如何在Spring Boot3/Hibernate6/JCache/Ehcache3中获取缓存实例？

技术栈 #

• Spring Boot 3
• Hibernate 6
• JCache (Ehcache 3)

背景 #

原本认为获取缓存实例是企业应用的常规操作，实现起来应该很容易，但实际找不到适配现代Spring Boot应用的有效资料。当前缓存功能正常，已能通过JMX访问统计信息，但需要获取单个缓存实例来手动清除缓存、查看当前条目数量。

pom.xml依赖片段 #

<dependency>
    <groupId>org.hibernate.orm</groupId>
    <artifactId>hibernate-jcache</artifactId>
</dependency>
<dependency>
    <groupId>org.ehcache</groupId>
    <artifactId>ehcache</artifactId>
    <classifier>jakarta</classifier>
</dependency>

ehcache.xml配置 #

<?xml version="1.0" encoding="UTF-8"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns="http://www.ehcache.org/v3"
        xmlns:jsr107="http://www.ehcache.org/v3/jsr107"
        xsi:schemaLocation="http://www.ehcache.org/v3
                            http://www.ehcache.org/schema/ehcache-core.xsd">

    <cache-template name="status-cache">
        <expiry><ttl>3600</ttl></expiry>
        <resources>
            <heap>10</heap>
            <offheap unit="MB">1</offheap>
        </resources>
    </cache-template>
    
    <cache alias="email-status-cache" uses-template="status-cache"/>
</config>

application.yml配置 #

spring.jpa.properties:
  -hibernate.cache.region.factory_class: "org.hibernate.cache.jcache.internal.JCacheRegionFactory"
  -hibernate.cache.use_second_level_cache: true
  -hibernate.javax.cache.provider: "org.ehcache.jsr107.EhcacheCachingProvider"
  -hibernate.javax.missing_cache_strategy: fail
  -hibernate.javax.cache.uri: "classpath:ehcache.xml"
  -hibernate.generate_statistics: true
  -jakarta.persistence.sharedCache.mode: ENABLE_SELECTIVE

可缓存实体类EmailStatus #

@Entity
@Immutable
@Access(AccessType.FIELD)
@org.hibernate.annotations.Cache(region = "email-status-cache",
                                 usage = CacheConcurrencyStrategy.READ_ONLY)
@Table(name = "email_status")
public class EmailStatus implements Serializable {

    //...
}

当前可用的JMX统计代码 #

MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();

try {
    Set<ObjectInstance> cacheBeans = mBeanServer.queryMBeans(ObjectName.getInstance("javax.cache:type=CacheStatistics,CacheManager=*,Cache=*"), null);

    for (ObjectInstance cacheBean : cacheBeans) {
        CacheStatisticsMXBean cacheStatisticsMXBean = JMX.newMBeanProxy(mBeanServer, cacheBean.getObjectName(), CacheStatisticsMXBean.class);
        logger.info(cacheStatisticsMXBean.getCacheHits());
    }
} catch (MalformedObjectNameException e) { }

失败的尝试 #

1. 注入Spring CacheManager

   Cache cache = cacheManager.getCache("email-status-cache");
   

   返回null，此方法无效。

2. 注入JCacheCacheManager

   Cache cache = jCacheCacheManager.getCache("email-status-cache");
   

   同样返回null。

3. 直接通过Ehcache StatisticsService访问

   StatisticsService service = new DefaultStatisticsService();
   org.ehcache.CacheManager cm = CacheManagerBuilder.newCacheManagerBuilder().using(service).build();
   cm.init();
   
   CacheStatistics stats = service.getCacheStatistics("email-status-cache");
   long heapCount = stats.getTierStatistics().get("Onheap").getMappings();
   

   抛出IllegalArgumentException: Unknown cache: email-status-cache异常，使用全限定名称替代缓存别名也无济于事。

问题 #

如何在Spring Boot 3中，通过JCache facade获取适配Hibernate 6的Ehcache 3缓存实例？

内容的提问来源于stack exchange，提问作者Slevin