最近项目需用Redis来实现Mybatis缓存方案。
mybatis默认缓存是PerpetualCache，可以查看一下它的源码，发现其是Cache接口的实现；那么我们的缓存只要实现该接口即可。
该接口有以下方法需要实现：
String getId(); int getSize(); void putObject(Object key, Object value); Object getObject(Object key); Object removeObject(Object key); void clear(); ReadWriteLock getReadWriteLock();实现类：
import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock;import org.apache.ibatis.cache.Cache;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import redis.clients.jedis.Jedis;import redis.clients.jedis.JedisPool;import redis.clients.jedis.JedisPoolConfig;public class MybatisRedisCache implements Cache {private static Logger logger = LoggerFactory.getLogger(MybatisRedisCache.class);private Jedis redisClient=createReids(); /** The ReadWriteLock. */private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();private String id;public MybatisRedisCache(final String id) {if (id == null) {throw new IllegalArgumentException("Cache instances require an ID");}logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>MybatisRedisCache:id="+id);this.id = id;} @Overridepublic String getId() {return this.id;}@Overridepublic int getSize() {return Integer.valueOf(redisClient.dbSize().toString());}@Overridepublic void putObject(Object key, Object value) {logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>putObject:"+key+"="+value);redisClient.set(SerializeUtil.serialize(key.toString()), SerializeUtil.serialize(value));}@Overridepublic Object getObject(Object key) {Object value = SerializeUtil.unserialize(redisClient.get(SerializeUtil.serialize(key.toString())));logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>getObject:"+key+"="+value);return value;}@Overridepublic Object removeObject(Object key) {return redisClient.expire(SerializeUtil.serialize(key.toString()),0);}@Overridepublic void clear() {redisClient.flushDB();}@Overridepublic ReadWriteLock getReadWriteLock() {return readWriteLock;}protected static Jedis createReids(){JedisPool pool = new JedisPool(new JedisPoolConfig(), "10.12.162.85");return pool.getResource();}public class SerializeUtil {public static byte[] serialize(Object object) {ObjectOutputStream oos = null;ByteArrayOutputStream baos = null;try {//序列化baos = new ByteArrayOutputStream();oos = new ObjectOutputStream(baos);oos.writeObject(object);byte[] bytes = baos.toByteArray();return bytes;} catch (Exception e) { e.printStackTrace();}return null;}public static Object unserialize(byte[] bytes) {ByteArrayInputStream bais = null;try {//反序列化bais = new ByteArrayInputStream(bytes);ObjectInputStream ois = new ObjectInputStream(bais);return ois.readObject();} catch (Exception e) {}return null;}配置Mybatis SessionFactory：
<!– SessionFactory –><bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"><property name="dataSource" ref="dataSource" /><property name="configurationProperties"><props><prop key="cacheEnabled">true</prop><!– 查询时，，关闭关联对象即时加载以提高性能 –><prop key="lazyLoadingEnabled">true</prop><!– 设置关联对象加载的形态，此处为按需加载字段(加载字段由SQL指定)，不会加载关联表的所有字段，以提高性能 –><prop key="aggressiveLazyLoading">false</prop><!– 对于未知的SQL查询，允许返回不同的结果集以达到通用的效果 –><prop key="multipleResultSetsEnabled">true</prop><!– 允许使用列标签代替列名 –><prop key="useColumnLabel">true</prop><!– 允许使用自定义的主键值(比如由程序生成的UUID 32位编码作为键值)，数据表的PK生成策略将被覆盖 –><prop key="useGeneratedKeys">true</prop><!– 给予被嵌套的resultMap以字段-属性的映射支持 –><prop key="autoMappingBehavior">FULL</prop><!– 对于批量更新操作缓存SQL以提高性能 –><prop key="defaultExecutorType">BATCH</prop><!– 数据库超过25000秒仍未响应则超时 –><prop key="defaultStatementTimeout">25000</prop></props></property></bean>
最后在需要缓存的DAO类上添加@CacheNamespace(implementation=MybatisRedisCache.class )
这样就完成了Mybatis自定义缓存的实现。
参考文件：1、
2、MyBatis 3 User Guide
发光并非太阳的专利，我也可以发光 。
