使用二级缓存提供的供应商：org.hibernate.cache.EhCacheProvider【内存中的缓存满了,就把缓存的数据做存到硬盘上】
  要导入的二个jar包一个配置文件
    truts-2.1.8\lib\commons-logging-1.0.4.jar      org.apache.commons.logging.LogFactory
    spring-framework-2.5.6\lib\concurrent        edu.emory.mathcs.backport.java.util.concurrent.BlockingQueue
    hibernate-distribution-3.6.0.Final\project\etc    ehcache.xml

<ehcache>

    <!-- Sets the path to the directory where cache .data files are created.

         If the path is a Java System Property it is replaced by
         its value in the running VM.

         The following properties are translated:
         user.home - User's home directory
         user.dir - User's current working directory
         java.io.tmpdir - Default temp file path -->
    <diskStore path="c:\cache\"/>


    <!--Default Cache configuration. These will applied to caches programmatically created through
        the CacheManager.

        The following attributes are required for defaultCache:

        maxInMemory       - Sets the maximum number of objects that will be created in memory
        eternal           - Sets whether elements are eternal. If eternal,  timeouts are ignored and the element
                            is never expired.
        timeToIdleSeconds - Sets the time to idle for an element before it expires. Is only used
                            if the element is not eternal. Idle time is now - last accessed time
        timeToLiveSeconds - Sets the time to live for an element before it expires. Is only used
                            if the element is not eternal. TTL is now - creation time
        overflowToDisk    - Sets whether elements can overflow to disk when the in-memory cache
                            has reached the maxInMemory limit.

        -->
    <defaultCache
        maxElementsInMemory="1"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="true"
        />
</ehcache>

<property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property>