1、当信息在一个队列中变成死信时,可以重新发送到DLX,绑定DLX的队列称为rabbitmq。

也叫死信队列。

2、常用于订单超时自动取消,会议预订提前提醒等等。

实例

importpikaimportjsonimporttimecredentials=pika.PlainCredentials('admin','admin')#mq用户名和密码#虚拟队列需要指定参数virtual_host,如果是默认的可以不填。connection=pika.BlockingConnection(pika.ConnectionParameters(host='127.0.0.1',port=5672,credentials=credentials))channel=connection.channel()#声明消息队列,消息将在这个队列传递,如不存在,则创建queue_name="delay_queue_a"exchange='delay_exchange_a'routing_key='delay_routing_key_a'dead_letter_exchange='dead_exchange_a'#'amq.direct'#'dead_exchange_a'dead_letter_routing_key='dead_letter_routing_key_a'#'dead_queue_a'#'dead_letter_routing_key_a'arguments={"x-message-ttl":5000,'x-dead-letter-exchange':dead_letter_exchange,'x-dead-letter-routing-key':dead_letter_routing_key}channel.confirm_delivery()channel.exchange_declare(exchange=exchange,durable=True,exchange_type='direct')result=channel.queue_declare(queue=queue_name,durable=False,arguments=arguments)channel.queue_bind(exchange=exchange,queue=queue_name,routing_key=routing_key)foriinrange(10):message=json.dumps({'OrderId':i})#向队列插入数值routing_key是队列名channel.basic_publish(exchange=exchange,routing_key=routing_key,body=message,properties=pika.BasicProperties(delivery_mode=2))print(message)time.sleep(1.5)connection.close()