用rabbitMQ实现消息的发布和订阅

RabbitMQ能够实现消息发布和订阅，这其中须要exchange，消息的发布者，消费者，消息队列和Exchange关系以下图

消息的生产者发出消息，而后通过Exchange转换，消息队列（queue）须要绑定Exchange，Exchange把消息发送到各个消息队列中，而后，各个消费者从消息队列中取到发布者发布的消息。

利用Java做为客户端，具体代码以下：

发布者代码

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

/**
 *
 * 用rabbitMQ实现发布订阅
 * 发布类
 * Created by wangtf on 2015/11/17.
 */
public class Emitlog {

    private static final String EXCHANGE_NAME = "logs";

    public  static  void main(String args[]) throws  Exception{
        ConnectionFactory connectionFactory = new ConnectionFactory();
        connectionFactory.setHost("localhost");
        Connection connection = connectionFactory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME,"fanout");
        String msg = "各单位请注意";
        channel.basicPublish(EXCHANGE_NAME,"",null,msg.getBytes());
        System.out.println("[send] msg: " +msg);
        channel.close();
        connection.close();
    }
}

消息接受类

import com.rabbitmq.client.*;

import java.io.IOException;

/**
 * RabbitMQ实现发布订阅的功能
 * 订阅类
 * Created by wangtf on 2015/11/17.
 */
public class ReceiveLogs {

    private static final String EXCHANGE_NAME = "logs";
    public static void main(String[] args) throws  Exception{
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.exchangeDeclare(EXCHANGE_NAME,"fanout");
        String queueName = channel.queueDeclare().getQueue();
        channel.queueBind(queueName,EXCHANGE_NAME,"");
        System.out.print("[*] waiting for message");

        DefaultConsumer consume = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String message = new String(body,"UTF-8");
                System.out.println("[x] receive message :" + message);
            }
        };

        channel.basicConsume(queueName,true,consume);
    }
}

分别运行ReceiveLogs和Emitlog，能获得以下结果：

【Emitlog】
[send] msg: 各单位请注意
Process finished with exit code 0

【ReceiveLogs】
[*] waiting for message[x] receive message :各单位请注意