转自：http://blog.sina.com.cn/s/blog_72ef7bea0101basm.html
MyBatis支持第三方二级缓存实现，目前支持Ehcache、Hazelcast和OSCache。
GemFire不在支持的范围，但是可以通过实现org.apache.ibatis.cache.Cache接口来使用。
1、设置MyBatis的Cache全局使用开关：默认是true，如果它配成false，其余各个Mapper XML文件配成支持cache也没用。
<settings> <setting name="cacheEnabled" value="true"/> </settings>
2、各个Mapper XML文件，默认是不采用cache。在配置文件加一行就可以支持cache：
<mapper namespace="org.acme.FooMapper"> <cache type="com.yqu.mybatis.caches.gemfire.GemfireCache"/> ... </mapper>
3、实现GemfireCache
package com.yqu.mybatis.caches.gemfire;
import com.gemstone.gemfire.cache.AttributesFactory;
import com.gemstone.gemfire.cache.CacheFactory;
import com.gemstone.gemfire.cache.Region;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.ibatis.cache.Cache;
import org.apache.ibatis.cache.CacheException;
public final class GemfireCache implements Cache {
private static Region<Object, Object> mybatis_region = null;
private Region<Object, Object> region = null;
private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
private String id;
public void setId(String id) {
this.id = id;
}
public void setRegion(Region<Object, Object> region) {
this.region = region;
}
public Region<Object, Object> getRegion() {
return region;
}
private static synchronized Region<Object, Object> getParentRegion()
{
if(mybatis_region==null)
{
com.gemstone.gemfire.cache.Cache cache = new CacheFactory()
.set("name", "mybatis_gemfire_cache")
.set("cache-xml-file", "gemfire.xml").create();
mybatis_region = cache.getRegion("mybatis_gemfire_region");
}
return mybatis_region;
}
@SuppressWarnings({ "deprecation", "unchecked", "rawtypes" })
public GemfireCache(String id) {
if (id == null) {
throw new IllegalArgumentException("Cache instances require an ID");
}
this.id = id;
region = getParentRegion().getSubregion(id);
if (null == region) {
AttributesFactory attrFactory =
new AttributesFactory(mybatis_region.getAttributes());
region = mybatis_region.createSubregion(id, attrFactory.create());
}
}
public void clear() {
if (null != region) {
try {
region.clear();
} catch (Throwable t) {
throw new CacheException(t);
}
}
}
public String getId() {
return this.id;
}
public Object getObject(Object key) {
Object retVal = null;
if (null != region) {
if (region.containsKey(key.hashCode())) {
try {
retVal = region.get(key.hashCode());
} catch (Throwable t) {
throw new CacheException(t);
}
}
}
return retVal;
}
public ReadWriteLock getReadWriteLock() {
return this.readWriteLock;
}
public int getSize() {
if (null != region) {
try {
return region.size();
} catch (Throwable t) {
throw new CacheException(t);
}
}
return 0;
}
public void putObject(Object key, Object value) {
if (null != region) {
try {
region.put(key.hashCode(), value);
} catch (Throwable t) {
throw new CacheException(t);
}
}
}
public Object removeObject(Object key) {
if (null != region) {
try {
return region.remove(key.hashCode());
} catch (Throwable t) {
throw new CacheException(t);
}
}
return null;
}
@Override
public boolean equals(Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (!(obj instanceof Cache)) {
return false;
}
Cache otherCache = (Cache)obj;
return this.id.equals(otherCache.getId());
}
@Override
public int hashCode() {
return this.id.hashCode();
}
@Override
public String toString() {
return "GemfireCache{" + this.id + "}";
}
}
4、Mapper XML文件配置支持cache后，文件中所有的Mapper statement就支持了。此时要个别对待某条可以通过useCache禁止使用cache：
<select id="inetAton" parameterType="string" resultType="integer" useCache=“false”>
select inet_aton(#{name})
</select>
参考
http://howtodoinjava.com/2013/01/06/how-to-enable-caching-in-ibatis-using-oscache/
http://www.webdbtips.com/60455/
http://blog.csdn.net/xuezhimeng/article/details/7378096
http://grepcode.com/file/repo1.maven.org/maven2/org.mybatis.caches/mybatis-ehcache/1.0.0-RC1/org/mybatis/caches/ehcache/EhcacheCache.java