Confirm确认消息

消息确认机制

1.消息的确认，是指生产者投递消息后，如果Broker接受到消息，则会给生产者一个应答。
2.生产者进行接受应答，用来确认这条消息是否正常的发送到Broker，这种方式也是消息的可靠性投递的核心保障。

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消息确认实现

1.在channel上开启确认模式：channel.confirmSelect()。
2.在channel上添加监听，addConfirmListener，监听成功和失败的返回结果。根据具体的结果对消息进行重新发送或记录日子等后续处理。

public class Producer {

    public static void main(String[] args) throws IOException, TimeoutException {

        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.6.99");
        factory.setPort(5672);
        factory.setVirtualHost("/");

        Connection connection = factory.newConnection();

        Channel channel = connection.createChannel();

        //指定消息的确认模式
        channel.confirmSelect();

        channel.basicPublish("exchange2","",null,"hello world".getBytes());

        //添加监听
        channel.addConfirmListener(new ConfirmListener() {
            @Override
            public void handleAck(long deliveryTag, boolean multiple) throws IOException {
                System.out.println("handleAck");
            }
            
            @Override
            public void handleNack(long deliveryTag, boolean multiple) throws IOException {
                System.out.println("handleNack");
            }
        });

    }
}

public class Consumer1 {

    public static void main(String[] args) throws IOException, TimeoutException, InterruptedException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("192.168.6.99");
        factory.setPort(5672);
        factory.setVirtualHost("/");

        Connection connection = factory.newConnection();

        Channel channel = connection.createChannel();

        channel.exchangeDeclare("exchange2","topic",true);
        channel.queueDeclare("queueName2", true, false, false, null);

        channel.queueBind("queueName2","exchange2","");

        QueueingConsumer queueingConsumer = new QueueingConsumer(channel);

        channel.basicConsume("queueName2",true,queueingConsumer);

        while (true){
            QueueingConsumer.Delivery delivery = queueingConsumer.nextDelivery();
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println(" Received '" + message + "'");
        }
    }
}