WorkQueues（工作队列），在工作线程之间分配任务

生产者

package org.example.workqueue;

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

import java.nio.charset.StandardCharsets;

public class NewTask {

    private static final String TASK_QUEUE_NAME = "task_queue";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.121.200");
        try (Connection connection = factory.newConnection(); Channel channel = connection.createChannel()) {
            channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);

            for (int i = 0; i < 10; i++) {
                String message = "消息：" + i;

                channel.basicPublish("", TASK_QUEUE_NAME, MessageProperties.PERSISTENT_TEXT_PLAIN, message.getBytes(StandardCharsets.UTF_8));
                System.out.println(" [生产者] Sent '" + message + "'");
            }

        }
    }
}

消费者1

package org.example.workqueue;

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

public class Worker1 {
    private static final String TASK_QUEUE_NAME = "task_queue";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.121.200");
        final Connection connection = factory.newConnection();
        final Channel channel = connection.createChannel();

        channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);
        System.out.println(" [工作者1] Waiting for messages. To exit press CTRL+C");

        //如果不写basicQos（1），则自动MQ会将所有请求平均发送给所有消费者
        //basicQos,MQ不再对消费者一次发送多个请求，而是消费者处理完一个消息后（确认后），在从队列中获取一个新的
        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");

            System.out.println(" [工作者1] Received '" + message + "'");
            try {
                doWork(message);
            } finally {
                System.out.println(" [工作者1] Done");
                channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
            }
        };
        channel.basicConsume(TASK_QUEUE_NAME, false, deliverCallback, consumerTag -> {
        });
    }

    private static void doWork(String task) {
        try {
            Thread.sleep(1000);
        } catch (InterruptedException _ignored) {
            Thread.currentThread().interrupt();
        }
    }
}

消费者2

package org.example.workqueue;

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

public class Worker2 {
    private static final String TASK_QUEUE_NAME = "task_queue";

    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.121.200");
        final Connection connection = factory.newConnection();
        final Channel channel = connection.createChannel();

        channel.queueDeclare(TASK_QUEUE_NAME, true, false, false, null);
        System.out.println(" [工作者2] Waiting for messages. To exit press CTRL+C");

        channel.basicQos(1);

        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");

            System.out.println(" [工作者2] Received '" + message + "'");
            try {
                doWork(message);
            } finally {
                System.out.println(" [工作者2] Done");
                channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
            }
        };
        channel.basicConsume(TASK_QUEUE_NAME, false, deliverCallback, consumerTag -> {
        });
    }

    private static void doWork(String task) {

        try {
            Thread.sleep(500);
        } catch (InterruptedException _ignored) {
            Thread.currentThread().interrupt();
        }
    }

}