redis的安装http://liuyieyer.iteye.com/blog/2078093
redis的主从高可用 http://liuyieyer.iteye.com/blog/2078095
Mybatis 的使用不多说。
Mybatis为了方便我们扩展缓存定义了一个Cache接口，看看ehcache-mybatis的源码就明白了。我们要使用自己的cache同样的实现Cache接口即可。直接上代码
public class RedisCache implements Cache {
private static Log logger = LogFactory.getLog(RedisCache.class);
private Jedis redisClient = createClient();
/** The ReadWriteLock. */
private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
private String id;
public RedisCache(final String id) {
if (id == null) {
throw new IllegalArgumentException("Cache instances require an ID");
}
logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>MybatisRedisCache:id=" + id);
this.id = id;
}
@Override
public String getId() {
return this.id;
}
@Override
public int getSize() {
return Integer.valueOf(redisClient.dbSize().toString());
}
@Override
public void putObject(Object key, Object value) {
logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>putObject:" + key + "=" + value);
redisClient.set(SerializeUtil.serialize(key.toString()), SerializeUtil.serialize(value));
}
@Override
public Object getObject(Object key) {
Object value = SerializeUtil.unserialize(redisClient.get(SerializeUtil.serialize(key.toString())));
logger.debug(">>>>>>>>>>>>>>>>>>>>>>>>getObject:" + key + "=" + value);
return value;
}
@Override
public Object removeObject(Object key) {
return redisClient.expire(SerializeUtil.serialize(key.toString()), 0);
}
@Override
public void clear() {
redisClient.flushDB();
}
@Override
public ReadWriteLock getReadWriteLock() {
return readWriteLock;
}
protected static Jedis createClient() {
try {
JedisPool pool = new JedisPool(new JedisPoolConfig(), "172.60.0.172");
return pool.getResource();
} catch (Exception e) {
e.printStackTrace();
}
throw new RuntimeException("初始化连接池错误");
}
}
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) {
if(bytes == null)return null;
ByteArrayInputStream bais = null;
try {
// 反序列化
bais = new ByteArrayInputStream(bytes);
ObjectInputStream ois = new ObjectInputStream(bais);
return ois.readObject();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}在看ehcache-mybatis的源码 它真正使用cache的方式是通过集成org.apache.ibatis.cache.decorators.LoggingCache 这个类实现的，照猫画虎，直接我们也继承
public class LoggingRedisCache extends LoggingCache {
public LoggingRedisCache(String id) {
super(new RedisCache(id));
}
}在mapper.xml中添加如下cache标签
<!-- 启用缓存 -->
<cache type="cn.seafood.cache.LoggingRedisCache" />在mybatis的核心文件中开启缓存
<settings>
<!-- 这个配置使全局的映射器启用或禁用缓存 -->
<setting name="cacheEnabled" value="true" />
<!-- 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 -->
<setting name="multipleResultSetsEnabled" value="true"/>
<!-- 配置默认的执行器。SIMPLE 执行器没有什么特别之处。REUSE 执行器重用预处理语句。BATCH 执行器重用语句和批量更新 -->
<setting name="defaultExecutorType" value="REUSE" />
<!-- 全局启用或禁用延迟加载。当禁用时，所有关联对象都会即时加载。 -->
<setting name="lazyLoadingEnabled" value="false" />
<setting name="aggressiveLazyLoading" value="true" />
<!-- <setting name="enhancementEnabled" value="true"/> -->
<!-- 设置超时时间，它决定驱动等待一个数据库响应的时间。 -->
<setting name="defaultStatementTimeout" value="25000" />
</settings><setting name="lazyLoadingEnabled" value="false" />
<setting name="aggressiveLazyLoading" value="true" />
注意着两个属性，需要把属性延迟加载和关联对象加载给关闭了，不然放进redis中的cglib代理对象，在对数据发生更改的时候，会出错。
在上一篇文中的Cahe类存在各种问题如：一直使用同一个连接，每次都创建新的Cache，项目中老是爆出connection timeout 的异常，存储的key过长等等一系列的问题，解决问题最好的办法就是看源码和看官方的文档说明，jedis的文档还是够用的，接下来把cache也改造以下附上代码。
package cn.seafood.cache;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.ibatis.cache.Cache;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.exceptions.JedisConnectionException;
import cn.seafood.util.PropertiesLoader;
/**
*
* @ClassName: RedisCache
* @Description: TODO(使用第三方缓存服务器redis，处理二级缓存)
* @author LiuYi
* @date 2014年6月9日 下午1:37:46
*
*/
public class RedisCache implements Cache {
private static Log log = LogFactory.getLog(RedisCache.class);
/** The ReadWriteLock. */
private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
private String id;
public RedisCache(final String id) {
if (id == null) {
throw new IllegalArgumentException("必须传入ID");
}
log.debug("MybatisRedisCache:id=" + id);
this.id=id;
}
@Override
public String getId() {
return this.id;
}
@Override
public int getSize() {
Jedis jedis = null;
JedisPool jedisPool = null;
int result = 0;
boolean borrowOrOprSuccess = true;
try {
jedis = CachePool.getInstance().getJedis();
jedisPool = CachePool.getInstance().getJedisPool();
result = Integer.valueOf(jedis.dbSize().toString());
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
jedisPool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
jedisPool.returnResource(jedis);
}
return result;
}
@Override
public void putObject(Object key, Object value) {
if(log.isDebugEnabled())
log.debug("putObject:" + key.hashCode() + "=" + value);
if(log.isInfoEnabled())
log.info("put to redis sql :" +key.toString());
Jedis jedis = null;
JedisPool jedisPool = null;
boolean borrowOrOprSuccess = true;
try {
jedis = CachePool.getInstance().getJedis();
jedisPool = CachePool.getInstance().getJedisPool();
jedis.set(SerializeUtil.serialize(key.hashCode()), SerializeUtil.serialize(value));
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
jedisPool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
jedisPool.returnResource(jedis);
}
}
@Override
public Object getObject(Object key) {
Jedis jedis = null;
JedisPool jedisPool = null;
Object value = null;
boolean borrowOrOprSuccess = true;
try {
jedis = CachePool.getInstance().getJedis();
jedisPool = CachePool.getInstance().getJedisPool();
value = SerializeUtil.unserialize(jedis.get(SerializeUtil.serialize(key.hashCode())));
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
jedisPool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
jedisPool.returnResource(jedis);
}
if(log.isDebugEnabled())
log.debug("getObject:" + key.hashCode() + "=" + value);
return value;
}
@Override
public Object removeObject(Object key) {
Jedis jedis = null;
JedisPool jedisPool = null;
Object value = null;
boolean borrowOrOprSuccess = true;
try {
jedis = CachePool.getInstance().getJedis();
jedisPool = CachePool.getInstance().getJedisPool();
value = jedis.expire(SerializeUtil.serialize(key.hashCode()), 0);
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
jedisPool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
jedisPool.returnResource(jedis);
}
if(log.isDebugEnabled())
log.debug("getObject:" + key.hashCode() + "=" + value);
return value;
}
@Override
public void clear() {
Jedis jedis = null;
JedisPool jedisPool = null;
boolean borrowOrOprSuccess = true;
try {
jedis = CachePool.getInstance().getJedis();
jedisPool = CachePool.getInstance().getJedisPool();
jedis.flushDB();
jedis.flushAll();
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
jedisPool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
jedisPool.returnResource(jedis);
}
}
@Override
public ReadWriteLock getReadWriteLock() {
return readWriteLock;
}
/**
*
* @ClassName: CachePool
* @Description: TODO(单例Cache池)
* @author LiuYi
* @date 2014年6月17日 上午10:50:52
*
*/
public static class CachePool {
JedisPool pool;
private static final CachePool cachePool = new CachePool();
public static CachePool getInstance(){
return cachePool;
}
private CachePool() {
JedisPoolConfig config = new JedisPoolConfig();
config.setMaxIdle(100);
config.setMaxWaitMillis(1000l);
PropertiesLoader pl = new PropertiesLoader("classpath:config/redis.properties");
pool = new JedisPool(config,pl.getProperty("redisvip"));
}
public Jedis getJedis(){
Jedis jedis = null;
boolean borrowOrOprSuccess = true;
try {
jedis = pool.getResource();
} catch (JedisConnectionException e) {
borrowOrOprSuccess = false;
if (jedis != null)
pool.returnBrokenResource(jedis);
} finally {
if (borrowOrOprSuccess)
pool.returnResource(jedis);
}
jedis = pool.getResource();
return jedis;
}
public JedisPool getJedisPool(){
return this.pool;
}
}
public static 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) {
if(bytes == null)return null;
ByteArrayInputStream bais = null;
try {
// 反序列化
bais = new ByteArrayInputStream(bytes);
ObjectInputStream ois = new ObjectInputStream(bais);
return ois.readObject();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
}参考链接：http://liuyieyer.iteye.com/blog/2081382
来源：oschina
链接：https://my.oschina.net/u/123050/blog/607436