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配置Hibernate二级缓存
首先找到配置EHCahe二级缓存需要添加的jar包
hibernate-release-4.1.9.Final→lib→optional→ehcache→下的ehcache-core-2.4.3.jar和hibernate-ehcache-4.1.9.Final.jar还有slf4j-api-1.6.1.jar!
然后再从hibernate-release-4.1.9.Final→project→etc→把ehcache.xml复制到src目录下.把缓存.xml没用的都删了,留下最终:
<ehcache>
<!-- 缓存路径 -->
<diskStore path="E:\SecondCache"/> //自己配置
<defaultCache
maxElementsInMemory="10000"
eternal="false"
timeToIdleSeconds="120"
timeToLiveSeconds="120"
overflowToDisk="true"
/>
</ehcache>
再在hibernate.cfg.xml里开启和配置缓存:
<!-- 开启二级缓存 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<!-- 高速缓存提供程序 -->
<property name="hibernate.cache.region.factory_class">
org.hibernate.cache.ehcache.EhCacheRegionFactory
</property>
最后在实体类的xml文件里设置缓存: <cache usage="read-write"/>
如:
<hibernate-mapping>
<class name="cn.jnit.bean.User" table="T_user">
<cache usage="read-write"/>
<id name="id">
<generator class="sequence">
</generator>
</id>
<property name="pwd"></property>
<property name="name"></property>
<one-to-one name="ud" class="cn.jnit.bean.UserDetail" cascade="all" ></one-to-one>
</class>
</hibernate-mapping>
如果查询的是集合的话:也需要在<SET>里设置:
<hibernate-mapping>
<class name="cn.jbit.bean.Dept" table="DEPT">
<cache usage="read-write" />
<id name="deptno">
<generator class="sequence"></generator>
</id>
<property name="dname"></property>
<property name="loc"></property>
<set name="emps" cascade="save-update" inverse="true" order-by="empno desc"
lazy="false">
<cache usage="read-only" />
<key column="deptno"></key>
<one-to-many class="cn.jbit.bean.Emp" />
</set>
</class>
</hibernate-mapping>.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
如果配置文件里没有<SET>,不必设置,QUERY的查询语句优化的话,需要开启查询缓存→<!-- 开启查询缓存 -->
<property name="hibernate.cache.query_cache_factory">true</property>
下面是我一对一关系里测试的数据,切记:
不 是 Iterator<User> iterator=ses.createQuery(hql).setCacheable(true). list().iterator();
Iterator<User> iterator=ses.createQuery(hql).setCacheable(true).iterate();
Session ses=HibernateSessionFactory.getSession();
String hql="from User";
List<User> list = ses.createQuery(hql).setCacheable(true).list();
System.out.println(list.size());
HibernateSessionFactory.closeSession();
ses=HibernateSessionFactory.getSession();
Iterator<User> iterator = ses.createQuery(hql).setCacheable(true).iterate();
while (iterator.hasNext()) {
User user = (User) iterator.next();
System.out.println(user.getId());
}
ses.close();
配置Hibernate二级缓存