最近公司需要使用RabbitMQ，但我之前一直使用的是ActiveMQ，对RabbitMQ进行了初步的学习，但是还不系统，自己做了一些小测试，怕自己以后忘了
一. 背景
拿到代码以后，发现，生产者在向外发送消息时，指定了exchange（交换机）和routing key，但是没有指定queue（队列）也没有将queue（队列）绑定到exchange，刚开始因为不熟悉rabbitMQ，所有不知道怎么回事，后来知道了：消费者在消费消息时，需要声明队列（队列名字随便），并将声明的队列通过routing key绑定到exchange，这样才能接收到数据，因此，生产者方需要将exchange和routing key实现告知消费者方。
二. 代码实例：生产者方指定了exchange（交换机）和routing key，但是不指定queue（队列）也不将queue（队列）绑定到exchange，队列声明和绑定队列到exchange的工作由消费者方完成
1. 生产者方
① 生产者方代码
1 import java.io.IOException; 2 import com.rabbitmq.client.Channel; 3 import com.rabbitmq.client.Connection; 4 import com.rabbitmq.client.ConnectionFactory; 5
6 public class Producer { 7 private final static String QUEUE_NAME = “QUEUE8”;
8
9 public static void main(String[] args) throws IOException { 10
11 ConnectionFactory factory = new ConnectionFactory(); 12 factory.setHost(“localhost”); 13 factory.setPort(5672); 14 factory.setUsername(“guest”); 15 factory.setPassword(“guest”); 16
17 Connection connection = factory.newConnection(); 18 Channel channel = connection.createChannel(); 19
20 String message = “Hello World!”; 21
22 // 指定exchange和routing key，并发送消息到exchange
23 channel.basicPublish(“FILETOPIC”, “KEY.FILE”, null, message.getBytes()); 24 System.out.println(“ [x] Sent ‘“ + message + “‘“); 25
26 channel.close(); 27 connection.close(); 28 } 29 }
② 生产者方代码运行后，可在rabbiteMQ managerment 管理界面看到相应exchange，如下图所示：
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2. 消费者方：消费者声明队列，队列名称随便起，并将该队列通过生产者指定的routing key绑定的其指定的exchange上
① 消费者方代码
1 import com.rabbitmq.client.ConnectionFactory; 2 import com.rabbitmq.client.QueueingConsumer; 3 import com.rabbitmq.client.Channel; 4 import com.rabbitmq.client.Connection; 5
6 public class Reqv { 7
8 private final static String QUEUE_NAME = “QUEUE8”;
9
10 public static void main(String[] argv) throws Exception { 11
12 ConnectionFactory factory = new ConnectionFactory(); 13 factory.setPort(5672); 14 factory.setUsername(“guest”); 15 factory.setPassword(“guest”); 16 factory.setHost(“localhost”); 17
18 Connection connection = factory.newConnection(); 19 Channel channel = connection.createChannel(); 20
21 // 声明队列
22 channel.queueDeclare(QUEUE_NAME, false, false, false, null); 23 System.out.println(“ [*] Waiting for messages. To exit press CTRL+C”); 24
25 // 绑定队列到交换机
26 channel.queueBind(QUEUE_NAME, “FILETOPIC”, “KEY.FILE”); 27
28 QueueingConsumer consumer = new QueueingConsumer(channel); 29 channel.basicConsume(QUEUE_NAME, true, consumer); 30 while(true){ 31 QueueingConsumer.Delivery delivery = consumer.nextDelivery(); 32 String message = new String(delivery.getBody(),”UTF-8”); 33 System.out.println(“ 【[x] Received 】：” + message); 34 } 35 } 36 }
② 运行效果，消费者方代码运行后，在rabbiteMQ managerment 管理界面可以看到声明的队列，并发现该队列已经绑定到了生产者指定的exchange上
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三. 代码实例：生产者指定exchange和routing key，声明队列并将队列绑定到exchange，消费者只需从生产者绑定的队列消费即可
1. 生产者
① 生产者代码
1 import java.io.IOException; 2 import com.rabbitmq.client.Channel; 3 import com.rabbitmq.client.Connection; 4 import com.rabbitmq.client.ConnectionFactory; 5
6 public class Producer { 7 private final static String QUEUE_NAME = “QUEUE1”;
8
9 public static void main(String[] args) throws IOException { 10
11 ConnectionFactory factory = new ConnectionFactory(); 12 factory.setHost(“localhost”); 13 factory.setPort(5672); 14 factory.setUsername(“guest”); 15 factory.setPassword(“guest”); 16
17 Connection connection = factory.newConnection(); 18 Channel channel = connection.createChannel(); 19
20 String message = “Hello World!”; 21
22 // 声明队列
23 channel.queueDeclare(QUEUE_NAME, true, false, false, null); 24
25 // 绑定队列到交换机
26 channel.queueBind(QUEUE_NAME, “FILETOPIC”, “KEY.FILE”); 27
28 // 指定exchange和routing key，并发送消息到exchange
29 channel.basicPublish(“FILETOPIC”, “KEY.FILE”, null, message.getBytes()); 30 System.out.println(“ [x] Sent ‘“ + message + “‘“); 31
32 channel.close(); 33 connection.close(); 34 } 35 }
② 生产者运行效果：生产者代码运行后，在rabbiteMQ managerment 管理界面可以看到生产者声明的队列，并发现该队列已经绑定到了生产者指定的exchange上，如下图所示：
2. 消费者
① 消费者代码：消费者现在直接消费队列中的消息即可，既不用声明队列，也不用绑定
1 import com.rabbitmq.client.ConnectionFactory; 2 import com.rabbitmq.client.QueueingConsumer; 3 import com.rabbitmq.client.Channel; 4 import com.rabbitmq.client.Connection; 5
6 public class Reqv { 7
8 private final static String QUEUE_NAME = “QUEUE1”;
9
10 public static void main(String[] argv) throws Exception { 11
12 ConnectionFactory factory = new ConnectionFactory(); 13 factory.setPort(5672); 14 factory.setUsername(“guest”); 15 factory.setPassword(“guest”); 16 factory.setHost(“localhost”); 17
18 Connection connection = factory.newConnection(); 19 Channel channel = connection.createChannel(); 20
21 QueueingConsumer consumer = new QueueingConsumer(channel); 22 channel.basicConsume(QUEUE_NAME, true, consumer); 23 while(true){ 24 QueueingConsumer.Delivery delivery = consumer.nextDelivery(); 25 String message = new String(delivery.getBody(),”UTF-8”); 26 System.out.println(“ 【[x] Received 】：” + message); 27 } 28 } 29 }
② 消费者运行效果：在rabbiteMQ managerment 管理界面可以看到，生产者指定的队列已经有了消费者
