import java.io.BufferedReader;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.UnsupportedEncodingException;import java.util.Properties;import java.util.Set;import java.util.concurrent.locks.ReadWriteLock;import java.util.concurrent.locks.ReentrantReadWriteLock; import org.apache.commons.codec.digest.DigestUtils;import org.apache.ibatis.cache.Cache;import org.apache.log4j.Logger;import redis.clients.jedis.Jedis; /* * 使用第三方缓存服务器，处理二级缓存 * zuimao */public class RedisCache implements Cache {         private static final Logger logger = Logger.getLogger(RedisCache.class);         /** The ReadWriteLock. */    private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();     private final String COMMON_CACHE_KEY = "MYBATIS:";    private static final String UTF_8 = "utf-8";      /**     * 按照一定规则标识key     */    private String getKey(Object key) {        StringBuilder accum = new StringBuilder();        accum.append(COMMON_CACHE_KEY);        accum.append(this.id).append(":");        accum.append(DigestUtils.md5Hex(String.valueOf(key)));        return accum.toString();    }      /**     * redis key规则前缀     */    private String getKeys() {        return COMMON_CACHE_KEY + this.id + ":*";    }     private String id;      public RedisCache() {    }     public RedisCache(final String id) {        if (id == null) {            throw new IllegalArgumentException("必须传入ID");        }        logger.debug("MybatisRedisCache:id=" + id);        this.id = id;    }     @Override    public String getId() {        return this.id;    }     @Override    public int getSize() {        Jedis jedis = null;        int result = 0;        try {            jedis = RedisStandAloneUtil.getJedisPool().getResource();            Set<byte[]> keys = jedis.keys(getKeys().getBytes(UTF_8));            if (null != keys && !keys.isEmpty()) {                result = keys.size();            }            logger.debug(this.id+"---->>>>总缓存数:" + result);        } catch (Exception e) {        	 logger.error(e.getMessage(), e);        } finally {        	if (jedis != null) {                jedis.close();            }                    }        return result;    }     @Override    public void putObject(Object key, Object value) {        Jedis jedis = null;        try {            jedis = RedisStandAloneUtil.getJedisPool().getResource();                         byte[] keys = getKey(key).getBytes(UTF_8);            jedis.set(keys, SerializeUtil.serialize(value));            logger.debug("添加缓存--------"+this.id);            //getSize();        } catch (Exception e) {            logger.error(e.getMessage(), e);        } finally {            if (jedis != null) {                jedis.close();            }        }     }     @Override    public Object getObject(Object key) {        Jedis jedis = null;        Object value = http://www.mamicode.com/null;"从缓存中获取-----"+this.id);            //getSize();        } catch (Exception e) {            logger.error(e.getMessage(), e);        } finally {            if (jedis != null) {                jedis.close();            }        }        return value;    }     @Override    public Object removeObject(Object key) {        Jedis jedis = null;        Object value = http://www.mamicode.com/null;"LRU算法从缓存中移除-----"+this.id);            //getSize();        } catch (Exception e) {            logger.error(e.getMessage(), e);        } finally {            if (jedis != null) {                jedis.close();            }        }        return value;    }     @Override    public void clear() {        Jedis jedis = null;        try {        	jedis = RedisStandAloneUtil.getJedisPool().getResource();            Set<byte[]> keys = jedis.keys(getKeys().getBytes(UTF_8));            logger.debug("出现CUD操作，清空对应Mapper缓存======>"+keys.size());            for (byte[] key : keys) {                jedis.del(key);            }            //下面是网上流传的方法，极大的降低系统性能，没起到加入缓存应有的作用，这是不可取的。            //jedis.flushDB();            //jedis.flushAll();        } catch (Exception e) {            logger.error(e.getMessage(), e);        } finally {            if (jedis != null) {                jedis.close();            }        }    }     @Override    public ReadWriteLock getReadWriteLock() {        return readWriteLock;    }     }