rabbitmq channel參數詳解【轉】

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1、Channel 

1.1 channel.exchangeDeclare()：

type：有direct、fanout、topic三種
durable：true、false true：服務器重啟會保留下來Exchange。警告：僅設置此選項，不代表消息持久化。即不保證重啟后消息還在。原文：true if we are declaring a durable exchange (the exchange will survive a server restart)
autoDelete:true、false.true:當已經沒有消費者時，服務器是否可以刪除該Exchange。原文1：true if the server should delete the exchange when it is no longer in use。

 /*** Declare an exchange.* @see com.rabbitmq.client.AMQP.Exchange.Declare* @see com.rabbitmq.client.AMQP.Exchange.DeclareOk* @param exchange the name of the exchange* @param type the exchange type* @param durable true if we are declaring a durable exchange (the exchange will survive a server restart)* @param autoDelete true if the server should delete the exchange when it is no longer in use* @param arguments other properties (construction arguments) for the exchange* @return a declaration-confirm method to indicate the exchange was successfully declared* @throws java.io.IOException if an error is encountered*/Exchange.DeclareOk exchangeDeclare(String exchange, String type, boolean durable, boolean autoDelete,Map<String, Object> arguments) throws IOException;

1.2 chanel.basicQos()

prefetchSize：0 
prefetchCount：會告訴RabbitMQ不要同時給一個消費者推送多于N個消息，即一旦有N個消息還沒有ack，則該consumer將block掉，直到有消息ack
global：true\false 是否將上面設置應用于channel，簡單點說，就是上面限制是channel級別的還是consumer級別

備注：據說prefetchSize 和global這兩項，rabbitmq沒有實現，暫且不研究

    /*** Request specific "quality of service" settings.** These settings impose limits on the amount of data the server* will deliver to consumers before requiring acknowledgements.* Thus they provide a means of consumer-initiated flow control.* @see com.rabbitmq.client.AMQP.Basic.Qos* @param prefetchSize maximum amount of content (measured in* octets) that the server will deliver, 0 if unlimited* @param prefetchCount maximum number of messages that the server* will deliver, 0 if unlimited* @param global true if the settings should be applied to the* entire channel rather than each consumer* @throws java.io.IOException if an error is encountered*/void basicQos(int prefetchSize, int prefetchCount, boolean global) throws IOException;

1.3 channel.basicPublish()

routingKey：路由鍵，#匹配0個或多個單詞，*匹配一個單詞，在topic exchange做消息轉發用

mandatory：true：如果exchange根據自身類型和消息routeKey無法找到一個符合條件的queue，那么會調用basic.return方法將消息返還給生產者。false：出現上述情形broker會直接將消息扔掉

immediate：true：如果exchange在將消息route到queue(s)時發現對應的queue上沒有消費者，那么這條消息不會放入隊列中。當與消息routeKey關聯的所有queue(一個或多個)都沒有消費者時，該消息會通過basic.return方法返還給生產者。
BasicProperties ：需要注意的是BasicProperties.deliveryMode，0:不持久化 1：持久化 這里指的是消息的持久化，配合channel(durable=true),queue(durable)可以實現，即使服務器宕機，消息仍然保留
簡單來說：mandatory標志告訴服務器至少將該消息route到一個隊列中，否則將消息返還給生產者；immediate標志告訴服務器如果該消息關聯的queue上有消費者，則馬上將消息投遞給它，如果所有queue都沒有消費者，直接把消息返還給生產者，不用將消息入隊列等待消費者了。

  /*** Publish a message.** Publishing to a non-existent exchange will result in a channel-level* protocol exception, which closes the channel.** Invocations of <code>Channel#basicPublish</code> will eventually block if a* <a href="http://www.rabbitmq.com/alarms.html">resource-driven alarm</a> is in effect.** @see com.rabbitmq.client.AMQP.Basic.Publish* @see <a href="http://www.rabbitmq.com/alarms.html">Resource-driven alarms</a>.* @param exchange the exchange to publish the message to* @param routingKey the routing key* @param mandatory true if the 'mandatory' flag is to be set* @param immediate true if the 'immediate' flag is to be* set. Note that the RabbitMQ server does not support this flag.* @param props other properties for the message - routing headers etc* @param body the message body* @throws java.io.IOException if an error is encountered*/void basicPublish(String exchange, String routingKey, boolean mandatory, boolean immediate, BasicProperties props, byte[] body)throws IOException;

1.4?channel.basicAck();

deliveryTag:該消息的index
multiple：是否批量.true:將一次性ack所有小于deliveryTag的消息。

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    /*** Acknowledge one or several received* messages. Supply the deliveryTag from the {@link com.rabbitmq.client.AMQP.Basic.GetOk}* or {@link com.rabbitmq.client.AMQP.Basic.Deliver} method* containing the received message being acknowledged.* @see com.rabbitmq.client.AMQP.Basic.Ack* @param deliveryTag the tag from the received {@link com.rabbitmq.client.AMQP.Basic.GetOk} or {@link com.rabbitmq.client.AMQP.Basic.Deliver}* @param multiple true to acknowledge all messages up to and* including the supplied delivery tag; false to acknowledge just* the supplied delivery tag.* @throws java.io.IOException if an error is encountered*/void basicAck(long deliveryTag, boolean multiple) throws IOException;

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1.5?channel.basicNack(delivery.getEnvelope().getDeliveryTag(),?false,?true);

deliveryTag:該消息的index
multiple：是否批量.true:將一次性拒絕所有小于deliveryTag的消息。
requeue：被拒絕的是否重新入隊列

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    /*** Reject one or several received messages.** Supply the <code>deliveryTag</code> from the {@link com.rabbitmq.client.AMQP.Basic.GetOk}* or {@link com.rabbitmq.client.AMQP.Basic.GetOk} method containing the message to be rejected.* @see com.rabbitmq.client.AMQP.Basic.Nack* @param deliveryTag the tag from the received {@link com.rabbitmq.client.AMQP.Basic.GetOk} or {@link com.rabbitmq.client.AMQP.Basic.Deliver}* @param multiple true to reject all messages up to and including* the supplied delivery tag; false to reject just the supplied* delivery tag.* @param requeue true if the rejected message(s) should be requeued rather* than discarded/dead-lettered* @throws java.io.IOException if an error is encountered*/void basicNack(long deliveryTag, boolean multiple, boolean requeue)throws IOException;

1.5?channel.basicReject(delivery.getEnvelope().getDeliveryTag(),?false);

deliveryTag:該消息的index
requeue：被拒絕的是否重新入隊列

channel.basicNack 與?channel.basicReject 的區別在于basicNack可以拒絕多條消息，而basicReject一次只能拒絕一條消息

 /*** Reject a message. Supply the deliveryTag from the {@link com.rabbitmq.client.AMQP.Basic.GetOk}* or {@link com.rabbitmq.client.AMQP.Basic.Deliver} method* containing the received message being rejected.* @see com.rabbitmq.client.AMQP.Basic.Reject* @param deliveryTag the tag from the received {@link com.rabbitmq.client.AMQP.Basic.GetOk} or {@link com.rabbitmq.client.AMQP.Basic.Deliver}* @param requeue true if the rejected message should be requeued rather than discarded/dead-lettered* @throws java.io.IOException if an error is encountered*/void basicReject(long deliveryTag, boolean requeue) throws IOException;

1.6 channel.basicConsume(QUEUE_NAME, true, consumer);

autoAck：是否自動ack，如果不自動ack，需要使用channel.ack、channel.nack、channel.basicReject 進行消息應答

    /*** Start a non-nolocal, non-exclusive consumer, with* a server-generated consumerTag.* @param queue the name of the queue* @param autoAck true if the server should consider messages* acknowledged once delivered; false if the server should expect* explicit acknowledgements* @param callback an interface to the consumer object* @return the consumerTag generated by the server* @throws java.io.IOException if an error is encountered* @see com.rabbitmq.client.AMQP.Basic.Consume* @see com.rabbitmq.client.AMQP.Basic.ConsumeOk* @see #basicConsume(String, boolean, String, boolean, boolean, Map, Consumer)*/String basicConsume(String queue, boolean autoAck, Consumer callback) throws IOException;

1.7 chanel.exchangeBind()

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channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);
用于通過綁定bindingKey將queue到Exchange，之后便可以進行消息接收

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    /*** Bind an exchange to an exchange, with no extra arguments.* @see com.rabbitmq.client.AMQP.Exchange.Bind* @see com.rabbitmq.client.AMQP.Exchange.BindOk* @param destination the name of the exchange to which messages flow across the binding* @param source the name of the exchange from which messages flow across the binding* @param routingKey the routine key to use for the binding* @return a binding-confirm method if the binding was successfully created* @throws java.io.IOException if an error is encountered*/Exchange.BindOk exchangeBind(String destination, String source, String routingKey) throws IOException;

1.8?channel.queueDeclare(QUEUE_NAME, false, false, false, null);

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durable：true、false true：在服務器重啟時，能夠存活

exclusive ：是否為當前連接的專用隊列，在連接斷開后，會自動刪除該隊列，生產環境中應該很少用到吧。
autodelete：當沒有任何消費者使用時，自動刪除該隊列。this means that the queue will be deleted when there are no more processes consuming messages from it.

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 /*** Declare a queue* @see com.rabbitmq.client.AMQP.Queue.Declare* @see com.rabbitmq.client.AMQP.Queue.DeclareOk* @param queue the name of the queue* @param durable true if we are declaring a durable queue (the queue will survive a server restart)* @param exclusive true if we are declaring an exclusive queue (restricted to this connection)* @param autoDelete true if we are declaring an autodelete queue (server will delete it when no longer in use)* @param arguments other properties (construction arguments) for the queue* @return a declaration-confirm method to indicate the queue was successfully declared* @throws java.io.IOException if an error is encountered*/Queue.DeclareOk queueDeclare(String queue, boolean durable, boolean exclusive, boolean autoDelete,Map<String, Object> arguments) throws IOException;

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轉：https://www.cnblogs.com/piaolingzxh/p/5448927.html

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