To download, install and run Redis please refer to the Redis documentation.

To begin interacting with Redis you first need to connect to it. Spring Integration uses support provided by another Spring project, Spring Data Redis, which provides typical Spring constructs: ConnectionFactory and Template. Those abstractions simplify integration with several Redis-client Java APIs. Currently Spring-Data-Redis supports jedis, jredis and rjc

RedisConnectionFactory

To connect to Redis you would use one of the implementations of the RedisConnectionFactory interface:

public interface RedisConnectionFactory extends PersistenceExceptionTranslator {

	/**
	 * Provides a suitable connection for interacting with Redis.
	 *
	 * @return connection for interacting with Redis.
	 */
	RedisConnection getConnection();
}

The example below shows how to create a JedisConnectionFactory.

In Java:

JedisConnectionFactory jcf = new JedisConnectionFactory();
jcf.afterPropertiesSet();

Or in Spring's XML configuration:

<bean id="redisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
	<property name="port" value="7379" />
</bean>

The implementations of RedisConnectionFactory provide a set of properties such as port and host that can be set if needed. Once an instance of RedisConnectionFactory is created, you can create an instance of RedisTemplate and inject it with the RedisConnectionFactory.

RedisTemplate

As with other template classes in Spring (e.g., JdbcTemplate, JmsTemplate) RedisTemplate is a helper class that simplifies Redis data access code. For more information about RedisTemplate and its variations (e.g., StringRedisTemplate) please refer to the Spring-Data-Redis documentation

The code below shows how to create an instance of RedisTemplate:

In Java:

RedisTemplate rt = new RedisTemplate<String, Object>();
rt.setConnectionFactory(redisConnectionFactory);

Or in Spring's XML configuration::

<bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate">
	<property name="connectionFactory" ref="redisConnectionFactory"/>
</bean>

As mentioned in the introduction Redis provides support for Publish-Subscribe messaging via its PUBLISH, SUBSCRIBE and UNSUBSCRIBE commands. As with JMS and AMQP, Spring Integration provides Message Channels and adapters for sending and receiving messages via Redis.

<int-redis:publish-subscribe-channel id="redisChannel" topic-name="si.test.topic"/>

<int-redis:inbound-channel-adapter id="redisAdapter"
       topics="foo, bar"
       channel="receiveChannel"
       error-channel="testErrorChannel"
       message-converter="testConverter" />

<bean id="redisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
    <property name="port" value="7379" />
</bean>

<bean id="testConverter" class="foo.bar.SampleMessageConverter" />

<int-redis:outbound-channel-adapter id="outboundAdapter"
			channel="sendChannel"
			topic="foo"
			message-converter="testConverter"/>

<bean id="redisConnectionFactory" class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory">
	<property name="port" value="7379"/>
</bean>

<bean id="testConverter" class="foo.bar.SampleMessageConverter" />

As described in EIP, a Message Store allows you to persist Messages. This can be very useful when dealing with components that have a capability to buffer messages (QueueChannel, Aggregator, Resequencer, etc.) if reliability is a concern. In Spring Integration, the MessageStore strategy also provides the foundation for the ClaimCheck pattern, which is described in EIP as well.

Spring Integration's Redis module provides the RedisMessageStore which is an implementation of both the the MessageStore strategy (mainly used by the QueueChannel and ClaimCheck patterns) and the MessageGroupStore strategy (mainly used by the Aggregator and Resequencer patterns).

<bean id="redisMessageStore" class="org.springframework.integration.redis.store.RedisMessageStore">
    <constructor-arg ref="redisConnectionFactory"/>
</bean>

<int:channel id="somePersistentQueueChannel">
    <int:queue message-store="redisMessageStore"/>
<int:channel>

<int:aggregator input-channel="inputChannel" output-channel="outputChannel"
         message-store="redisMessageStore"/>

Above is a sample RedisMessageStore configuration that shows its usage by a QueueChannel and an Aggregator. As you can see it is a simple bean configuration, and it expects a RedisConnectionFactory as a constructor argument.

By default the RedisMessageStore will use Java serialization to serialize the Message. However if you want to use a different serialization technique (e.g., JSON), you can provide your own serializer via the valueSerializer property of the RedisMessageStore.

The RedisStore Inbound Channel Adapter is a polling consumer that reads data from a Redis collection and sends it as a Message payload.

<int-redis:store-inbound-channel-adapter id="listAdapter"
		connection-factory="redisConnectionFactory"
		key="myCollection"
		channel="redisChannel"
		collection-type="LIST" >
			<int:poller fixed-rate="2000" max-messages-per-poll="10"/>
</int-redis:store-inbound-channel-adapter>

As you can see from the configuration above you configure a Redis Store Inbound Channel Adapter using the store-inbound-channel-adapter element, providing values for various attributes such as:

and other attributes that are common across all other inbound adapters (e.g., 'channel').

	Note
	You cannot set both redis-template and connection-factory.

Important

By default, the adapter uses a StringRedisTemplate; this uses StringRedisSerializers for keys, values, hash keys and hash values. If your Redis store contains objects that are serialized with other techniques, you must supply a RedisTemplate configured with appropriate serializers. For example, if the store is written to using a RedisStore Outbound Adapter that has its extract-payload-elements set to false, you must provide a RedisTemplate configured thus: <bean id="redisTemplate" class="org.springframework.data.redis.core.RedisTemplate"> <property name="connectionFactory" ref="redisConnectionFactory"/> <property name="keySerializer"> <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/> </property> <property name="hashKeySerializer"> <bean class="org.springframework.data.redis.serializer.StringRedisSerializer"/> </property> </bean> This uses String serializers for keys and hash keys and the default JDK Serialization serializers for values and hash values.

The example above is relatively simple and static since it has a literal value for the key. Sometimes, you may need to change the value of the key at runtime based on some condition. To do that, simply use key-expression instead, where the provided expression can be any valid SpEL expression.

Also, you may wish to perform some post-processing to the successfully processed data that was read from the Redis collection. For example; you may want to move or remove the value after its been processed. You can do this using the Transaction Synchronization feature that was added with Spring Integration 2.2.

<int-redis:store-inbound-channel-adapter id="zsetAdapterWithSingleScoreAndSynchronization"
        connection-factory="redisConnectionFactory"
        key-expression="'presidents'"
        channel="otherRedisChannel"
        auto-startup="false"
        collection-type="ZSET">
            <int:poller fixed-rate="1000" max-messages-per-poll="2">
                <int:transactional synchronization-factory="syncFactory"/>
            </int:poller>
</int-redis:store-inbound-channel-adapter>

<int:transaction-synchronization-factory id="syncFactory">
	<int:after-commit expression="payload.removeByScore(18, 18)"/>
</int:transaction-synchronization-factory>

<bean id="transactionManager" class="org.springframework.integration.transaction.PseudoTransactionManager"/>

As you can see from the above all, you need to do is declare your poller to be transactional with a transactional element. This element can reference a real transaction manager (for example if some other part of your flow invokes JDBC). If you don't have a 'real' transaction, you can use a org.springframework.integration.transaction.PseudoTransactionManager which is an implementation of Spring's PlatformTransactionManager and enables the use of the transaction synchronization features of the redis adapter when there is no actual transaction.

	Important
	This does NOT make the Redis activities themselves transactional, it simply allows the synchronization of actions to be taken before/after success (commit) or after failure (rollback).

Once your poller is transactional all you need to do is set an instance of the org.springframework.integration.transaction.TransactionSynchronizationFactory on the transactional element. TransactionSynchronizationFactory will create an instance of the TransactionSynchronization. For your convenience we've exposed a default SpEL-based TransactionSynchronizationFactory which allows you to configure SpEL expressions, with their execution being coordinated (synchronized) with a transaction. Expressions for before-commit, after-commit, and after-rollback are supported, together with a channel for each where the evaluation result (if any) will be sent. For each sub-element you can specify expression and/or channel attributes. If only the channel attribute is present the received Message will be sent there as part of the particular synchronization scenario. If only the expression attribute is present and the result of an expression is a non-Null value, a Message with the result as the payload will be generated and sent to a default channel (NullChannel) and will appear in the logs (DEBUG). If you want the evaluation result to go to a specific channel add a channel attribute. If the result of an expression is null or void, no Message will be generated.

For more information about transaction synchronization, see Section B.3, “Transaction Synchronization”.

The RedisStore Outbound Channel Adapter allows you to write a Message payload to a Redis collection

<int-redis:store-outbound-channel-adapter id="redisListAdapter"
          collection-type="LIST"
          channel="requestChannel"
          key="myCollection" />

As you can see from the configuration above, you configure a Redis Store Outbound Channel Adapter using the store-inbound-channel-adapter element, providing values for various attributes such as:

and other attributes that are common across all other inbound adapters (e.g., 'channel').

	Note
	You cannot set both redis-template and connection-factory.

Important

By default, the adapter uses a StringRedisTemplate; this uses StringRedisSerializers for keys, values, hash keys and hash values. However, if extract-payload-elements is set to false, a RedisTemplate using StringRedisSerializers for keys and hash keys, and JdkSerializationRedisSerializers for values and hash values will be used. With the JDK serializer, it is important to understand that java serialization is used for all values, regardless of whether the value is actually a collection or not. If you need more control over the serialization of values, you may want to consider providing your own RedisTemplate rather than relying upon these defaults.

The example above is relatively simple and static since it has a literal values for the key and other attributes. Sometimes you may need to change the values dynamically at runtime based on some condition. To do that simply use their -expression equivalents (key-expression, map-key-expression etc.) where the provided expression can be any valid SpEL expression.