkdfjdlfjdlfkdlkfdlf";
        channel.basicPublish(exchangeName, routingKey1 , null , msg.getBytes()); 
        channel.basicPublish(exchangeName, routingKey2 , null , msg.getBytes());     
        channel.basicPublish(exchangeName, routingKey3 , null , msg.getBytes()); 
        channel.close();  
        connection.close();  
    }
    

 

/**
     *  消费者
     */
    public static void main(String[] args) throws Exception {
        
        
        ConnectionFactory connectionFactory = new ConnectionFactory() ;  
        
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        connectionFactory.setAutomaticRecoveryEnabled(true);
        connectionFactory.setNetworkRecoveryInterval(3000);
        Connection connection = connectionFactory.newConnection();
        
        Channel channel = connection.createChannel();  
        //4 声明
        String exchangeName = "topic_exchange";
        String exchangeType = "topic";
        String queueName = "topic_queue";
        String routingKey = "user.*";
        // 1 声明交换机 
        channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
        // 2 声明队列
        channel.queueDeclare(queueName, false, false, false, null);
        // 3 建立交换机和队列的绑定关系:
        channel.queueBind(queueName, exchangeName, routingKey);
        
        //durable 是否持久化消息
        QueueingConsumer consumer = new QueueingConsumer(channel);
        //参数:队列名称、是否自动ACK、Consumer
        channel.basicConsume(queueName, true, consumer);  
        //循环获取消息  
        while(true){  
            //获取消息,如果没有消息,这一步将会一直阻塞  
            Delivery delivery = consumer.nextDelivery();  
            String msg = new String(delivery.getBody());    
            System.out.println("收到消息:" + msg);  
        } 
    }

   消息根据routingKey来决定路由到哪些队列中。。。。。

 

2.3 fanout交换机

  这个没啥说的,跟routingKey木有关系,只要是绑定到fanout类型交换机上的队列,都能拿到消息。

  简单的讲: 就是1 对多 的关系,, 比 topic类型的交换机还是滥情,毕竟topic交换机看不上丑女,fanout呢,是个女人都行。

 

// 生产者
    public static void main(String[] args) throws Exception {
        
        //1 创建ConnectionFactory
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        //2 创建Connection
        Connection connection = connectionFactory.newConnection();
        //3 创建Channel
        Channel channel = connection.createChannel();  
        //4 声明
        String exchangeName = "test_fanout_exchange";
        //5 发送
        for(int i = 0; i < 10; i ++) {
            String msg = "hahahah";
            channel.basicPublish(exchangeName, "", null , msg.getBytes());             
        }
        channel.close();  
        connection.close();  
    }

 

// 消息者
    public static void main(String[] args) throws Exception {
        
        ConnectionFactory connectionFactory = new ConnectionFactory() ;  
        
        connectionFactory.setHost("127.0.0.1");
        connectionFactory.setPort(5672);
        connectionFactory.setVirtualHost("/");
        
        connectionFactory.setAutomaticRecoveryEnabled(true);
        connectionFactory.setNetworkRecoveryInterval(3000);
        Connection connection = connectionFactory.newConnection();
        
        Channel channel = connection.createChannel();  
        //4 声明
        String exchangeName = "fanout_exchange";
        String exchangeType = "fanout";
        String queueName = "test_fanout_queue";
        String routingKey = "";    //不设置路由键,设置也可以,无所谓呀, 反正都行
        channel.exchangeDeclare(exchangeName, exchangeType, true, false, false, null);
        channel.queueDeclare(queueName, false, false, false, null);
        channel.queueBind(queueName, exchangeName, routingKey);
        
        //durable 是否持久化消息
        QueueingConsumer consumer = new QueueingConsumer(channel);
        //参数:队列名称、是否自动ACK、Consumer
        channel.basicConsume(queueName, true, consumer); 
        //循环获取消息  
        while(true){  
            Delivery delivery = consumer.nextDelivery();  
            String msg = new String(delivery.getBody());    
            System.out.println("收到消息:" + msg);  
        } 
    }

   尼玛,只要绑定到此交换机上的队列,都会被路由。。。。

 

    

  

 

 

  

  

 

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