Return消息机制

Return消息机制

• Return Listener用于处理一些不可路由的消息
• 我们的消息生产者，通过指定一个Exchange和Routingkey，把消息送达到某一个队列中去，然后我们的消费者监听队列，进行消费处理操作。

• 某些情况下Exchange不存在或路由key路由不到，这时我们就需要监听这个不可达的消息，就要用return listener

  
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  Producer

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();

        /**
         * mandatory需要设置为true，监听器会接受到路由不可达的消息，然后进行处理
         * 如果为false，则broker端自动删除该消息
         */
        channel.basicPublish("exchange2","return.error",true,null,"hello world".getBytes());

        channel.addReturnListener(new ReturnListener() {
            @Override
            public void handleReturn(int replyCode, String replyText, String exchange, String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {
                System.out.println("handleReturn");
                System.out.println("replyCode "+replyCode);
                System.out.println("replyText "+replyText);
                System.out.println("body "+new String(body));
            }
        });
    }
}

Consumer

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","return.key");

        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 + "'");
        }
    }
}