项目完结，整理一些技术方面的相关收获。
已经记不得EhCacheController这个实现类最早来自于那里了，总之稍加修改后非常有效果，大家就这么用了，感谢最初开源的那位兄弟。这里，主要是做个记录，为以后类似扩展（譬如Memcached）做个准备。
iBatis提供CacheController接口，用于实现第三方缓存架构的扩展。
这里以iBatis 2.3.0，EhCache 1.2.3版本为基础，构建iBatis+EhCache实现。
EhCacheController类：
package com.ibatis.sqlmap.engine.cache.ehcache;
import java.net.URL;
import java.util.Properties;
import net.sf.ehcache.Cache;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Element;
import com.ibatis.sqlmap.engine.cache.CacheController;
import com.ibatis.sqlmap.engine.cache.CacheModel;
/**
* EhCache Implementation of the
* {@link com.ibatis.sqlmap.engine.cache.CacheController} interface to be able
* to use EhCache as a cache implementation in iBatis. You can configure your
* cache model as follows, by example, in your sqlMapping files:
*
* <pre>
* <code>
* <cacheModel id="myCache" readOnly="true" serialize="false"
* type="com.ibatis.sqlmap.engine.cache.EhCacheController" >
* <property name="configLocation"
* value="/path-to-ehcache.xml"/>
* </cacheModel> </code>
* </pre>
*
* Alternatively, you can use a type alias in your type attribute and defining
* the class with a <code><typeAlias></code> declaration:
*
* <pre>
* <code>
* <sqlMapConfig>
* <typeAlias alias="EHCACHE"
* type="com.ibatis.sqlmap.engine.cache.ehcache.EhCacheController" />
* </sqlMapConfig>
* </code>
* </pre>
*
*/
public class EhCacheController implements CacheController {
/**
* The EhCache CacheManager.
*/
private CacheManager cacheManager;
public static final String CONFIG_LOCATION = "configLocation";
/**
* Default Configure Location
*/
public static final String DEFAULT_CONFIG_LOCATION = "/ehcache.xml";
/**
* Flush a cache model.
*
* @param cacheModel
* - the model to flush.
*/
public void flush(CacheModel cacheModel) {
getCache(cacheModel).removeAll();
}
/**
* Get an object from a cache model.
*
* @param cacheModel
* - the model.
* @param key
* - the key to the object.
* @return the object if in the cache, or null(?).
*/
public Object getObject(CacheModel cacheModel, Object key) {
Object result = null;
Element element = getCache(cacheModel).get(key);
if (element != null) {
result = element.getObjectValue();
}
return result;
}
/**
* Put an object into a cache model.
*
* @param cacheModel
* - the model to add the object to.
* @param key
* - the key to the object.
* @param object
* - the object to add.
*/
public void putObject(CacheModel cacheModel, Object key, Object object) {
getCache(cacheModel).put(new Element(key, object));
}
/**
* Remove an object from a cache model.
*
* @param cacheModel
* - the model to remove the object from.
* @param key
* - the key to the object.
* @return the removed object(?).
*/
public Object removeObject(CacheModel cacheModel, Object key) {
Object result = this.getObject(cacheModel, key);
getCache(cacheModel).remove(key);
return result;
}
/**
* Gets an EH Cache based on an iBatis cache Model.
*
* @param cacheModel
* - the cache model.
* @return the EH Cache.
*/
private Cache getCache(CacheModel cacheModel) {
String cacheName = cacheModel.getId();
Cache cache = cacheManager.getCache(cacheName);
return cache;
}
/**
* Shut down the EH Cache CacheManager.
*/
public void finalize() {
if (cacheManager != null) {
cacheManager.shutdown();
}
}
/**
* Configure a cache controller. Initialize the EH Cache Manager as a
* singleton.
*
* @param props
* - the properties object continaing configuration information.
*/
@Override
public void configure(Properties props) {
String configLocation = props.getProperty(CONFIG_LOCATION);
// if can not found ehcache.xml from configLocaion,
// use default configure file.
if (configLocation == null) {
configLocation = DEFAULT_CONFIG_LOCATION;
}
URL url = getClass().getResource(configLocation);
cacheManager = CacheManager.create(url);
}
}
这里默认在根目录下获取ehcache.xml文件，可以通过cacheModel配置进行修改。
在SqlMapConfig.xml文件中配置一个别名，作为全局变量，供其余SqlMap使用
<typeAlias alias="EHCACHE" type="com.ibatis.sqlmap.engine.cache.ehcache.EhCacheController" />
顺便提一句，要使用缓存注意SqlMapConfig.xml文件中settings节点配置cacheModelsEnabled为true！
<settings cacheModelsEnabled="true" useStatementNamespaces="true" ... />
如果要变更ehcache.xml文件路径为/config/ehcache.xml，可以在上述节点中下入如下代码：
<property name="configLocation" value="/config/ehcache.xml" />
然后，就可以通过ehcache.xml控制ehcache缓存了！
举例说明iBatis SqlMap & ehcahce.xml，以免有些兄弟混淆！
以Account类为示例，在SqlMap中的配置为：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMap
PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN"
"http://ibatis.apache.org/dtd/sql-map-2.dtd">
<sqlMap
namespace="Account">
<cacheModel
id="cache"
type="EHCACHE">
<flushInterval
hours="1" />
<!-- flush操作,需要指明 Namespace -->
<flushOnExecute
statement="Account.create" />
</cacheModel>
<typeAlias
alias="account"
type="org.zlex.acl.Account" />
<resultMap
id="accountMap"
class="account">
<result
property="accountId"
column="accountId" />
<result
property="accountName"
column="accountName" />
<result
property="mail"
column="mail" />
<result
property="realName"
column="realName" />
<result
property="status"
column="status" />
<result
property="lastLoginTime"
column="lastLoginTime" />
</resultMap>
<select
id="readByAccountName"
parameterClass="string"
resultMap="accountMap"
cacheModel="cache">
<![CDATA[
SELECT
accountId,
accountName,
mail,
realName,
status,
lastLoginTime
FROM
acl_account
WHERE
accountName = #accountName#
]]>
</select>
<insert
id="create"
parameterClass="account">
<![CDATA[
INSERT INTO
acl_account(
accountName,
mail,
realName,
status,
lastLoginTime
)
VALUES (
#accountName#,
#mail#,
#realName#,
#status#,
#lastLoginTime#
)
]]>
<selectKey
resultClass="long"
keyProperty="accountId">
<![CDATA[select LAST_INSERT_ID() as id ]]>
</selectKey>
</insert>
</sqlMap>
注意：
引用
<select id="readByAccountName" parameterClass="string" resultMap="accountMap" cacheModel="cache">
这里的cacheModel="cache"，对应的在ehcache.xml中就应该是：
<cache name="Account.cache" maxElementsInMemory="10000" eternal="false" maxElementsOnDisk="1000" overflowToDisk="true" timeToIdleSeconds="300" />
因为，我使用了useStatementNamespaces="true"