RabbitMQ 6：原生Java客户端+备用交换器

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如果主交换器无法路由消息，那么消息将被路由到这个新的备用交换器，有备用交换器时，即使消息不可路由，不会发送失败通知

1.创建生产者BackupExchangeProducer

package com.rabbit.fisher.backupexchange;

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

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeoutException;

/**
 *生产者-绑定了一个备用交换器
 */
public class BackupExchangeProducer
{
    public final static String EXCHANGE_NAME = "main-exchange";
    public final static String BACK_EXCHANGE_NAME = "back-exchange";

    public static void main( String[] args ) throws IOException, TimeoutException {
        //创建链接、连接到MQ
        ConnectionFactory connectionFactory = new ConnectionFactory();
        //设置连接工厂的连接地址(默认端口5672)
        connectionFactory.setHost("192.168.42.111");
        //设置虚拟主机
        connectionFactory.setVirtualHost("fisher");
        //设置用户名
        connectionFactory.setUsername("fisher");
        //设置密码
        connectionFactory.setPassword("123456");
        //创建连接
        Connection connection = connectionFactory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //声明备用交换器
        Map<String, Object> map = new HashMap<>();
        map.put("alternate-exchange", BACK_EXCHANGE_NAME);
        //主交换器
        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT, false, false, map);
        //备用交换器
        channel.exchangeDeclare(BACK_EXCHANGE_NAME, BuiltinExchangeType.FANOUT, true, false, null);
        //在消费者中申明队列

        //申明路由键及消息体
        String[] routeKeys={"rabbit","rocket","kafka"};
        for (int i = 0; i < 3; i++) {
            String route = routeKeys[i % 3];
            String msg = "Hello World" + (i+1);
            //发布消息(设置交换器、路由键、参数、消息内容)
            channel.basicPublish(EXCHANGE_NAME, route, null, msg.getBytes());
            System.out.println("Send:" + route + ";" + msg);
        }
        //关闭信道
        channel.close();
        //关闭连接
        connection.close();
    }
}

设置备用交换器参数 声明路由键，在绑定主交换器的消费者中只消费rabbit路由键的消息，在绑定备用交换器的消费者中广播rocket和kafka路由键的消息

2.创建绑定主交换器的消费者MainConsumer

package com.rabbit.fisher.backupexchange;

import com.rabbitmq.client.*;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeoutException;

/**
 *绑定主交换器的消费者
 */
public class MainConsumer
{

    public static void main( String[] args ) throws IOException, TimeoutException {
        //创建链接、连接到MQ
        ConnectionFactory connectionFactory = new ConnectionFactory();
        //设置连接工厂的连接地址(默认端口5672)
        connectionFactory.setHost("192.168.42.111");
        //设置虚拟主机
        connectionFactory.setVirtualHost("fisher");
        //设置用户名
        connectionFactory.setUsername("fisher");
        //设置密码
        connectionFactory.setPassword("123456");
        //创建连接
        Connection connection = connectionFactory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        Map<String, Object> map = new HashMap<>();
        map.put("alternate-exchange", BackupExchangeProducer.BACK_EXCHANGE_NAME);
        //在信道中设置交换器
        channel.exchangeDeclare(BackupExchangeProducer.EXCHANGE_NAME, BuiltinExchangeType.DIRECT, false, false, map);
        //申明队列
        String queueName = channel.queueDeclare().getQueue();
        //绑定路由键（rabbit）
        String routeKey = "rabbit";
        channel.queueBind(queueName, BackupExchangeProducer.EXCHANGE_NAME, routeKey);
        System.out.println("waiting for message ......");

        //申明一个消费者
        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("Receive[" + envelope.getRoutingKey() + "]" + message);
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
}

3.创建绑定备用交换器的消费者BackExConsumer

package com.rabbit.fisher.backupexchange;

import com.rabbitmq.client.*;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

/**
 *绑定备用交换器的消费者
 */
public class BackExConsumer
{

    public static void main( String[] args ) throws IOException, TimeoutException {
        //创建链接、连接到MQ
        ConnectionFactory connectionFactory = new ConnectionFactory();
        //设置连接工厂的连接地址(默认端口5672)
        connectionFactory.setHost("192.168.42.111");
        //设置虚拟主机
        connectionFactory.setVirtualHost("fisher");
        //设置用户名
        connectionFactory.setUsername("fisher");
        //设置密码
        connectionFactory.setPassword("123456");
        //创建连接
        Connection connection = connectionFactory.newConnection();
        //创建信道
        Channel channel = connection.createChannel();
        //在信道中设置交换器
        channel.exchangeDeclare(BackupExchangeProducer.BACK_EXCHANGE_NAME, BuiltinExchangeType.FANOUT, true, false, null);
        // 声明一个队列
        String queueName = channel.queueDeclare().getQueue();
        //fanout交换器，不需指定路由键
        channel.queueBind(queueName, BackupExchangeProducer.BACK_EXCHANGE_NAME, "xxx");
        System.out.println("waiting for message ......");

        //申明一个消费者
        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("Receive[" + envelope.getRoutingKey() + "]" + message);
            }
        };
        channel.basicConsume(queueName, true, consumer);
    }
}

4.先启动消费者MainConsumer，再启动消费者BackExConsumer，最后启动生产者BackupExchangeProducer

5.查看打印

生产者BackupExchangeProducer的打印

Send:rabbit;Hello World1
Send:rocket;Hello World2
Send:kafka;Hello World3

MainConsumer的打印

waiting for message ......
Receive[rabbit]Hello World1

BackExConsumer的打印

waiting for message ......
Receive[rocket]Hello World2
Receive[kafka]Hello World3