Example of SpringBoot's method to use EhCache manually

SpringBoot implements data caching function at the annotation level, based on Spring's AOP technology. All cache configurations are only configured at the annotation level, like declarative transactions.

Spring defines CacheManager and Cache interfaces to unify different caching technologies. Among them, CacheManager is an abstract interface for various caching technologies provided by Spring. The Cache interface contains various cache operations.

CacheManger

For different cache technologies, different cacheManagers need to be implemented. Spring defines the following cacheManger implementation.

The regular SpringBoot has automatically configured EhCache, Collection, Guava, ConcurrentMap and other caches for us, and the ConcurrentMapCacheManager is used by default. SpringBoot's application.properties configuration file, configured using the properties of the spring.cache prefix.

Application Configuration

 spring.cache.type=#Cached technical type spring.cache.cache-names=The name of the application starts to create the cache, spring.cache.ehcache.config=ehcache configuration file location spring.cache.infinispan.config=infinispan configuration file location spring.cache.jcache.config=jcache configuration file location spring.cache.jcache.provider=Specify the implementation class of jcache when multiple jcache implementation classes

Entry class configuration

Add annotation @EnableCaching

Cache annotation

Manually use EhCache

During the actual development process, there is a situation where there is no use of annotations and you need to add cache yourself. Let’s take Ehcache as an example and briefly write down the configuration process.

1. Add dependencies

Introduce springboot-cache and ehcache. It should be noted that EhCache does not require version configuration, and the root pom of SpringBoot has been integrated.

 <!-- Cache--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-cache</artifactId> </dependency> <!-- ehcache --> <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> </dependency>

2. Entry class configuration

Add annotation @EnableCaching

 @SpringBootApplication@EnableCachingpublic class DemoApplication {}

3. EhCache configuration

In the src/main/resources directory, add the ehcache.xml file, see the content at the end of the article.

4. Application.application configuration

 # Configure ehcache cache spring.cache.type=ehcache# Specify the path of ehcache configuration file spring.cache.ehcache.config=classpath:/ehcache.xml

5. Use Cache

Inject SpringBoot's automatically configured bean, org.springframework.cache.CacheManager.

A simple test class:

 package com.bbf.frame.test;import com.bbf.frame.Application;import org.apache.commons.lang3.StringUtils;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.boot.test.context.SpringBootTest;import org.springframework.cache.Cache;import org.springframework.cache.CacheManager;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;import org.springframework.test.context.web.WebAppConfiguration;import javax.annotation.Resource;@RunWith(SpringJUnit4ClassRunner.class)@WebAppConfiguration@SpringBootTest(classes = Application.class, webEnvironment = SpringBootTest.WebEnvironment.MOCK)public class TestCache { @Resource private CacheManager cacheManager; @Test public void cacheTest() { // Show all Cache spaces System.out.println(StringUtils.join(cacheManager.getCacheNames(), ",")); Cache cache = cacheManager.getCache("userCache"); cache.put("key", "123"); System.out.println("Cache Success"); String res = cache.get("key", String.class); System.out.println(res); }}

Appendix EhCache.xml

 <?xml version="1.0" encoding="UTF-8"?><ehcache xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation = "http://ehcache.org/ehcache.xsd" updateCheck = "false"> <!-- Specify a file directory. When EHCache writes data to the hard disk, the data will be written to this file directory --> <diskStore path = "java.io.tmpdir"/> <!-- Default Management Policy --> <defaultCache eternal = "false" maxElementsInMemory = "10000" overflowToDisk = "true" diskPersistent = "false" timeToIdleSeconds = "120" timeToLiveSeconds = "120" diskExpiryThreadIntervalSeconds = "120" memoryStoreEvictionPolicy = "LRU"/> <!-- This cache can survive up to timeToLiveSeconds seconds. If the period exceeds timeToIdleSeconds seconds and the cache is invalidated --> <cache name = "userCache" eternal = "false" maxElementsInMemory = "100" overflowToDisk = "false" diskPersistent = "false" timeToIdleSeconds = "120" timeToLiveSeconds = "180" memoryStoreEvictionPolicy = "LRU"/> <!-- maxElementsInMemory The maximum number of cached objects in memory, look at your heap size to do it --> <!-- eternal: true means that the object will never expire. At this time, the timeToIdleSeconds and timeToLiveSeconds properties will be ignored, and the default is false --> <!-- maxElementsOnDisk: The maximum number of cached objects in the hard disk, if 0 means infinity --> <!-- overflowToDisk: true means that when the number of objects cached in the memory reaches the maxElementsInMemory limit, the overflowed objects will be written to the hard disk cache. Note: If the cached object is to be written to the hard disk, the object must implement the Serializable interface. --> <!-- diskSpoolBufferSizeMB: Disk cache size, default is 30MB. Each cache should have its own cache area. --> <!-- diskPersistent: Whether to cache virtual machine restart data --> <!-- diskExpiryThreadIntervalSeconds: The disk failure thread run time interval, default is 120 seconds --> <!-- timeToIdleSeconds: Sets the maximum time to allow the object to be idle, in seconds. When the object has been accessed for the last time, if the timeToIdleSeconds property value exceeds the timeToIdleSeconds property value, the object will expire and EHCache will clear it from the cache. This property is only valid if the eternal property is false. If the value of this property is 0, it means that the object can be idle indefinitely --> <!-- timeToLiveSeconds: Sets the maximum time the object allows to exist in the cache, in seconds. When the object has been stored in the cache, if the time in the cache exceeds the timeToLiveSeconds property value, the object will expire and EHCache will clear it from the cache. This property is only valid if the eternal property is false. If the property value is 0, it means that the object can exist in the cache indefinitely. timeToLiveSeconds must be greater than the timeToIdleSeconds property to make sense --> <!-- memoryStoreEvictionPolicy: When the maxElementsInMemory limit is reached, Ehcache will clean up memory according to the specified policy. Optional policies are: LRU (latest recently used, default policy), FIFO (first in, first out), and LFU (minimum number of visits). --></ehcache>

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