https://www.cnblogs.com/piaolingzxh/p/5448927.html
1、Channel
1.1 channel.exchangeDeclare()：
type：有direct、fanout、topic三种
durable：true、false true：服务器重启会保留下来Exchange。警告：仅设置此选项，不代表消息持久化。即不保证重启后消息还在。原文：true if we are declaring a durable exchange (the exchange will survive a server restart)
autoDelete:true、false.true:当已经没有消费者时，服务器是否可以删除该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, booleandurable,boolean autoDelete,
Map arguments)throwsIOException;
1.2 chanel.basicQos()
prefetchSize：0
prefetchCount：会告诉RabbitMQ不要同时给一个消费者推送多于N个消息，即一旦有N个消息还没有ack，则该consumer将block掉，直到有消息ack
global：true\false 是否将上面设置应用于channel，简单点说，就是上面限制是channel级别的还是consumer级别
备注：据说prefetchSize 和global这两项，rabbitmq没有实现，暂且不研究
/** * 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
*/voidbasicQos(intprefetchSize,intprefetchCount,booleanglobal)throwsIOException;
1.3 channel.basicPublish()
routingKey：路由键，#匹配0个或多个单词，*匹配一个单词，在topic exchange做消息转发用
mandatory：true：如果exchange根据自身类型和消息routeKey无法找到一个符合条件的queue，那么会调用basic.return方法将消息返还给生产者。false：出现上述情形broker会直接将消息扔掉
immediate：true：如果exchange在将消息route到queue(s)时发现对应的queue上没有消费者，那么这条消息不会放入队列中。当与消息routeKey关联的所有queue(一个或多个)都没有消费者时，该消息会通过basic.return方法返还给生产者。
BasicProperties ：需要注意的是BasicProperties.deliveryMode，0:不持久化 1：持久化 这里指的是消息的持久化，配合channel(durable=true),queue(durable)可以实现，即使服务器宕机，消息仍然保留
简单来说：mandatory标志告诉服务器至少将该消息route到一个队列中，否则将消息返还给生产者；immediate标志告诉服务器如果该消息关联的queue上有消费者，则马上将消息投递给它，如果所有queue都没有消费者，直接把消息返还给生产者，不用将消息入队列等待消费者了。
/** * Publish a message.
*
* Publishing to a non-existent exchange will result in a channel-level
* protocol exception, which closes the channel.
*
* Invocations of Channel#basicPublish will eventually block if a
* resource-driven alarm is in effect.
*
* @see com.rabbitmq.client.AMQP.Basic.Publish
* @see Resource-driven alarms.
* @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
*/voidbasicPublish(String exchange, String routingKey,booleanmandatory,booleanimmediate, BasicProperties props,byte[] body)
throwsIOException;
1.4channel.basicAck();
deliveryTag:该消息的index
multiple：是否批量.true:将一次性ack所有小于deliveryTag的消息。
/** * 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
*/voidbasicAck(longdeliveryTag,booleanmultiple)throwsIOException;
1.5channel.basicNack(delivery.getEnvelope().getDeliveryTag(), false, true);
deliveryTag:该消息的index
multiple：是否批量.true:将一次性拒绝所有小于deliveryTag的消息。
requeue：被拒绝的是否重新入队列
/** * Reject one or several received messages.
*
* Supply the deliveryTag 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
*/voidbasicNack(longdeliveryTag,booleanmultiple,boolean requeue)
throwsIOException;
1.5channel.basicReject(delivery.getEnvelope().getDeliveryTag(), false);
deliveryTag:该消息的index
requeue：被拒绝的是否重新入队列
channel.basicNack 与 channel.basicReject 的区别在于basicNack可以拒绝多条消息，而basicReject一次只能拒绝一条消息
/** * 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
*/voidbasicReject(longdeliveryTag,booleanrequeue)throwsIOException;
1.6 channel.basicConsume(QUEUE_NAME, true, consumer);
autoAck：是否自动ack，如果不自动ack，需要使用channel.ack、channel.nack、channel.basicReject 进行消息应答
/** * 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, booleanautoAck, Consumer callback)throwsIOException;
1.7 chanel.exchangeBind()
channel.queueBind(queueName, EXCHANGE_NAME, bindingKey);
用于通过绑定bindingKey将queue到Exchange，之后便可以进行消息接收
/** * 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) throwsIOException;
1.8 channel.queueDeclare(QUEUE_NAME, false, false, false, null);
durable：true、false true：在服务器重启时，能够存活
exclusive ：是否为当前连接的专用队列，在连接断开后，会自动删除该队列，生产环境中应该很少用到吧。
autodelete：当没有任何消费者使用时，自动删除该队列。this means that the queue will be deleted when there are no more processes consuming messages from it.
/** * 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, booleandurable,booleanexclusive,boolean autoDelete,
Map arguments)throwsIOException;