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RabbitMQ入门-路由-有选择的接受消息

news 来源：原创 2024/5/17 0:39:42

比如一个日志系统，之前的处理方式呢，是各种类型（info，error，warning）的消息都发给订阅者，可是实际情况上不一定都需要。可能A需要error，其他的都不需要。那么就引入了今天的处理方式--路由（直接交换）

（兔子的官网真心良心，图文并茂，通俗易懂）这种处理方式你只需记住一个字：有选择的接受消息

首先，我们将消息绑定在不同的路由键上，然后消费者根据需要绑定对应的路由键即可收到消息。路由键随便取名字

生产者代码：

package com.example.demo;

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

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

/**
 * 有选择的接受消息
 */
public class RoutingSend {

    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();    // 连接工厂
        factory.setHost("localhost");
        Connection connection = factory.newConnection();        // 获取连接
        Channel channel = connection.createChannel();

        // 当我们发送时，需要一个路由密钥，这里选择直接交换
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");

        String[] msg = {"错误","信息","警告"};
        // 第二个参数为路由密钥
        channel.basicPublish(EXCHANGE_NAME, "error", null, msg[0].getBytes());
        channel.basicPublish(EXCHANGE_NAME, "info", null, msg[1].getBytes());
        channel.basicPublish(EXCHANGE_NAME, "warning", null, msg[2].getBytes());
        System.out.println("PS-Send:" + msg.toString());

        channel.close();
        connection.close();

    }
}

消费者代码：

package com.example.demo;

import com.rabbitmq.client.*;

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

public class RoutingReceive {

    private static final String EXCHANGE_NAME = "logs";

    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();    // 连接工厂
        factory.setHost("localhost");
        Connection connection = factory.newConnection();        // 获取连接
        Channel channel = connection.createChannel();

        // 声明一个direct交换类型
        channel.exchangeDeclare(EXCHANGE_NAME, "direct");

        // 当声明队列，不加任何参数，产生的将是一个临时队列，getQueue返回的是队列名称
        String queueA = channel.queueDeclare().getQueue();
        String queueB = channel.queueDeclare().getQueue();
        System.out.println("临时队列：" + queueA);
        System.out.println("临时队列：" + queueB);

        // 第三个参数为“绑定建”
        channel.queueBind(queueA, EXCHANGE_NAME, "error");
        channel.queueBind(queueB, EXCHANGE_NAME, "info");
        channel.queueBind(queueB, EXCHANGE_NAME, "warning");

        Consumer consumerA = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String recv = new String(body, "UTF-8");
                System.out.println("Direct-Receive-A:" + recv);
            }
        };
        Consumer consumerB = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String recv = new String(body, "UTF-8");
                System.out.println("Direct-Receive-B:" + recv);
            }
        };
        channel.basicConsume(queueA, true, consumerA);
        channel.basicConsume(queueB, true, consumerB);
    }
}