最近公司需要使用RabbitMQ，但我之前一直使用的是ActiveMQ，對RabbitMQ進行了初步的學習，但是還不繫統，自己做了一些小測試，怕自己以後忘了

一. 背景

　　拿到程式碼以後，發現，生產者在向外傳送訊息時，指定了exchange（交換機）和routing key，但是沒有指定queue（佇列）也沒有將queue（佇列）繫結到exchange，剛開始因為不熟悉rabbitMQ，所有不知道怎麼回事，後來知道了：消費者在消費訊息時，需要宣告佇列（佇列名字隨便），並將宣告的佇列通過routing key繫結到exchange，這樣才能接收到資料，因此，生產者方需要將exchange和routing key實現告知消費者方。

二. 程式碼例項：生產者方指定了exchange（交換機）和routing key，但是不指定queue（佇列）也不將queue（佇列）繫結到exchange，佇列宣告和繫結佇列到exchange的工作由消費者方完成

　　1. 生產者方

　　　　① 生產者方程式碼

 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，併發送訊息到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 生產者方程式碼執行後，可在rabbiteMQ managerment 管理介面看到相應exchange，如下圖所示：

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

　　2. 消費者方：消費者宣告佇列，佇列名稱隨便起，並將該佇列通過生產者指定的routing key繫結的其指定的exchange上

　　　　① 消費者方程式碼

 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         // 宣告佇列
22         channel.queueDeclare(QUEUE_NAME, false, false, false, null);  
23         System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
24         
25         // 繫結佇列到交換機
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 執行效果，消費者方程式碼執行後，在rabbiteMQ managerment 管理介面可以看到宣告的佇列，並發現該佇列已經繫結到了生產者指定的exchange上

---------------------------------------------------------------------------------------------------------------------------------------------------------------

--------------------------------------------------------------------------------------------------------------------------------------------------------------------

---------------------------------------------------------------------------------------------------------------------------------------------------------------

 三. 程式碼例項：生產者指定exchange和routing key，宣告佇列並將佇列繫結到exchange，消費者只需從生產者繫結的佇列消費即可

　　1. 生產者

　　　　① 生產者程式碼

 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         // 宣告佇列
23         channel.queueDeclare(QUEUE_NAME, true, false, false, null);
24         
25         // 繫結佇列到交換機
26         channel.queueBind(QUEUE_NAME, "FILETOPIC", "KEY.FILE");
27         
28         // 指定exchange和routing key，併發送訊息到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 生產者執行效果：生產者程式碼執行後，在rabbiteMQ managerment 管理介面可以看到生產者宣告的佇列，並發現該佇列已經繫結到了生產者指定的exchange上，如下圖所示：

　　2. 消費者

　　　　① 消費者程式碼：消費者現在直接消費佇列中的訊息即可，既不用宣告佇列，也不用繫結

 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 消費者執行效果：在rabbiteMQ managerment 管理介面可以看到，生產者指定的佇列已經有了消費者