RabbitMQ-发布/订阅

上篇文章中,创建一个工作队列,对应的每个任务都交给了一个消费者.那么这一部分,就学习一下,将任务分发给多个消费者.即发布-订阅
场景: 一个发送日志,一个接受者把接收到的数据写到磁盘.另一个接受者把接收到的消息,打在控制台上

Exchanges

先来回顾一下之前的概念
生产者:发送消息的用户应用程序
队列:消息存储缓冲区
消费者:接收消息的用户应用程序
对于rabbitmq来说,生产者不会将任何消息直接发送给队列的. 生产者甚至不知道消息是否会被传递到哪个队列,生产者,只是把消息发送给交换器(exchanges),交换器,用来接收生产者的消息,还把消息推送到队列.具体怎么处理生产者的消息, 是发给所有队列,还是特定队列等等,取决于交换器的类型
交换器类型:direct topic headers fanout
重点学习一下fanout,最简单最快的,发给所有的队列
创建一个交换器

//建立一个fanout类型转发器
channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);

匿名转发

//指定转发器名字:logs,空字符串表示模式或者匿名的转发器
channel.basicPublish(EXCHANGE_NAME,"",null,message.getBytes("UTF-8"));
System.out.println(" [x] Sent '" + message + "'");

临时队列

//无参queueDeclare(),创建一个非持久化,独立的,自动删除的队列,且名字是随机生成的
//queueName随机生成, 类似这样的:amq.gen-57B3VSVx-l1jawmOoRBYLw
String queueName = channel.queueDeclare().getQueue();

Binding

上面创建了一个广播转发器和一个随机队列,现在需要告诉转发器转发消息到队列.这个就叫binding

//日志转发器附加到日志队列上
channel.queueBind(queueName, EXCHANGE_NAME, "");

看看代码吧
生产者

package com.tgb.kwy.publish;

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

/**
 * Description
 *
 * @author kongwy [email protected]
 * @version 1.0
 * @date 2018-07-09-08 -41
 */
public class EmitLog {
    private static final String EXCHANGE_NAME="logs";

    public static void main(String[] args) throws java.io.IOException{
        ConnectionFactory factory=new ConnectionFactory();
        factory.setHost("192.168.159.132");/*设置rabbitmq所在主机ip或主机名*/
        /*指定用户名和密码*/
        factory.setUsername("admin");
        factory.setPassword("admin");
        try{
            Connection connection = factory.newConnection();
            Channel channel=connection.createChannel();
            //建立一个fanout类型转发器
            channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);

            String message = getMessage(args);
            //指定转发器名字:logs,空字符串表示模式或者匿名的转发器
            channel.basicPublish(EXCHANGE_NAME,"",null,message.getBytes("UTF-8"));
            System.out.println(" [x] Sent '" + message + "'");
            channel.close();
            connection.close();
        }catch (Exception e){
        }
    }
    private static String getMessage(String[] strings){
        if(strings.length<1){
            return "info: Hello World!";
        }
        return joinStrings(strings," ");
    }
    private static String joinStrings(String[] strings,String delimiter){
        int length=strings.length;
        if(length==0){
            return "";
        }
        StringBuilder words=new StringBuilder(strings[0]);
        for (int i = 0; i < length; i++) {
            words.append(delimiter).append(strings[i]);
        }
        return words.toString();
    }
}

消费者1(显示)

package com.tgb.kwy.publish;

import com.rabbitmq.client.*;

import java.io.IOException;

/**
 * Description
 *
 * @author kongwy [email protected]
 * @version 1.0
 * @date 2018-07-09-08 -46
 */
public class ReceiveLogs {
    private static final String EXCHANGE_NAME="logs";

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory=new ConnectionFactory();
        factory.setHost("192.168.159.132");/*设置rabbitmq所在主机ip或主机名*/
        /*指定用户名和密码*/
        factory.setUsername("admin");
        factory.setPassword("admin");
        Connection connection = factory.newConnection();
        final Channel channel = connection.createChannel();
        //建立一个fanout类型转发器
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);
        //无参queueDeclare(),创建一个非持久化,独立的,自动删除的队列,且名字是随机生成的
        String queueName = channel.queueDeclare().getQueue();
        //queueName随机生成, 类似这样的:amq.gen-57B3VSVx-l1jawmOoRBYLw
        //日志转发器附加到日志队列上
        channel.queueBind(queueName, EXCHANGE_NAME, "");

        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        final Consumer consumer = 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] Received '" + message + "'");
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
}

消费者2(记录文件)

package com.tgb.kwy.publish;

import com.rabbitmq.client.*;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Description
 *
 * @author kongwy [email protected]
 * @version 1.0
 * @date 2018-07-09-11 -41
 */
public class ReceiveLogFile {
    private static final String EXCHANGE_NAME="logs";

    public static void main(String[] args) throws Exception{
        ConnectionFactory factory=new ConnectionFactory();
        factory.setHost("192.168.159.132");/*设置rabbitmq所在主机ip或主机名*/
        /*指定用户名和密码*/
        factory.setUsername("admin");
        factory.setPassword("admin");
        Connection connection = factory.newConnection();
        final Channel channel = connection.createChannel();
        //建立一个fanout类型转发器
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);
        //无参queueDeclare(),创建一个非持久化,独立的,自动删除的队列,且名字是随机生成的
        String queueName = channel.queueDeclare().getQueue();
        //queueName随机生成, 类似这样的:amq.gen-57B3VSVx-l1jawmOoRBYLw
        //日志转发器附加到日志队列上
        channel.queueBind(queueName, EXCHANGE_NAME, "");

        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        final Consumer consumer = 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");
                printFile(message);
                System.out.println(" [x] Received '" + message + "'");
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
    private static void printFile(String msg){
        try{
            String dir=ReceiveLogFile.class.getClassLoader().getResource("").getPath();
            String logFileName=new SimpleDateFormat("yyyy-MM-dd").format(new Date());
            File file = new File(dir, logFileName + ".log");
            FileOutputStream fos = new FileOutputStream(file, true);
            fos.write((new SimpleDateFormat("HH:mm:ss").format(new Date())+" - "+msg + "\r\n").getBytes());
            fos.flush();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

当消费者启动之后,管理页面可以看到,随机队列

注: 运行的时候,先运行消费者,再运行生产者,否则获取不到实例

注:代码来自官网.官网对于概念性的内容,讲解的还是很清楚的