Rabbitmq，接收来自客户端的消息

Question

I have a simple producer and receiver classes to work with rabbitmq

Producer:

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, BuiltinExchangeType.FANOUT);

    String message = getMessage(argv);

    channel.basicPublish(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));
    System.out.println(" [x] Sent '" + message + "'");

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

And receiver :

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, BuiltinExchangeType.FANOUT);
    String queueName = channel.queueDeclare().getQueue();
    channel.queueBind(queueName, EXCHANGE_NAME, "");

    System.out.println(" [*] Waiting for messages. To exit press CTRL+C");

    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(" [x] Received '" + message + "'");
      }
    };
    channel.basicConsume(queueName, true, consumer);
  }

The question is, is it possible for Producer to know is the Receiver took the message . For example:

 channel.sendAndReceiveMessage(EXCHANGE_NAME, "", null, message.getBytes("UTF-8"));
        System.out.println(" [x] Sent '" + message + "'");

Answer 1

Short answser: You don't have a direct way to let the producer know that the consumer acked the message Long one: The second parameter you're sending here: channel.basicConsume(queueName, true, consumer); is the auto-ack, setting it to false will force you to do a channel.basicAck(deliveryTag, false); to acknowledge receipt of the message (you can get the delivery tag from the envelope) or a Channel.basicNack to tell that something failed What does it mean? it means that if you don't ack the message, it'll return to the queue and wait to be consumed again, this way, you can ensure that all messages will be consumed.