RabbitMQ(四)

准备：

　　这节主要讲解Rabbit的发布/订阅。前面我们所讲的是生产者将消息直接放到队列，然后消费者再从队列中获取消息。但实际上，RabbitMQ中消息传递模型的核心思想是：生产者不直接发送消息到队列。实际的运行环境中，生产者是不知道消息会发送到那个队列上，它只会将消息发送到一个交换器，交换器也像一个生产线，一边接收生产者发来的消息，另外一边则根据交换规则，将消息放到队列中。交换器必须知道它所接收的消息是什么？它应该被放到哪个队列中？它应该被添加到多个队列吗？还是应该丢弃？这些规则都是按照交换器的规则来确定的。

　　交换机的规则有：

　　　　direct(直连)、topic(主题)、headers(标题)、fanout(分发/扇出)

　　匿名交换器：
　　　　在之前的教程中，我们知道，发送消息到队列时根本没有使用交换器，但是消息也能发送到队列。这是因为RabbitMQ选择了一个空“”字符串的默认交换器。
　　　　　　channel.basicPublish("", "task_queue", null, message.getBytes());

　　　　　　第一个参数就是交换器的名称。如果输入""空字符串，表示使用默认的匿名交换器。

　　　　　　第二个参数是【routingKey】路由线索

　　　　　　根据匿名交换器规则： 发送到routingKey名称对应的队列。

　　临时队列：

　　　　如果要在生产者和消费者之间创建一个新的队列，又不想使用原来的队列，临时队列就是为这个场景而生的：

1. 首先，每当我们连接到RabbitMQ，我们需要一个新的空队列，我们可以用一个随机名称来创建，或者说让服务器选择一个随机队列名称给我们。
2. 一旦我们断开消费者，队列应该立即被删除。

　　　　在JAVA客户端，提供queuedeclare()为我们创建一个非持久化、独立、自动删除的队列名称。

　　　　　　String queueName = channel.queueDeclare().getQueue();//获取到一个随机队列名称。

下面我们就讲解不同交换机的使用：

一：fanout(分发/扇出):每个消费者得到相同的消息，与队列绑定时，不需要绑定值routingKey（即queueBind的第三个参数），有也会忽略

　　首先创建一个生产类EmitLog

package com.exchange;

import java.io.IOException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class EmitLog {
    private static final String EXCHANGE_NAME = "logs";
    
    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        
        //创建一个交换机，并设置名称和类型
        //fanout表示分发，所以的消费者得到同样的队列信息
        channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
        
        //分发信息
        for(int i=0; i<5; i++){
            String message = "Hello World:" + i;
            channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes());
            System.out.println("EmitLog Send:" + message);
        }
        
        channel.close();
        connection.close();
    }
}

　　然后创建两个消费者ReceiveLogs1和ReceiveLogs2

package com.exchange;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.AMQP;

public class ReceiveLogs1 {
    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws IOException, TimeoutException {
          ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
    
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            
            //产生一个随机队列的名称
            String queueName = channel.queueDeclare().getQueue();
            //将交换机和随机队列进行绑定
            channel.queueBind(queueName, EXCHANGE_NAME,"");
            
            System.out.println("ReceiveLogs1 Waiting for message");
            Consumer consumer = new DefaultConsumer(channel){
                @Override
                public void handleDelivery(String consumerTag,
                        Envelope envelope,
                        AMQP.BasicProperties properties,
                        byte[] body) throws UnsupportedEncodingException{
                    String message = new String(body,"UTF-8");
                    System.out.println("ReceiveLogs1 Received:" + message);
                }
            };
            
            channel.basicConsume(queueName, true,consumer);
    }
}

package com.exchange;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class ReceiveLogs2 {
    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws IOException, TimeoutException {
          ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
    
            channel.exchangeDeclare(EXCHANGE_NAME, "fanout");
            
            //产生一个随机队列的名称
            String queueName = channel.queueDeclare().getQueue();
            //将交换机和随机队列进行绑定
            channel.queueBind(queueName, EXCHANGE_NAME,"");
            
            System.out.println("ReceiveLogs2 Waiting for message");
            Consumer consumer = new DefaultConsumer(channel){
                @Override
                public void handleDelivery(String consumerTag,
                        Envelope envelope,
                        AMQP.BasicProperties properties,
                        byte[] body) throws UnsupportedEncodingException{
                    String message = new String(body,"UTF-8");
                    System.out.println("ReceiveLogs2 Received:" + message);
                }
            };
            
            channel.basicConsume(queueName, true,consumer);
    }
}

然后先运行两个消费者，等待接收队列的消息，最后运行生产者，最终结果如下：

　　可以看出，两个消费者都得到了队列中的消息。

二：direct（直连）：采用路由的方式对不同的消息进行过滤，与队列绑定时，根据绑定值routingKey（即queueBind的第三个参数）来分发消息。同时，多个队列可以以相同的路由关键字绑定到同一个交换器中。

　　首先创建生产端的代码。

package com.mq.exchange.direct;

import java.io.IOException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class RoutingSendDirect {
    private static final String EXCHANGE_NAME = "direct_logs";
    //路由关键字routing key
    private static final String[] routingKeys = new String[]{"info","warning","error"};
    
    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        
        //声明交换机，类型是dierct直连
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        
        //发送消息
        for(String routingKey : routingKeys){
            String message = "RoutingSendDirect Send the Message level:" + routingKey;
            channel.basicPublish(EXCHANGE_NAME, routingKey, null, message.getBytes());
            System.out.println("RoutingSendDirect Send " + routingKey + ":" + message);
        }
        
        channel.close();
        connection.close();
    }
}

　　接着分别创建两个消费者：

package com.mq.exchange.direct;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class ReceiveLogsDirect1 {
    private static final String EXCHANGE_NAME = "direct_logs";
    private static final String[] routingKeys = new String[]{"info","warning"};
    
    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        //产生一个随机队列名称
        String queueName = channel.queueDeclare().getQueue();
        
        //根据路由关键字来进行队列和交换机的绑定
        //这里一个队列绑定两个路由关键字（info,warning），即此队列可以获取交换机中routingKey为info和warning的消息
        for(String routingKey : routingKeys){
            channel.queueBind(queueName, EXCHANGE_NAME, routingKey);
            System.out.println("ReceiveLogsDirect1 exchange:" + EXCHANGE_NAME + ",queue:" 
                                + queueName +",BindRoutingKey:" +routingKey );
        }
        System.out.println("ReceiveLogsDirect1 Waiting for message");
        Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag,
                    Envelope envelope,
                    AMQP.BasicProperties properties,
                    byte[] body) throws UnsupportedEncodingException{
                String message = new String(body,"UTF-8");
                System.out.println("ReceiveLogsDirect1 Received " + envelope.getRoutingKey() +":" + message);
            }
        };
            
        channel.basicConsume(queueName, true, consumer);
    }
}

package com.mq.exchange.direct;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class ReceiveLogsDirect2 {
    private static final String EXCHANGE_NAME = "direct_logs";
    private static final String[] routingKeys = new String[]{"error"};
    
    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");
        //产生一个随机队列名称
        String queueName = channel.queueDeclare().getQueue();
        
        //根据路由关键字来进行队列和交换机的绑定
        //这里一个队列绑定两个路由关键字（info,warning），即此队列可以获取交换机中routingKey为info和warning的消息
        for(String routingKey : routingKeys){
            channel.queueBind(queueName, EXCHANGE_NAME, routingKey);
            System.out.println("ReceiveLogsDirect2 exchange:" + EXCHANGE_NAME + ",queue:" 
                                + queueName +",BindRoutingKey:" +routingKey );
        }
        System.out.println("ReceiveLogsDirect2 Waiting for message");
        Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag,
                    Envelope envelope,
                    AMQP.BasicProperties properties,
                    byte[] body) throws UnsupportedEncodingException{
                String message = new String(body,"UTF-8");
                System.out.println("ReceiveLogsDirect2 Received " + envelope.getRoutingKey() + ":" + message);
            }
        };
            
        channel.basicConsume(queueName, true, consumer);
    }
}

　　接着先运行两个消费者，等待接收队列的消息，最后运行生产者，最终结果如下：

三：headers（标题）：此类型的exchange使用的比较少，它也是忽略routingKey的一种路由方式。是使用Headers来匹配的。Headers是一个键值对，可以定义成Hashtable。

　　发送者在发送的时候定义一些键值对，接收者也可以再绑定时候传入一些键值对，两者匹配的话，则对应的队列就可以收到消息。匹配有两种方式all和any。这两种方式是在接收端必须要用键值"x-mactch"来定义。all代表定义的多个键值对都要满足，而any则代码只要满足一个就可以了。fanout，direct，topic exchange的routingKey都需要要字符串形式的，而headers exchange则没有这个要求，因为键值对的值可以是任何类型。

实例：

　　创建一个生产者类：

package com.mq.exchange.headers;

import java.io.IOException;
import java.util.Hashtable;
import java.util.Map;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP.BasicProperties.Builder;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class Producer {
    private final static String EXCHANGE_NAME = "header-exchange";
    
    public static void main(String[] args) throws IOException, TimeoutException {
             ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
            
            //创建一个交换机，并设置名称和类型
            //参数1：交换机名称
            //参数2：交换机类型
            //参数3：是否持久化
            //参数4：是否自动删除
            //参数5：交换机的其他参数
            channel.exchangeDeclare(EXCHANGE_NAME,"headers",false,true,null);  
            
            Map<String, Object> map =new Hashtable<String, Object>();
            map.put("ABC", "12345");
            
            //创建properties
            Builder properties = new Builder(); 
            //把map放入headers中
            properties.headers(map);
            //持久化,参数：1表示不持久话，2表示持久化
            properties.deliveryMode(2);
            
            //指定消息发送到交换机，绑定键值对headers
            String message = "Hello RabbitMQ：headers";
            channel.basicPublish(EXCHANGE_NAME, "", properties.build(),message.getBytes());
            
            System.out.println("Producer Sent message :'" + message + "'");
            
            channel.close();
            connection.close();
    }
}

　　创建一个消费者类：

package com.mq.exchange.headers;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.Hashtable;
import java.util.Map;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class Consumer {
    private final static String EXCHANGE_NAME = "header-exchange";  

    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        
        channel.exchangeDeclare(EXCHANGE_NAME,"headers",false,true,null);  
        
        Map<String, Object> getMap = new Hashtable<String, Object>();  
        //all和any,any有一个键值对匹配即可
        getMap.put("x-match", "any"); 
        getMap.put("ABC", "12345");  
        getMap.put("abc", "54321");  
        
        //产生一个随机队列的名称
        String queueName = channel.queueDeclare().getQueue();
        //将交换机和随机队列进行绑定,并指定绑定的header键值对
        channel.queueBind(queueName, EXCHANGE_NAME,"",getMap);
        
        com.rabbitmq.client.Consumer consumer = new DefaultConsumer(channel){
            @Override
            public void handleDelivery(String consumerTag,
                    Envelope envelope,
                    AMQP.BasicProperties properties,
                    byte[] body) throws UnsupportedEncodingException{
                String message = new String(body,"UTF-8");
                System.out.println("Consumer Received:" + message);
            }
        };
        
        channel.basicConsume(queueName, true,consumer);
    }
}

　　先运行消费者，然后运行生产者，得到结果如下：

四：topic（主题）：这种应该属于模糊匹配 *：可以替代一个词 #：可以替代0或者更多的词

　　下面我们看下实例来了解了解。

　　首先创建一个发送类TopicSend

package com.mq.exchange.topic;

import java.io.IOException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;

public class TopicSend {
     private static final String EXCHANGE_NAME = "topic_logs";
     
     public static void main(String[] args) throws IOException, TimeoutException {
             ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
            
            channel.exchangeDeclare(EXCHANGE_NAME,"topic"); 
            
            //待发送的消息
            String[] routingKeys=new String[]{
                    "quick.orange.rabbit",
                    "lazy.orange.elephant",
                    "quick.orange.fox",
                    "lazy.brown.fox",
                    "quick.brown.fox",
                    "quick.orange.male.rabbit",
                    "lazy.orange.male.rabbit"
            };
            
            //发送消息
            for(String routing : routingKeys){
                String message = "From " + routing + "routingKeys message" ;
                channel.basicPublish(EXCHANGE_NAME, routing, null, message.getBytes());
                System.out.println("TopicSend Send " + routing + ":" + message);
            }
            
            channel.close();
            connection.close();
    }
}

　　创建两个接收类：

package com.mq.exchange.topic;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class ReceiveLogsTopic1 {
     private static final String EXCHANGE_NAME = "topic_logs";

     public static void main(String[] args) throws IOException, TimeoutException {
         ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
            
            channel.exchangeDeclare(EXCHANGE_NAME,"topic"); 
            String queueName = channel.queueDeclare().getQueue();
            
            //路由关键字
            String[] routingKeys = new String[]{"*.orange.*"};
            
            //绑定路由
            for(String routing : routingKeys){
                channel.queueBind(queueName, EXCHANGE_NAME, routing);
                System.out.println("ReceiveLogsTopic1 exchange :" + EXCHANGE_NAME + ",queue:" 
                        + queueName +",BindRountingKey:" + routing );
            }
            
            System.out.println("ReceiveLogsTopic1 Waiting for messages");
            
            Consumer consumer = new DefaultConsumer(channel){
                  @Override
                  public void handleDelivery(String consumerTag,
                          Envelope envelope,
                          AMQP.BasicProperties properties,
                          byte[] body) throws UnsupportedEncodingException{
                      String message = new String(body,"UTF-8");
                      System.out.println("ReceiveLogsTopic1 Received " + envelope.getRoutingKey() + ":" + message);
                  }
              };
              
              channel.basicConsume(queueName, true, consumer);
    }
}

package com.mq.exchange.topic;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.concurrent.TimeoutException;
import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;

public class ReceiveLogsTopic2 {
     private static final String EXCHANGE_NAME = "topic_logs";

     public static void main(String[] args) throws IOException, TimeoutException {
         ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            Connection connection = factory.newConnection();
            Channel channel = connection.createChannel();
            
            channel.exchangeDeclare(EXCHANGE_NAME,"topic"); 
            String queueName = channel.queueDeclare().getQueue();
            
            //路由关键字
            String[] routingKeys = new String[]{"*.*.rabbit", "lazy.#"};
            
            //绑定路由
            for(String routing : routingKeys){
                channel.queueBind(queueName, EXCHANGE_NAME, routing);
                System.out.println("ReceiveLogsTopic2 exchange :" + EXCHANGE_NAME + ",queue:" 
                        + queueName +",BindRountingKey:" + routing );
            }
            
            System.out.println("ReceiveLogsTopic2 Waiting for messages");
            
            Consumer consumer = new DefaultConsumer(channel){
                  @Override
                  public void handleDelivery(String consumerTag,
                          Envelope envelope,
                          AMQP.BasicProperties properties,
                          byte[] body) throws UnsupportedEncodingException{
                      String message = new String(body,"UTF-8");
                      System.out.println("ReceiveLogsTopic2 Received " + envelope.getRoutingKey() + ":" + message);
                  }
              };
              
              channel.basicConsume(queueName, true, consumer);
    }
}

　　最后先运行两个接收类，在运行发送类，结果如下所示：

作者：哀&RT
出处：博客园哀&RT的技术博客--http://www.cnblogs.com/Tony-Anne/
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原文地址：https://www.cnblogs.com/Tony-Anne/p/6434961.html