RabbitMQ预取值

 

假设生产者发送 11.22.33.44.55.66.77 条消息， 我们可以指定消费者C1接受2条消息，消费者C2接受5条消息。

最后的结果是消息堆积在信道，是说堆积在信道中最多有几条

public class DirectSend {
    private static final String EXCHANGE_NAME = "test_exchange_direct";
    private static final String TASK_QUEUE_NAME = "task_queue_name";
 
    private static final boolean durable = false;
    public static void main(String[] argv) throws Exception {
        // 获取到连接以及mq通道
        Connection connection = ConnectionUtil.getConnection();
        Channel channel = connection.createChannel();
 
 
        channel.queueDeclare(TASK_QUEUE_NAME, durable, false, false, null);
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()){
            String message = scanner.next();
            //设置生产者发送消息为持久化消息（要求保存到磁盘上）保存在内存中
            channel.basicPublish("", TASK_QUEUE_NAME, MessageProperties.PERSISTENT_TEXT_PLAIN, message.getBytes("UTF-8"));
            System.out.println("生产者发出消息");
        }
        channel.close();
        connection.close();
    }
}

public class DirectRecv {
    private final static String QUEUE_NAME = "test_queue_direct_1";
 
    private final static String EXCHANGE_NAME = "test_exchange_direct";
    private static final String TASK_QUEUE_NAME = "task_queue_name";
 
    public static void main(String[] argv) throws Exception {
 
        // 获取到连接以及mq通道
        Connection connection = ConnectionUtil.getConnection();
        Channel channel = connection.createChannel();
 
        System.out.println("c1 等待接收消息处理时间较短");
 
        DeliverCallback deliverCallback = (consumerTag, message)->{
            try {
                Thread.sleep(1000L);
            }catch (Exception e){
                e.printStackTrace();
            }
 
            System.out.println("接收到的消息：" + new String(message.getBody(),"UTF-8"));
 
            //手动应答
            /**
             * 1、消息的标记 tag
             * 2、是否批量应答 false ： 不批量应答信道中的小， true：批量
             */
            channel.basicAck(message.getEnvelope().getDeliveryTag(), false);
        };
 
        // 这只不公平分发
        int prefetchCount = 2;//默认是1
        channel.basicQos(prefetchCount);
 
        //采用手动应答
        boolean autoAct = false;
        channel.basicConsume(TASK_QUEUE_NAME, autoAct,deliverCallback,(consumerTag -> {
            System.out.println(consumerTag + "消费者消息取消接口回调逻辑");
        }));
    }
}

public class DirectRecv2 {
    private final static String QUEUE_NAME = "test_queue_direct_1";
 
    private final static String EXCHANGE_NAME = "test_exchange_direct";
    private static final String TASK_QUEUE_NAME = "task_queue_name";
 
    public static void main(String[] argv) throws Exception {
 
        // 获取到连接以及mq通道
        Connection connection = ConnectionUtil.getConnection();
        Channel channel = connection.createChannel();
 
        System.out.println("c1 等待接收消息处理时间较短");
 
        DeliverCallback deliverCallback = (consumerTag, message)->{
            try {
                Thread.sleep(30000L);
            }catch (Exception e){
                e.printStackTrace();
            }
 
            System.out.println("接收到的消息：" + new String(message.getBody(),"UTF-8"));
 
            //手动应答
            /**
             * 1、消息的标记 tag
             * 2、是否批量应答 false ： 不批量应答信道中的小， true：批量
             */
            channel.basicAck(message.getEnvelope().getDeliveryTag(), false);
        };
 
        // 这只不公平分发
        int prefetchCount = 5;//默认是1
        channel.basicQos(prefetchCount);
 
        //采用手动应答
        boolean autoAct = false;
        channel.basicConsume(TASK_QUEUE_NAME, autoAct,deliverCallback,(consumerTag -> {
            System.out.println(consumerTag + "消费者消息取消接口回调逻辑");
        }));
 
    }
 
}

 所以执行的结果，我们需要看消费者2是否消费到了5条数据