Caching

The Spring Framework provides support for transparently adding caching to an application. At its core, the abstraction applies caching to methods, thus reducing the number of executions based on the information available in the cache. The caching logic is applied transparently, without any interference to the invoker. Spring Boot auto-configures the cache infrastructure as long as caching support is enabled by using the @EnableCaching annotation.

Check the relevant section of the Spring Framework reference for more details.

In a nutshell, to add caching to an operation of your service add the relevant annotation to its method, as shown in the following example:

  • Java

  • Kotlin

import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Component;

@Component
public class MyMathService {

	@Cacheable("piDecimals")
	public int computePiDecimal(int precision) {
		...
	}

}
import org.springframework.cache.annotation.Cacheable
import org.springframework.stereotype.Component

@Component
class MyMathService {

	@Cacheable("piDecimals")
	fun computePiDecimal(precision: Int): Int {
		...
	}

}

This example demonstrates the use of caching on a potentially costly operation. Before invoking computePiDecimal, the abstraction looks for an entry in the piDecimals cache that matches the i argument. If an entry is found, the content in the cache is immediately returned to the caller, and the method is not invoked. Otherwise, the method is invoked, and the cache is updated before returning the value.

You can also use the standard JSR-107 (JCache) annotations (such as @CacheResult) transparently. However, we strongly advise you to not mix and match the Spring Cache and JCache annotations.

If you do not add any specific cache library, Spring Boot auto-configures a simple provider that uses concurrent maps in memory. When a cache is required (such as piDecimals in the preceding example), this provider creates it for you. The simple provider is not really recommended for production usage, but it is great for getting started and making sure that you understand the features. When you have made up your mind about the cache provider to use, please make sure to read its documentation to figure out how to configure the caches that your application uses. Nearly all providers require you to explicitly configure every cache that you use in the application. Some offer a way to customize the default caches defined by the spring.cache.cache-names property.

It is also possible to transparently update or evict data from the cache.

Supported Cache Providers

The cache abstraction does not provide an actual store and relies on abstraction materialized by the org.springframework.cache.Cache and org.springframework.cache.CacheManager interfaces.

If you have not defined a bean of type CacheManager or a CacheResolver named cacheResolver (see CachingConfigurer), Spring Boot tries to detect the following providers (in the indicated order):

  1. Generic

  2. JCache (JSR-107) (EhCache 3, Hazelcast, Infinispan, and others)

  3. Hazelcast

  4. Infinispan

  5. Couchbase

  6. Redis

  7. Caffeine

  8. Cache2k

  9. Simple

Additionally, Spring Boot for Apache Geode provides auto-configuration for using Apache Geode as a cache provider.

If the CacheManager is auto-configured by Spring Boot, it is possible to force a particular cache provider by setting the spring.cache.type property. Use this property if you need to use no-op caches in certain environments (such as tests).
Use the spring-boot-starter-cache “Starter” to quickly add basic caching dependencies. The starter brings in spring-context-support. If you add dependencies manually, you must include spring-context-support in order to use the JCache or Caffeine support.

If the CacheManager is auto-configured by Spring Boot, you can further tune its configuration before it is fully initialized by exposing a bean that implements the CacheManagerCustomizer interface. The following example sets a flag to say that null values should not be passed down to the underlying map:

  • Java

  • Kotlin

import org.springframework.boot.autoconfigure.cache.CacheManagerCustomizer;
import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration(proxyBeanMethods = false)
public class MyCacheManagerConfiguration {

	@Bean
	public CacheManagerCustomizer<ConcurrentMapCacheManager> cacheManagerCustomizer() {
		return (cacheManager) -> cacheManager.setAllowNullValues(false);
	}

}
import org.springframework.boot.autoconfigure.cache.CacheManagerCustomizer
import org.springframework.cache.concurrent.ConcurrentMapCacheManager
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration

@Configuration(proxyBeanMethods = false)
class MyCacheManagerConfiguration {

	@Bean
	fun cacheManagerCustomizer(): CacheManagerCustomizer<ConcurrentMapCacheManager> {
		return CacheManagerCustomizer { cacheManager ->
			cacheManager.isAllowNullValues = false
		}
	}

}
In the preceding example, an auto-configured ConcurrentMapCacheManager is expected. If that is not the case (either you provided your own config or a different cache provider was auto-configured), the customizer is not invoked at all. You can have as many customizers as you want, and you can also order them by using @Order or Ordered.

Generic

Generic caching is used if the context defines at least one org.springframework.cache.Cache bean. A CacheManager wrapping all beans of that type is created.

JCache (JSR-107)

JCache is bootstrapped through the presence of a javax.cache.spi.CachingProvider on the classpath (that is, a JSR-107 compliant caching library exists on the classpath), and the JCacheCacheManager is provided by the spring-boot-starter-cache “Starter”. Various compliant libraries are available, and Spring Boot provides dependency management for Ehcache 3, Hazelcast, and Infinispan. Any other compliant library can be added as well.

It might happen that more than one provider is present, in which case the provider must be explicitly specified. Even if the JSR-107 standard does not enforce a standardized way to define the location of the configuration file, Spring Boot does its best to accommodate setting a cache with implementation details, as shown in the following example:

  • Properties

  • YAML

spring.cache.jcache.provider=com.example.MyCachingProvider
spring.cache.jcache.config=classpath:example.xml
# Only necessary if more than one provider is present
spring:
  cache:
    jcache:
      provider: "com.example.MyCachingProvider"
      config: "classpath:example.xml"
When a cache library offers both a native implementation and JSR-107 support, Spring Boot prefers the JSR-107 support, so that the same features are available if you switch to a different JSR-107 implementation.
Spring Boot has general support for Hazelcast. If a single HazelcastInstance is available, it is automatically reused for the CacheManager as well, unless the spring.cache.jcache.config property is specified.

There are two ways to customize the underlying javax.cache.cacheManager:

  • Caches can be created on startup by setting the spring.cache.cache-names property. If a custom javax.cache.configuration.Configuration bean is defined, it is used to customize them.

  • org.springframework.boot.autoconfigure.cache.JCacheManagerCustomizer beans are invoked with the reference of the CacheManager for full customization.

If a standard javax.cache.CacheManager bean is defined, it is wrapped automatically in an org.springframework.cache.CacheManager implementation that the abstraction expects. No further customization is applied to it.

Hazelcast

Spring Boot has general support for Hazelcast. If a HazelcastInstance has been auto-configured and com.hazelcast:hazelcast-spring is on the classpath, it is automatically wrapped in a CacheManager.

Hazelcast can be used as a JCache compliant cache or as a Spring CacheManager compliant cache. When setting spring.cache.type to hazelcast, Spring Boot will use the CacheManager based implementation. If you want to use Hazelcast as a JCache compliant cache, set spring.cache.type to jcache. If you have multiple JCache compliant cache providers and want to force the use of Hazelcast, you have to explicitly set the JCache provider.

Infinispan

Infinispan has no default configuration file location, so it must be specified explicitly. Otherwise, the default bootstrap is used.

  • Properties

  • YAML

spring.cache.infinispan.config=infinispan.xml
spring:
  cache:
    infinispan:
      config: "infinispan.xml"

Caches can be created on startup by setting the spring.cache.cache-names property. If a custom ConfigurationBuilder bean is defined, it is used to customize the caches.

To be compatible with Spring Boot’s Jakarta EE 9 baseline, Infinispan’s -jakarta modules must be used. For every module with a -jakarta variant, the variant must be used in place of the standard module. For example, infinispan-core-jakarta and infinispan-commons-jakarta must be used in place of infinispan-core and infinispan-commons respectively.

Couchbase

If Spring Data Couchbase is available and Couchbase is configured, a CouchbaseCacheManager is auto-configured. It is possible to create additional caches on startup by setting the spring.cache.cache-names property and cache defaults can be configured by using spring.cache.couchbase.* properties. For instance, the following configuration creates cache1 and cache2 caches with an entry expiration of 10 minutes:

  • Properties

  • YAML

spring.cache.cache-names=cache1,cache2
spring.cache.couchbase.expiration=10m
spring:
  cache:
    cache-names: "cache1,cache2"
    couchbase:
      expiration: "10m"

If you need more control over the configuration, consider registering a CouchbaseCacheManagerBuilderCustomizer bean. The following example shows a customizer that configures a specific entry expiration for cache1 and cache2:

  • Java

  • Kotlin

import java.time.Duration;

import org.springframework.boot.autoconfigure.cache.CouchbaseCacheManagerBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.couchbase.cache.CouchbaseCacheConfiguration;

@Configuration(proxyBeanMethods = false)
public class MyCouchbaseCacheManagerConfiguration {

	@Bean
	public CouchbaseCacheManagerBuilderCustomizer myCouchbaseCacheManagerBuilderCustomizer() {
		return (builder) -> builder
				.withCacheConfiguration("cache1", CouchbaseCacheConfiguration
						.defaultCacheConfig().entryExpiry(Duration.ofSeconds(10)))
				.withCacheConfiguration("cache2", CouchbaseCacheConfiguration
						.defaultCacheConfig().entryExpiry(Duration.ofMinutes(1)));

	}

}
import org.springframework.boot.autoconfigure.cache.CouchbaseCacheManagerBuilderCustomizer
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.data.couchbase.cache.CouchbaseCacheConfiguration
import java.time.Duration

@Configuration(proxyBeanMethods = false)
class MyCouchbaseCacheManagerConfiguration {

	@Bean
	fun myCouchbaseCacheManagerBuilderCustomizer(): CouchbaseCacheManagerBuilderCustomizer {
		return CouchbaseCacheManagerBuilderCustomizer { builder ->
			builder
				.withCacheConfiguration(
					"cache1", CouchbaseCacheConfiguration
						.defaultCacheConfig().entryExpiry(Duration.ofSeconds(10))
				)
				.withCacheConfiguration(
					"cache2", CouchbaseCacheConfiguration
						.defaultCacheConfig().entryExpiry(Duration.ofMinutes(1))
				)
		}
	}

}

Redis

If Redis is available and configured, a RedisCacheManager is auto-configured. It is possible to create additional caches on startup by setting the spring.cache.cache-names property and cache defaults can be configured by using spring.cache.redis.* properties. For instance, the following configuration creates cache1 and cache2 caches with a time to live of 10 minutes:

  • Properties

  • YAML

spring.cache.cache-names=cache1,cache2
spring.cache.redis.time-to-live=10m
spring:
  cache:
    cache-names: "cache1,cache2"
    redis:
      time-to-live: "10m"
By default, a key prefix is added so that, if two separate caches use the same key, Redis does not have overlapping keys and cannot return invalid values. We strongly recommend keeping this setting enabled if you create your own RedisCacheManager.
You can take full control of the default configuration by adding a RedisCacheConfiguration @Bean of your own. This can be useful if you need to customize the default serialization strategy.

If you need more control over the configuration, consider registering a RedisCacheManagerBuilderCustomizer bean. The following example shows a customizer that configures a specific time to live for cache1 and cache2:

  • Java

  • Kotlin

import java.time.Duration;

import org.springframework.boot.autoconfigure.cache.RedisCacheManagerBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;

@Configuration(proxyBeanMethods = false)
public class MyRedisCacheManagerConfiguration {

	@Bean
	public RedisCacheManagerBuilderCustomizer myRedisCacheManagerBuilderCustomizer() {
		return (builder) -> builder
				.withCacheConfiguration("cache1", RedisCacheConfiguration
						.defaultCacheConfig().entryTtl(Duration.ofSeconds(10)))
				.withCacheConfiguration("cache2", RedisCacheConfiguration
						.defaultCacheConfig().entryTtl(Duration.ofMinutes(1)));

	}

}
import org.springframework.boot.autoconfigure.cache.RedisCacheManagerBuilderCustomizer
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import org.springframework.data.redis.cache.RedisCacheConfiguration
import java.time.Duration

@Configuration(proxyBeanMethods = false)
class MyRedisCacheManagerConfiguration {

	@Bean
	fun myRedisCacheManagerBuilderCustomizer(): RedisCacheManagerBuilderCustomizer {
		return RedisCacheManagerBuilderCustomizer { builder ->
			builder
				.withCacheConfiguration(
					"cache1", RedisCacheConfiguration
						.defaultCacheConfig().entryTtl(Duration.ofSeconds(10))
				)
				.withCacheConfiguration(
					"cache2", RedisCacheConfiguration
						.defaultCacheConfig().entryTtl(Duration.ofMinutes(1))
				)
		}
	}

}

Caffeine

Caffeine is a Java 8 rewrite of Guava’s cache that supersedes support for Guava. If Caffeine is present, a CaffeineCacheManager (provided by the spring-boot-starter-cache “Starter”) is auto-configured. Caches can be created on startup by setting the spring.cache.cache-names property and can be customized by one of the following (in the indicated order):

  1. A cache spec defined by spring.cache.caffeine.spec

  2. A com.github.benmanes.caffeine.cache.CaffeineSpec bean is defined

  3. A com.github.benmanes.caffeine.cache.Caffeine bean is defined

For instance, the following configuration creates cache1 and cache2 caches with a maximum size of 500 and a time to live of 10 minutes

  • Properties

  • YAML

spring.cache.cache-names=cache1,cache2
spring.cache.caffeine.spec=maximumSize=500,expireAfterAccess=600s
spring:
  cache:
    cache-names: "cache1,cache2"
    caffeine:
      spec: "maximumSize=500,expireAfterAccess=600s"

If a com.github.benmanes.caffeine.cache.CacheLoader bean is defined, it is automatically associated to the CaffeineCacheManager. Since the CacheLoader is going to be associated with all caches managed by the cache manager, it must be defined as CacheLoader<Object, Object>. The auto-configuration ignores any other generic type.

Cache2k

Cache2k is an in-memory cache. If the Cache2k spring integration is present, a SpringCache2kCacheManager is auto-configured.

Caches can be created on startup by setting the spring.cache.cache-names property. Cache defaults can be customized using a Cache2kBuilderCustomizer bean. The following example shows a customizer that configures the capacity of the cache to 200 entries, with an expiration of 5 minutes:

  • Java

  • Kotlin

import java.util.concurrent.TimeUnit;

import org.springframework.boot.autoconfigure.cache.Cache2kBuilderCustomizer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration(proxyBeanMethods = false)
public class MyCache2kDefaultsConfiguration {

	@Bean
	public Cache2kBuilderCustomizer myCache2kDefaultsCustomizer() {
		return (builder) -> builder.entryCapacity(200)
				.expireAfterWrite(5, TimeUnit.MINUTES);
	}

}
import org.springframework.boot.autoconfigure.cache.Cache2kBuilderCustomizer
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.Configuration
import java.util.concurrent.TimeUnit

@Configuration(proxyBeanMethods = false)
class MyCache2kDefaultsConfiguration {

	@Bean
	fun myCache2kDefaultsCustomizer(): Cache2kBuilderCustomizer {
		return Cache2kBuilderCustomizer { builder ->
			builder.entryCapacity(200)
				.expireAfterWrite(5, TimeUnit.MINUTES)
		}
	}
}

Simple

If none of the other providers can be found, a simple implementation using a ConcurrentHashMap as the cache store is configured. This is the default if no caching library is present in your application. By default, caches are created as needed, but you can restrict the list of available caches by setting the cache-names property. For instance, if you want only cache1 and cache2 caches, set the cache-names property as follows:

  • Properties

  • YAML

spring.cache.cache-names=cache1,cache2
spring:
  cache:
    cache-names: "cache1,cache2"

If you do so and your application uses a cache not listed, then it fails at runtime when the cache is needed, but not on startup. This is similar to the way the "real" cache providers behave if you use an undeclared cache.

None

When @EnableCaching is present in your configuration, a suitable cache configuration is expected as well. If you have a custom CacheManager, consider defining it in a separate @Configuration class so that you can override it if necessary. None uses a no-op implementation that is useful in tests, and slice tests use that by default via @AutoConfigureCache.

If you need to use a no-op cache rather than the auto-configured cache manager in a certain environment, set the cache type to none, as shown in the following example:

  • Properties

  • YAML

spring.cache.type=none
spring:
  cache:
    type: "none"