This first part of the reference documentation is a high-level overview of Spring AMQP and the underlying concepts and some code snippets that will get you up and running as quickly as possible.
This is the 5 minute tour to get started with Spring AMQP.
Prerequisites: install and run the RabbitMQ broker (http://www.rabbitmq.com/download.html). Then grab the spring-rabbit JAR and all its dependencies - the easiest way to do that is to declare a dependency in your build tool, e.g. for Maven:
<dependency> <groupId>org.springframework.amqp</groupId> <artifactId>spring-rabbit</artifactId> <version>2.0.0.RC2</version> </dependency>
And for gradle:
compile 'org.springframework.amqp:spring-rabbit:2.0.0.RC2'
The minimum Spring Framework version dependency is 5.0.x.
The minimum amqp-client
java client library version is 4.1.0.
Note the this refers to the java client library; generally, it will work with older broker versions.
Using plain, imperative Java to send and receive a message:
ConnectionFactory connectionFactory = new CachingConnectionFactory(); AmqpAdmin admin = new RabbitAdmin(connectionFactory); admin.declareQueue(new Queue("myqueue")); AmqpTemplate template = new RabbitTemplate(connectionFactory); template.convertAndSend("myqueue", "foo"); String foo = (String) template.receiveAndConvert("myqueue");
Note that there is a ConnectionFactory
in the native Java Rabbit client as well.
We are using the Spring abstraction in the code above.
We are relying on the default exchange in the broker (since none is specified in the send), and the default binding of all queues to the default exchange by their name (hence we can use the queue name as a routing key in the send).
Those behaviours are defined in the AMQP specification.
The same example as above, but externalizing the resource configuration to XML:
ApplicationContext context = new GenericXmlApplicationContext("classpath:/rabbit-context.xml"); AmqpTemplate template = context.getBean(AmqpTemplate.class); template.convertAndSend("myqueue", "foo"); String foo = (String) template.receiveAndConvert("myqueue");
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:rabbit="http://www.springframework.org/schema/rabbit" xsi:schemaLocation="http://www.springframework.org/schema/rabbit http://www.springframework.org/schema/rabbit/spring-rabbit.xsd http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <rabbit:connection-factory id="connectionFactory"/> <rabbit:template id="amqpTemplate" connection-factory="connectionFactory"/> <rabbit:admin connection-factory="connectionFactory"/> <rabbit:queue name="myqueue"/> </beans>
The <rabbit:admin/>
declaration by default automatically looks for beans of type Queue
, Exchange
and Binding
and declares them to the broker on behalf of the user, hence there is no need to use that bean explicitly in the simple Java driver.
There are plenty of options to configure the properties of the components in the XML schema - you can use auto-complete features of your XML editor to explore them and look at their documentation.
The same example again with the external configuration in Java:
ApplicationContext context = new AnnotationConfigApplicationContext(RabbitConfiguration.class); AmqpTemplate template = context.getBean(AmqpTemplate.class); template.convertAndSend("myqueue", "foo"); String foo = (String) template.receiveAndConvert("myqueue"); ........ @Configuration public class RabbitConfiguration { @Bean public ConnectionFactory connectionFactory() { return new CachingConnectionFactory("localhost"); } @Bean public AmqpAdmin amqpAdmin() { return new RabbitAdmin(connectionFactory()); } @Bean public RabbitTemplate rabbitTemplate() { return new RabbitTemplate(connectionFactory()); } @Bean public Queue myQueue() { return new Queue("myqueue"); } }
Spring AMQP now uses the new 5.0.x version of the amqp-client
library provided by the RabbitMQ team.
This client has auto recovery configured by default; see the section called “RabbitMQ Automatic Connection/Topology recovery”.
Note | |
---|---|
As of version 4.0, the client enables automatic recovery by default; while compatible with this feature, Spring AMQP has its own recovery mechanisms and the client recovery feature generally isn’t needed.
It is recommended to disable |
The ExchangeBuilder
now builds durable exchanges by default.
The @Exchange
annotation used within a @QeueueBinding
also declares durable exchanges by default.
The @Queue
annotation used within a @RabbitListener
by default declares durable queues if named and non-durable if anonymous.
See the section called “Builder API for Queues and Exchanges” and the section called “Annotation-driven Listener Endpoints” for more information.
UniquelyNameQueue
is no longer provided. It is unusual to create a durable non auto-delete queue with a unique name.
This class has been deleted; if you require its functionality, use new Queue(UUID.randomUUID().toString())
.
The DirectMessageListenerContainer
has been added alongside the existing SimpleMessageListenerContainer
.
See the section called “Choosing a Container” and Section 3.1.15, “Message Listener Container Configuration” for information about choosing which container to use as well as how to configure them.
This appender is no longer available due to the end-of-life of log4j. See Section 3.2, “Logging Subsystem AMQP Appenders” for information about the available log appenders.
This appender no longer captures caller data (method, line number) by default; it can be re-enabled by setting the includeCallerData
configuration option.
See Section 3.2, “Logging Subsystem AMQP Appenders” for information about the available log appenders.
Important | |
---|---|
Previously, a non-transactional |
The RabbitTemplate
now uses a DirectReplyToMessageListenerContainer
(by default) instead of creating a new consumer for each request.
See the section called “RabbitMQ Direct reply-to” for more information.
The AsyncRabbitTemplate
now supports Direct reply-to; see the section called “AsyncRabbitTemplate” for more information.
The RabbitTemplate
and AsyncRabbitTemplate
now have receiveAndConvert
and convertSendAndReceiveAsType
methods that take a ParameterizedTypeReference<T>
argument, allowing the caller to specify the type to convert the result to.
This is particularly useful for complex types or when type information is not conveyed in message headers.
Requires a SmartMessageConverter
such as the Jackson2JsonMessageConverter
.
See Section 3.1.6, “Receiving messages”, Section 3.1.9, “Request/Reply Messaging”, the section called “AsyncRabbitTemplate”, and the section called “Converting From a Message With RabbitTemplate” for more information.
You can now use a RabbitTemplate
to perform multiple operations on a dedicated channel.
See the section called “Scoped Operations” for more information.
A convenient FunctionalInterface
is available for using lambdas with the MessageListenerAdapter
.
See the section called “MessageListenerAdapter” for more information.
The prefetch default value used to be 1, which could lead to under-utilization of efficient consumers. The default prefetch value is now 250, which should keep consumers busy in most common scenarios and thus improve throughput.
Important | |
---|---|
There are nevertheless scenarios where the prefetch value should be low: for example, with large messages, especially if the processing is slow (messages could add up to a large amount of memory in the client process), and if strict message ordering is necessary (the prefetch value should be set back to 1 in this case). Also, with low-volume messaging and multiple consumers (including concurrency within a single listener container instance), you may wish to reduce the prefetch to get a more even distribution of messages across consumers. |
For more background about prefetch, see this post about consumer utilization in RabbitMQ and this post about queuing theory.
Previously, MessageProperties.getMessageCount()
returned 0
for messages emitted by the container.
This property only applies when using basicGet
(e.g. from RabbitTemplate.receive()
methods) and is now initialized to null
for container messages.
Message requeue on transaction rollback is now consistent, regardless of whether or not a transaction manager is configured. See the section called “A note on Rollback of Received Messages” for more information.
If the container threads do not respond to a shutdown within shutdownTimeout
, the channel(s) will be forced closed, by default.
See Section 3.1.15, “Message Listener Container Configuration” for more information.
The connection and channel listener interfaces now provide a mechanism to obtain information about exceptions. See the section called “Connection and Channel Listeners” and the section called “Publishing is Asynchronous - How to Detect Success and Failures” for more information.
A new ConnectionNameStrategy
is now provided to populate the application-specific identification of the target RabbitMQ connection from the AbstractConnectionFactory
.
See Section 3.1.2, “Connection and Resource Management” for more information.
The MissingMessageIdAdvice
is no longer provided; it’s functionality is now built-in; see the section called “Failures in Synchronous Operations and Options for Retry” for more information.
By default, AnonymousQueues
are now named with the default Base64UrlNamingStrategy
instead of a simple UUID
string.
See the section called “AnonymousQueue” for more information.
You can now provide simple queue declarations (only bound to the default exchange) in @RabbitListener
annotations.
See the section called “Annotation-driven Listener Endpoints” for more information.
You can now configure @RabbitListener
annotations so that any exceptions thrown will be returned to the sender.
You can also configure a RabbitListenerErrorHandler
to handle exceptions.
See the section called “Handling Exceptions” for more information.
You can now bind a queue with multiple routing keys when using the @QueueBinding
annotation.
Also @QueueBinding.exchange()
now supports custom exchange types and declares durable exchanges by default.
You can now set the concurrency
of the listener container at the annotation level rather than having to configure a different container factory for different concurrency settings.
See the section called “Annotation-driven Listener Endpoints” for more information.
When using an external transaction manager (e.g. JDBC), rule-based rollback is now supported when providing the container with a transaction attribute. It is also now more flexible when using a transaction advice. See the section called “Conditional Rollback” for more information.
Deprecated in previous versions, Jackson 1.x
converters and related components have now been deleted; use similar components based on Jackson 2.x.
See the section called “Jackson2JsonMessageConverter” for more information.
When the __TypeId__
is set to Hashtable
for an inbound JSON message, the default conversion type is now LinkedHashMap
; previously it was Hashtable
.
To revert to a Hashtable
use setDefaultMapType
on the DefaultClassMapper
.
When parsing Queue
and Exchange
XML components, the parsers no longer register the name
attribute value as a bean alias if an id
attribute is present.
See the section called “A Note On "id" and "name" Attributes” for more information.
See Section A.2, “Previous Releases” for changes in previous versions.