分布式消息队列:Rabbitmq(2)

目录

一:交换机

1:Direct交换机

1.1生产者端代码:

 1.2:消费者端代码:

2:Topic主题交换机 

2.1:生产者代码: 

2.2:消费者代码:

 二:核心特性

2.1:消息过期机制

2.1.1:给队列中的全部消息指定过期时间

2.1.2:给某条消息指定过期时间 

2.2:死信队列

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一:交换机

1:Direct交换机

绑定:让交换机和队列进行关联，可以指定让交换机把什么样的消息发送给队列。

rountingkey:路由键，控制消息要发送哪个队列。

特点:根据路由键指定要转发到指定的队列

场景:特定的消息指定给特定的队列

1.1生产者端代码:

我们规定，通过控制台输入消息和路由，来指定谁完成该任务。

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

import java.util.Scanner;

public class DirectProducer {


        private static final String EXCHANGE_NAME = "2";

        public static void main(String[] argv) throws Exception {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            try (Connection connection = factory.newConnection();
                 Channel channel = connection.createChannel()) {
                //创建交换机的名称
                channel.exchangeDeclare(EXCHANGE_NAME, "direct");
                Scanner scanner=new Scanner(System.in);
                while(scanner.hasNext()){
                    String userInput=scanner.nextLine();
                    String[] s = userInput.split(" ");
                    if(s.length<1){
                        continue;
                    }
                    //指定路由key
                    String message=s[0];
                    String routingKey=s[1];
                    //发布消息
                    /*
                      第一个参数:发布到哪个交换机
                      第二个参数:路由键
                     */
                    channel.basicPublish(EXCHANGE_NAME,routingKey,null,message.getBytes("UTF-8"));
                    System.out.println("[x] Sent"+message+"with rounting"+routingKey+" ");
                }


            }
        }
        //..

    }

 1.2:消费者端代码:

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

import java.util.Scanner;

public class DirectProducer {


        private static final String EXCHANGE_NAME = "2";

        public static void main(String[] argv) throws Exception {
            ConnectionFactory factory = new ConnectionFactory();
            factory.setHost("localhost");
            try (Connection connection = factory.newConnection();
                 Channel channel = connection.createChannel()) {
                //创建交换机的名称
                channel.exchangeDeclare(EXCHANGE_NAME, "direct");
                Scanner scanner=new Scanner(System.in);
                while(scanner.hasNext()){
                    String userInput=scanner.nextLine();
                    String[] s = userInput.split(" ");
                    if(s.length<1){
                        continue;
                    }
                    //指定路由key
                    String message=s[0];
                    String routingKey=s[1];
                    //发布消息
                    /*
                      第一个参数:发布到哪个交换机
                      第二个参数:路由键
                     */
                    channel.basicPublish(EXCHANGE_NAME,routingKey,null,message.getBytes("UTF-8"));
                    System.out.println("[x] Sent"+message+"with rounting"+routingKey+" ");
                }


            }
        }
        //..

    }

运行结果:

2:Topic主题交换机 

特点:消息会根据一个模糊的路由键转发到指定的队列中。

场景:特定的一类消息只交给特定的一类系统(程序来处理)。

绑定关系:模糊匹配消息队列  *:匹配一个单词       #:匹配0个或多个单词

2.1:生产者代码: 

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

import java.util.Scanner;

public class TopicProducer {
    private static final String EXCHANGE_NAME = "3";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {

            channel.exchangeDeclare(EXCHANGE_NAME, "topic");
            Scanner scanner=new Scanner(System.in);
            while(scanner.hasNext()){
                String userInput=scanner.nextLine();
                String[] s = userInput.split(" ");
                if(s.length<1){
                    continue;
                }
                //指定路由key
                String message=s[0];
                String routingKey=s[1];
                //发布消息
                    /*
                      第一个参数:发布到哪个交换机
                      第二个参数:路由键
                     */
                channel.basicPublish(EXCHANGE_NAME,routingKey,null,message.getBytes("UTF-8"));
                System.out.println("[x] Sent"+message+"with rounting"+routingKey+" ");
            }

        }
    }
}

2.2:消费者代码:

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



public class TopicConsumer {
    private static final String EXCHANGE_NAME = "3";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, "topic");
        //创建消息队列
        String queueName="fronted_queue";
        channel.queueDeclare(queueName,true,false,false,null);
        channel.queueBind(queueName,EXCHANGE_NAME,"#.前端.#");
        String queueName2="backed-_queue";
        channel.queueDeclare(queueName2,true,false,false,null);
        channel.queueBind(queueName2,EXCHANGE_NAME,"#.后端.#");
        String queueName3="product_queue";
        channel.queueDeclare(queueName3,true,false,false,null);
        channel.queueBind(queueName3,EXCHANGE_NAME,"#.产品.#");
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

        DeliverCallback deliverCallback1 = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [前端] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        DeliverCallback deliverCallback2 = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [后端] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        DeliverCallback deliverCallback3 = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [产品] Received '" +
                    delivery.getEnvelope().getRoutingKey() + "':'" + message + "'");
        };
        channel.basicConsume(queueName, true, deliverCallback1, consumerTag -> { });
        channel.basicConsume(queueName2, true, deliverCallback2, consumerTag -> { });
        channel.basicConsume(queueName3, true, deliverCallback3, consumerTag -> { });
    }

}

运行结果:

 二:核心特性

2.1:消息过期机制

特点:给每条消息指定一个有效期，一段时间内未被消费，就过期了。

2.1.1:给队列中的全部消息指定过期时间

在消费者中对于队列的全部消息指定过期时间，如果在过期时间内，还没有消费者取消息，消息才会过期，如果消息已经接收到，但是没确认，是不会过期的。

public class TTLConsumer {

    private final static String QUEUE_NAME = "ttl_queue";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        //创建频道，提供通信
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        //指定消息队列的过期时间
        Map args=new HashMap<>();
        args.put("x-message-ttl",5000);
        //args:指定参数
        channel.queueDeclare(QUEUE_NAME, false, false,false, args);
        System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
        //如何处理消息
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" [x] Received '" + message + "'");
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}

2.1.2:给某条消息指定过期时间 

//在发送者这边设置过期时间
public class TTLProducer {

    private final static String QUEUE_NAME = "ttl_queue";

    public static void main(String[] argv) throws Exception {
        //创建连接工厂
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             //频道相当于客户端(jdbcClient,redisClient),提供了和消队列server建立通信，程序通过channel进行发送消息
             Channel channel = connection.createChannel()) {
            //创建消息队列，第二个参数(durable):是否开启持久化,第三个参数exclusiove:是否允许当前这个创建消息队列的
            //连接操作消息队列 第四个参数:没有人使用队列，是否需要删除
            String message = "Hello World!";
            //给消息指定过期时间
            AMQP.BasicProperties properties=new AMQP.BasicProperties.Builder()
                    .expiration("1000")
                            .build();

            channel.basicPublish("", QUEUE_NAME, properties, message.getBytes(StandardCharsets.UTF_8));
            System.out.println(" [x] Sent '" + message + "'");
        }
    }

2.2:死信队列

为了保证消息的可靠性，比如每条消息都成功消费，需要提供一个容错机制，即失败的消息怎么处理，相当于死信。

死信:过期的消息，拒收的消息，处理失败的消息，消息队列满了统称为死信。

死信队列:处理死信的队列。

死信交换机:给死信队列发送消息的交换机，也存在路由绑定。

a:创建死信交换机和死信队列

   //声明死信交换机
            channel.exchangeDeclare(WORK_NAME,"direct");
            //声明死信队列
            String queueName="boss_queue";
            channel.queueDeclare(queueName,true,false,false,null);
            channel.queueBind(queueName,EXCHANGE_Name,"boss");
            String queueName2="waibao_queue";
            channel.queueDeclare(queueName2, false, false, false, null);
            channel.queueBind(queueName2,EXCHANGE_Name,"waibao");

b:给失败后的需要容错的队列绑定死信交换机

  //声明交换机
        channel.exchangeDeclare(WORK_NAME, "direct");
        Map map=new HashMap<>();
        //声明要绑定的死信交换机
        map.put("x-dead-letter-exchange",DEAD_EXCHANGE_NAME);
        //声明要绑定的死信队列

        map.put("x-dead-letter-routing-key","waibao_queue");
        //创建消息队列
        String queueName="xiaodog_queue";
        channel.queueDeclare(queueName,true,false,false,map);
        channel.queueBind(queueName,WORK_NAME,"xiaodog");
        Map map2=new HashMap<>();
        //声明要绑定的死信交换机
        map2.put("x-dead-letter-exchange",DEAD_EXCHANGE_NAME);
        map2.put("x-dead-letter-routing-key","boss_queue");
        String queueName2="xiaocat_queue";
        channel.queueDeclare(queueName2,true,false,false,map2);
        channel.queueBind(queueName2,WORK_NAME,"xiaocat");