hibernate二级缓存

hibernate内建的开源产品提供的高速缓存

• EHCache (org.hibernate.cache.EhCacheProvider)
• OSCache (org.hibernate.cache.OSCacheProvider)
• SwarmCache (org.hibernate.cache.SwarmCacheProvider)
• JBoss TreeCache (org.hibernate.cache.TreeCacheProvider)

Each cache provides different capacities in terms of performance, memory use, and configuration possibilities:

• EHCache is a fast, lightweight, and easy-to-use in-process cache. It supports read-only and read/write caching, and memory- and disk-based caching. However, it does not support clustering.
• OSCache is another open-source caching solution. It is part of a larger package, which also provides caching functionalities for JSP pages or arbitrary objects. It is a powerful and flexible package, which, like EHCache, supports read-only and read/write caching, and memory- and disk-based caching. It also provides basic support for clustering via either JavaGroups or JMS.
• SwarmCache is a simple cluster-based caching solution based on JavaGroups. It supports read-only or nonstrict read/write caching (the next section explains this term). This type of cache is appropriate for applications that typically have many more read operations than write operations.
• JBoss TreeCache is a powerful replicated (synchronous or asynchronous) and transactional cache. Use this solution if you really need a true transaction-capable caching architecture.

ehcache

<hibernate-configuration>
	<session-factory>
		...
		<property name="hibernate.cache.provider_class">
			org.hibernate.cache.EHCacheProvider
		</property>
		...
	</session-factory>
</hibernate-configuration>

 

<class name="cascade.Category" table="CATEGORY">
		<cache usage="read-write"/> 

<ehcache>

    <diskStore path="java.io.tmpdir"/>

    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="true"
        diskPersistent="false"
        diskExpiryThreadIntervalSeconds="120"
        memoryStoreEvictionPolicy="LRU"
        />
        
    <cache name="cascade.Category"
        maxElementsInMemory="300"
        eternal="true"
        overflowToDisk="false"
        />

</ehcache>

 eternal='true'通过超时禁用清除

overflowToDisk="false"禁用基于磁盘的高速缓存溢出

 timeToIdleSeconds="120"定义了以秒为单位的从一个元素最后一次在高速缓存中被访问开始的过期时间

 timeToLiveSeconds="120"定义了以秒为单位的从元素被添加到高速缓存中开始的最大过期时间

 

查询缓存

    <property name="hibernate.cache.use_query_cache">true</property>