RabbitMQ usage scenario exercise: Routing (4)

• Routing

     Routing is to send messages according to a certain route, and all queues on this route will receive the message.
     Use the direct repeater, bind multiple queues with the same routingkey on the repeater, send messages according to the routingkey, and all bound queues will receive the message

• Points to Note

The direct forwarder forwards the message directly to the queue bound to the routingkey :

channel.exchangeDeclare("direct_logs", "direct");
channel.basicPublish("direct_logs", severity , null, SerializationUtils.serialize(object));

Binding of forwarder and queue (specifying routingkey) :

//Specify routingkey when binding temporary queue and forwarder
 channel.queueBind(queueName, "direct_logs", severity);

The default repeater used in the work queue, the repeater is also direct, the work queue is to declare multiple consumers in parallel on the same queue; Routing is used to bind multiple queues with the same routingkey on the repeater (I didn't understand it at first)

• message sending class

package com.demo.mq.rabbitmq.example04;

import java.io.IOException;
import java.io.Serializable;
import java.util.Random;

import org.apache.commons.lang3.SerializationUtils;

import com.demo.mq.rabbitmq.MqManager;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;

/**
 * Send message class
 * @author sheungxin
 *
 */
public class Send{

	/**
	 * Send a message, direct the forwarder, and match the corresponding queue by routingKey
	 * @param object message body
	 * @throws IOException
	 */
	public static void sendAToB(Serializable object) throws Exception{
		Connection conn=MqManager.newConnection();
		Channel channel=conn.createChannel();
		channel.exchangeDeclare("direct_logs", "direct");
		for(int i=0;i<4;i++){
			String severity=getSeverity();
			channel.basicPublish("direct_logs", severity , null, SerializationUtils.serialize(object));
			System.out.println(severity+":Send '"+object+"'");
		}
		channel.close();
		conn.close();
	}
	
	private static String getSeverity(){
		String[] severities=new String[]{"info","warn","error"};
		Random random=new Random();
		return severities[random.nextInt(3)];
	}
	
	public static void main(String[] args) throws Exception {
		sendAToB("Hello World !");
	}
}

• message receiving class

package com.demo.mq.rabbitmq.example04;

import java.io.IOException;
import java.util.Random;

import org.apache.commons.lang3.SerializationUtils;

import com.demo.mq.rabbitmq.MqManager;
import com.rabbitmq.client.AMQP;
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;

/**
 * Receive message class
 * @author sheungxin
 *
 */
public class Recv {
	
	/**
	 * Used to receive messages, create a temporary queue, bind to the forwarder direct, and specify routingKey
	 * @param queue
	 * @throws Exception
	 */
	public static void recvAToB() throws Exception{
		Connection conn=MqManager.newConnection();
		Channel channel=conn.createChannel();
		channel.exchangeDeclare("direct_logs", "direct");
		//create a temporary queue
		String queueName=channel.queueDeclare().getQueue();
		//Bind temporary queue and forwarder logs
		String severity=getSeverity();
		channel.queueBind(queueName, "direct_logs", severity);
		System.out.println(severity+":Received ...");
		Consumer consumer=new DefaultConsumer(channel){
			@Override
			public void handleDelivery(String consumerTag,Envelope envelope,AMQP.BasicProperties properties,byte[] body) throws IOException{
				String mes=SerializationUtils.deserialize(body);
				System.out.println(envelope.getRoutingKey()+":Received :'"+mes+"' done");
			}
		};
		//Turn off the automatic response mechanism, which is enabled by default; at this time, you need to manually perform the response
		channel.basicConsume(queueName, true, consumer);
	}
	
	private static String getSeverity(){
		String[] severities=new String[]{"info","warn","error"};
		Random random=new Random();
		return severities[random.nextInt(3)];
	}
	
	public static void main(String[] args) throws Exception {
		recvAToB ();
	}

}