我正在尝试使用ehcache实现来获得二级hibernate缓存.
我确定这是我正在做的一些明显的noob错误,但我看不出它是什么!
为了测试我的缓存,我正在做以下事情:
创建一个对象并保存它.我在事务中得到了一次,在那里我可以看到我在没有数据库命中的情况下返回对象,这只是休眠的第一级缓存.
然后我提交事务并开始一个新会话.
这次,当我'得到'对象时,我可以在调试中看到来自ehcache的缓存未命中.因为我将它保存在上一个事务中,所以我原本期望该对象在缓存中?
这是我的代码:
Session session = getSession(); session.beginTransaction(); Test1 test1a = new Test1(); test1a.setId(5); test1a.setName("Test 1"); test1a.setValue(10); // Touch it session.save(test1a); // Now get it Test1 test1b = (Test1)session.get(Test1.class, 5); // Within a transaction, the session caches it - no db hit System.out.println("GOT object with value "+test1b.getValue()); session.getTransaction().commit(); System.out.println("Between sessions"); session = getSession(); session.beginTransaction(); test1b = (Test1)session.get(Test1.class, 5); System.out.println("GOT object with value "+test1b.getValue()); session.getTransaction().commit();
这是我的hibernate.cfg.xml的相关部分
org.hibernate.cache.EhCacheProvider
还有我的ehcache.xml
还有我的注释
@Entity @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE) public class Test1 {
和调试日志
11:21:03,474 DEBUG CacheManager:239 - Configuring ehcache from classpath. 11:21:03,479 DEBUG ConfigurationFactory:122 - Configuring ehcache from ehcache.xml found in the classpath: file:/Users/bw/Documents/workspace/hibernate1/target/classes/ehcache.xml 11:21:03,479 DEBUG ConfigurationFactory:87 - Configuring ehcache from URL: file:/Users/brucewood/Documents/workspace/hibernate1/target/classes/ehcache.xml 11:21:03,480 DEBUG ConfigurationFactory:139 - Configuring ehcache from InputStream 11:21:03,485 DEBUG BeanHandler:213 - Ignoring ehcache attribute xmlns:xsi 11:21:03,485 DEBUG BeanHandler:213 - Ignoring ehcache attribute xsi:noNamespaceSchemaLocation 11:21:03,517 DEBUG ConfigurationHelper:208 - No CacheManagerEventListenerFactory class specified. Skipping... 11:21:03,518 DEBUG ConfigurationHelper:183 - No CachePeerListenerFactoryConfiguration specified. Not configuring a CacheManagerPeerListener. 11:21:03,518 DEBUG ConfigurationHelper:159 - No CachePeerProviderFactoryConfiguration specified. Not configuring a CacheManagerPeerProvider. 11:21:03,525 DEBUG ConfigurationHelper:135 - No BootstrapCacheLoaderFactory class specified. Skipping... 11:21:03,526 DEBUG ConfigurationHelper:135 - No BootstrapCacheLoaderFactory class specified. Skipping... 11:21:03,532 DEBUG MemoryStore:73 - Initialized net.sf.ehcache.store.LruMemoryStore for com.play.hibernate1.Test1 11:21:03,533 DEBUG LruMemoryStore:71 - com.play.hibernate1.Test1 Cache: Using SpoolingLinkedHashMap implementation 11:21:03,533 DEBUG Cache:429 - Initialised cache: com.play.hibernate1.Test1 1528 [Finalizer] INFO org.hibernate.connection.DriverManagerConnectionProvider - cleaning up connection pool: jdbc:mysql://localhost:3306/play 1668 [main] INFO org.hibernate.impl.SessionFactoryObjectFactory - Not binding factory to JNDI, no JNDI name configured GOT object with value 10 Hibernate: /* insert com.play.hibernate1.Test1 */ insert into Test1 (name, value, id) values (?, ?, ?) 1274984463818|1|1|batch|/* insert com.play.hibernate1.Test1 */ insert into Test1 (name, value, id) values (?, ?, ?)|/* insert com.play.hibernate1.Test1 */ insert into Test1 (name, value, id) values ('Test 1', 10, 5) 1274984463820|1|1|statement|/* insert com.play.hibernate1.Test1 */ insert into Test1 (name, value, id) values (?, ?, ?)|/* insert com.play.hibernate1.Test1 */ insert into Test1 (name, value, id) values ('Test 1', 10, 5) 1274984463821|1|1|commit|| Between sessions 11:21:03,823 DEBUG EhCache:68 - key: com.play.hibernate1.Test1#5 11:21:03,823 DEBUG MemoryStore:138 - com.play.hibernate1.Test1Cache: com.play.hibernate1.Test1MemoryStore miss for com.play.hibernate1.Test1#5 11:21:03,823 DEBUG Cache:661 - com.play.hibernate1.Test1 cache - Miss 11:21:03,824 DEBUG EhCache:77 - Element for com.play.hibernate1.Test1#5 is null Hibernate: /* load com.play.hibernate1.Test1 */ select test1x0_.id as id0_0_, test1x0_.name as name0_0_, test1x0_.value as value0_0_ from Test1 test1x0_ where test1x0_.id=? 1274984463829|4|1|statement|/* load com.play.hibernate1.Test1 */ select test1x0_.id as id0_0_, test1x0_.name as name0_0_, test1x0_.value as value0_0_ from Test1 test1x0_ where test1x0_.id=?|/* load com.play.hibernate1.Test1 */ select test1x0_.id as id0_0_, test1x0_.name as name0_0_, test1x0_.value as value0_0_ from Test1 test1x0_ where test1x0_.id=5 1274984463831|-1||resultset|/* load com.play.hibernate1.Test1 */ select test1x0_.id as id0_0_, test1x0_.name as name0_0_, test1x0_.value as value0_0_ from Test1 test1x0_ where test1x0_.id=5|name0_0_ = Test 1, value0_0_ = 10 GOT object with value 10 1274984463834|0|1|commit||
谢谢你的帮助!
问题是我使用的是NONSTRICT_READ_WRITE.它似乎符合文档中这个解释的法案:
如果应用程序仅偶尔需要更新数据(即,如果两个事务不太可能同时尝试更新同一项),并且不需要严格的事务隔离,则非严格读写缓存可能是合适的.如果在JTA环境中使用缓存,则必须指定hibernate.transaction.manager_lookup_class.在其他环境中,应确保在调用Session.close()或Session.disconnect()时完成事务.
但实际上它看起来并没有将保存的对象添加到缓存中.文档在这里有点薄,IMO.使用Hibernate对Java Persistence中的缓存选项有一个更好的处理方法,尽管对于数据实际发生的具体解释仍然有点薄弱.无论如何..
我将缓存选项更改为READ_WRITE,现在它按预期工作.
另请注意,第一次将对象添加到缓存时,您会在ehcache调试中获得"缓存未命中".据推测,它在其缓存中查找,发现对象不存在,记录未命中,然后添加对象.在那之后,你会得到'命中'.