7、RabbitMQ-主题模式

1、模式图

发送到主题交换的消息不能具有任意的 routing_key - 它必须是由点分隔的单词列表。

单词可以是任何内容，但通常它们指定与消息相关的一些功能。一些有效的路由键示例：“ stock.usd.nyse ”，“ nyse.vmw”，“ quick.orange.rabbit ”。路由密钥中可以包

含任意数量的单词，最多可达255个字节。

 

绑定密钥也必须采用相同的形式。主题交换背后的逻辑 类似于直接交换- 使用特定路

由密钥发送的消息将被传递到与匹配绑定密钥绑定的所有队列。但是绑定键有两个重

要的特殊情况：

*（星号）可以替代一个单词。

＃（hash）可以替换零个或多个单词。

 类型是topic

2、实践 

 生产者

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

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.util.ConnectionUtils;

public class Send {
    
    private static final String EXCHANGE_NAME = "exchange_topic";
    
    public static void main(String[] args) throws IOException, TimeoutException {
        
        Connection conn = ConnectionUtils.getConnection();
        
        Channel channel = conn.createChannel();
        
        //exchange
        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        
        String msg = "商品.....";
        
        //绑定路由
        String routingKey = "goods.add";
        channel.basicPublish(EXCHANGE_NAME, routingKey, null, msg.getBytes());
        
        channel.close();
        conn.close();
        
    }

}

 消费者1：

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

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.AMQP.BasicProperties;
import com.rabbitmq.util.ConnectionUtils;

public class Receive {
    
    private static final String QUEUE_NAME="test_topic1";
    private static final String EXCHANGE_NAME = "exchange_topic";
    
    public static void main(String[] args) throws IOException, TimeoutException {
        
        Connection conn = ConnectionUtils.getConnection();
        
        Channel channel = conn.createChannel();
        
        //队列声明
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        
        channel.basicQos(1);
        
        //绑定队列到交换机转发器
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "goods.add");

                //定义一个消费者
                Consumer consumer = new DefaultConsumer(channel){
                    //收到消息就会触发这个方法
                    @Override
                    public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body)
                            throws IOException {
                        String msg = new String(body,"utf-8");
                        System.out.println("消费者1接收到的消息" + msg);
                        
                        try {
                            Thread.sleep(1500);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }finally{
                            System.out.println("消费者1处理完成！");
                            //手动回执
                            channel.basicAck(envelope.getDeliveryTag(), false);
                        }
                    }
                };
                //监听队列
                //自动应答false
                boolean autoAck = false;
                channel.basicConsume(QUEUE_NAME, autoAck, consumer);
    }
}

 消费者2：

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

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.AMQP.BasicProperties;
import com.rabbitmq.util.ConnectionUtils;

public class Receive2 {
    
    private static final String QUEUE_NAME="test_topic2";
    private static final String EXCHANGE_NAME = "exchange_topic";
    public static void main(String[] args) throws IOException, TimeoutException {
        Connection conn = ConnectionUtils.getConnection();
        Channel channel = conn.createChannel();
        
        //队列声明
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        channel.basicQos(1);
        
        //绑定队列到交换机转发器
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, "goods.#");
        
                //定义一个消费者
                Consumer consumer = new DefaultConsumer(channel){
                    //收到消息就会触发这个方法
                    @Override
                    public void handleDelivery(String consumerTag, Envelope envelope, BasicProperties properties, byte[] body)
                            throws IOException {
                        String msg = new String(body,"utf-8");
                        System.out.println("消费者2接收到的消息" + msg);
                        
                        try {
                            Thread.sleep(1500);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }finally{
                            System.out.println("消费者2处理完成！");
                            //手动回执
                            channel.basicAck(envelope.getDeliveryTag(), false);
                        }
                    }
                };
                //监听队列
                //自动应答false
                boolean autoAck = false;
                channel.basicConsume(QUEUE_NAME, autoAck, consumer);
    }
}

此时如果生产者的String routingKey = "goods.add";

此时2个消费者都可以收到消息

若：String routingKey = "goods.del";

此时只有消费者2收到消息