异常

org.hibernate.service.spi.ServiceException: Unable to create requested
service [org.hibernate.cache.spi.RegionFactory]
Caused by:
org.hibernate.boot.registry.selector.spi.StrategySelectionException:
Unable to resolve name [org.hibernate.cache.internal.EhCacheRegionFactory] as strategy
[org.hibernate.cache.spi.RegionFactory]

org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.cache.spi.RegionFactory]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:271)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:233)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:210)
    at org.hibernate.boot.internal.MetadataBuilderImpl$MetadataBuildingOptionsImpl.<init>(MetadataBuilderImpl.java:662)
    at org.hibernate.boot.internal.MetadataBuilderImpl.<init>(MetadataBuilderImpl.java:126)
    at org.hibernate.boot.internal.MetadataBuilderImpl.<init>(MetadataBuilderImpl.java:93)
    at org.hibernate.boot.MetadataSources.getMetadataBuilder(MetadataSources.java:125)
    at org.hibernate.boot.MetadataSources.buildMetadata(MetadataSources.java:179)
    at top.sicso.util.HbmUtils.getSessionFactory(HbmUtils.java:21)
    at top.sicso.select.test.TestApp2.<init>(TestApp2.java:21)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at org.junit.runners.BlockJUnit4ClassRunner.createTest(BlockJUnit4ClassRunner.java:217)
    at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:266)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:678)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.hibernate.boot.registry.selector.spi.StrategySelectionException: Unable to resolve name [org.hibernate.cache.internal.EhCacheRegionFactory] as strategy [org.hibernate.cache.spi.RegionFactory]
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.selectStrategyImplementor(StrategySelectorImpl.java:126)
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:194)
    at org.hibernate.boot.registry.selector.internal.StrategySelectorImpl.resolveStrategy(StrategySelectorImpl.java:161)
    at org.hibernate.cache.internal.RegionFactoryInitiator.initiateService(RegionFactoryInitiator.java:67)
    at org.hibernate.cache.internal.RegionFactoryInitiator.initiateService(RegionFactoryInitiator.java:28)
    at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:88)
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:259)
    ... 31 more

hibernate.cfg.xml配置

<!-- 开启二级缓存默认 不开起 -->
<property name="hibernate.cache.use_second_level_cache">true</property>
<property name="hibernate.cache.use_query_cache">true</property>

<!-- 设置二级缓存实现源 -->
<property name="hibernate.cache.region.factory_class">
    org.hibernate.cache.internal.EhCacheRegionFactory
</property>

  此处的二级缓存实现源是根据hibernate.properties文件中的说明配置的。
 hibernate4及以后的版本都是：
   hibernate.cache.region.factory_class 属性来配置缓存实现源

#hibernate.cache.region.factory_class org.hibernate.cache.internal.EhCacheRegionFactory

这样的配置导致了上面的异常。

原因：
 hibernate 5.2提供的ehcache的jar包并没有

  org.hibernate.cache.internal.EhCacheRegionFactory

optional中ehcache下的jar包

在
  hibernate-ehcache-5.2.17.Final.jar
中只有
   org.hibernate.cache.ehcache.EhCacheRegionFactory

因此将配置文件中的 org.hibernate.cache.internal.EhCacheRegionFactory

改为 org.hibernate.cach.EhCacheRegionFactory 即可

<property name="hibernate.cache.region.factory_class">
    org.hibernate.cach.EhCacheRegionFactory
</property>

测试：

@Test
    public void testHbm2(){

        Session session = sessionFactory.openSession();
        Order order = session.get(Order.class, 1);
        System.out.println(order);
        Order order2 = session.get(Order.class, 1);
        System.out.println(order2);
        session.close();

        System.out.println();

        Session session2 = sessionFactory.openSession();
        Order order3 = session2.get(Order.class, 1);
        System.out.println(order3);
        session2.close();

    }

输出 ：

Hibernate: 
    select
        order0_.sid as sid1_3_0_,
        order0_.price as price2_3_0_,
        order0_.cus_id as cus_id3_3_0_,
        customer1_.cid as cid1_1_1_,
        customer1_.cname as cname2_1_1_ 
    from
        t_order order0_ 
    left outer join
        customer customer1_ 
            on order0_.cus_id=customer1_.cid 
    where
        order0_.sid=?
Order [sid=1, price=0, customerId=1]
Order [sid=1, price=0, customerId=1]

Order [sid=1, price=0, customerId=1]

结果：
  只执行一次sql查询，第三次输出是从二级缓存中取得的数据
二级缓存配置成功。