Hibernate Memcached 配置

官方网址: http://code.google.com/p/hibernate-memcached/
目前最新版本为1.0, 支持Hibernate3.3.

下面是具体的使用方法:
hibernate-memcached需要支持的类库如下:

hibernate-memcached-<version>.jarmemcached-2.1.jarspy-2.4.jarcommons-codec 1.3slf4j-1.5.0.jar 如果你的项目使用的是Log4j,可以用 slf4j-log4j12-1.5.0.jar

配置方法如下：

配置Hibernate使用cache提供类

hibernate.cache.provider_classcom.googlecode.hibernate.memcached.MemcachedCacheProvider

?

设置查询缓存开启

hibernate.cache.use_query_cachetrue

其它一些参数设置说明:

PropertyDefaultDescriptionhibernate.memcached.serverslocalhost:11211memcached 服务地址，多个用空格分隔
格式host:porthibernate.memcached.cacheTimeSeconds300缓存失效时间,单位秒hibernate.memcached.keyStrategyHashCodeKeyStrategy缓存Key生成存储HashCode算法hibernate.memcached.readBufferSizeDefaultConnectionFactory.DEFAULT_READ_BUFFER_SIZE从服务器读取数据缓存区大小hibernate.memcached.operationQueueLengthDefaultConnectionFactory.DEFAULT_OP_QUEUE_LENMaximum length of the operation queue returned by this connection factoryhibernate.memcached.operationTimeoutDefaultConnectionFactory.DEFAULT_OPERATION_TIMEOUT操作超时时间设置hibernate.memcached.hashAlgorithmHashAlgorithm.KETAMA_HASH新增缓存数据到服务器时使用的Hash散列算法。 当 hibernate-memcached 设置成 KETAMA_HASH算法时,注意:默认客户端API使用的是 HashAlgorithm.NATIVE_HASHhibernate.memcached.clearSupportedfalse支持MemcachedCache.clear()方法清空缓存。
建议不要开启。

配置示例(本文以Hibernate3.3-entitymanager为例)
配置 persistence.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence"" target="_new">http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0">

<persistence-unit name="entityManager" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<jta-data-source>java:comp/env/jdbc/qualitydb</jta-data-source>

<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.PostgreSQLDialect" />
<property name="hibernate.max_fetch_depth" value="3" />
<property name="hibernate.show_sql" value="true" />


<property name="hibernate.cache.region_prefix" value="quality.cache.ehcache"/>
<property name="hibernate.cache.use_second_level_cache" value="true"/>
<property name="hibernate.cache.use_structured_entries" value="true"/>
<property name="hibernate.cache.use_query_cache" value="true"/>
<property name="hibernate.cache.provider_class" value="com.googlecode.hibernate.memcached.MemcachedCacheProvider"/>
<property name="hibernate.memcached.servers" value="localhost:11211"/>

</properties>

</persistence-unit>

</persistence>

启动后，提示如下：
2008-08-28 17:10:08,312 JCLLoggerAdapter.java265 INFO -- Starting MemcachedClient...
2008-08-28 17:10:08.718 INFO net.spy.memcached.MemcachedConnection: Added {QA sa=localhost/127.0.0.1:11211, #Rops=0, #Wops=0, #iq=0, topRop=null, topWop=null, toWrite=0, interested=0} to connect queue
2008-08-28 17:10:08.750 INFO net.spy.memcached.MemcachedConnection: Connection state changed for sun.nio.ch.SelectionKeyImpl@16e59da

表示我们第一步配置已经成功了，接下来，对需要进行缓存的Entity进行配置

1 @Entity
2 @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)//设置要求缓存
3 public class Student {
4
5 ?? @Id
6 ?? @Column(length=32)
7 ????private String id;
8 ????
9 ???? @Column(length=20)
10 ????private string name;
11 ????
12 ???? @OneToMany
13 ???? @Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
14 ????private Set<Book> books;
15
16 }

Ok,现在配置已经完成。