Java使用RabbitMQ之订阅分发（Topic）

使用RabbitMQ进行消息发布和订阅，生产者将消息发送给转发器（exchange），转发器根据路由键匹配已绑定的消息队列并转发消息，主题模式支持路由键的通配。

生产者代码：

 package org.study.exchange3.topic3;

 import com.rabbitmq.client.Channel;
 import com.rabbitmq.client.Connection;
 import org.junit.Test;
 import org.study.utils.ConnectionUtils;

 import java.io.IOException;
 import java.util.concurrent.TimeoutException;

 /**
  * topic-主题模式（分发订阅）
  * exchange只转发消息，但是没有存储能力，只有队列才有存储能力
  * 主题模式支持路由键的通配符
  * “#”表示0个或若干个关键字，“*”表示一个关键字。
  */
 public class Sender {
     public static final String QUEUE_NAME = "test_topic_queue";
     public static final String EXCHANGE_NAME = "topic_exchange";

     @Test
     public void send() throws IOException, TimeoutException, InterruptedException {
         // 获取连接
         Connection conn = ConnectionUtils.getConnection();
         // 获取通道
         Channel channel = conn.createChannel();
 //        //创建队列
 //        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
         //声明转发器
         channel.exchangeDeclare(EXCHANGE_NAME, "topic");
         //每个消费者发送确认消息前，只发送一条消息
         channel.basicQos(1);

         String msg = "hello rabbitmq topic !";
         //发送消息至转发器,指定路由键
         channel.basicPublish(EXCHANGE_NAME, "key.key", null, msg.getBytes());
         System.out.println("[send] msg " + msg);

         channel.close();
         conn.close();
     }
 }

消费者代码：

 package org.study.exchange3.topic3;

 import com.rabbitmq.client.*;
 import org.junit.Test;
 import org.study.utils.ConnectionUtils;

 import java.io.IOException;
 import java.util.concurrent.TimeoutException;

 /**
  * 主题模式-接收消息
  */
 public class Recv {
     public static final String QUEUE_NAME = "test_topic_queue";
     public static final String EXCHANGE_NAME = "topic_exchange";

     @Test
     public void recv() throws IOException, TimeoutException, InterruptedException {
         Connection conn = ConnectionUtils.getConnection();
         Channel channel = conn.createChannel();
         channel.queueDeclare(QUEUE_NAME, false, false, false, null);
         channel.basicQos(1);
         /*
          * 队列绑定转发器,路由键通配符#和*
          * #：表示0个或多个字符
          * *：表示一个字符
          * */
         channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "key.#");

         //定义消费者
         DefaultConsumer consumer = new DefaultConsumer(channel) {
             //重写获取到达消息
             @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("[1] recv: " + msg);

                 try {
                     Thread.sleep(100);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 } finally {
                     System.out.println("[1] done!");
                     // 回执
                     channel.basicAck(envelope.getDeliveryTag(), false);
                 }
             }
         };

         while (true) {
             //监听队列
             channel.basicConsume(QUEUE_NAME, false, consumer);
             Thread.sleep(1000);
         }

     }
 }