com.sicheng.common.persistence.cache.MybatisEhcache Maven / Gradle / Ivy
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* 本作品使用 木兰公共许可证,第2版（Mulan PubL v2） 开源协议，请遵守相关条款，或者联系sicheng.net获取商用授权。
* Copyright (c) 2016 SiCheng.Net
* This software is licensed under Mulan PubL v2.
* You can use this software according to the terms and conditions of the Mulan PubL v2.
* You may obtain a copy of Mulan PubL v2 at:
* http://license.coscl.org.cn/MulanPubL-2.0
* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
* See the Mulan PubL v2 for more details.
*/
package com.sicheng.common.persistence.cache;
import com.sicheng.common.utils.ObjectUtils;
import net.sf.ehcache.CacheManager;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import org.apache.ibatis.cache.Cache;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.concurrent.locks.ReadWriteLock;
/**
* 标题: Mybatis二级缓存的Ehcache实现
* 描述: shop使用了Mybatis二级缓存，来提高系统的性能，降低数据库的读取压力。缓存的实现是Ehcache
* 公司: 思程科技 www.sicheng.net
*
* @author zhaolei
* @date 2017年7月5日 下午6:35:47
*/
public final class MybatisEhcache implements SecondLevelCache {
private static Logger logger = LoggerFactory.getLogger(MybatisEhcache.class);
private boolean safe = true;//开头，返回的是对象的复本，通过序列化实现的克隆，可防止潜在的修改风险
/**
* 当不需要锁时，请使用本虚假锁，来达到无锁的目的
* As of 3.2.6 MyBatis does not call locking methods.
*/
private final ReadWriteLock readWriteLock = new DummyReadWriteLock();
/**
* 命名空间、缓存id、缓存的分区
*/
private String id;
/**
* 缓存有效期，单位：秒，默认值2天
*/
private int expire = 172800;
/**
* Ehcache的客户端 ，spring静态注入
*/
private CacheManager cacheManager;
/**
* @return the cacheManager
*/
public CacheManager getCacheManager() {
return cacheManager;
}
/**
* @param cacheManager the cacheManager to set
*/
public void setCacheManager(CacheManager cacheManager) {
this.cacheManager = cacheManager;
}
/**
* Ehcache的客户端
*/
private Ehcache cache;
/**
* @Title:构造方法
* @Description:spring容器需要一个无参的构造方法
*/
public MybatisEhcache() {
}
/**
* 初始化
*
* @param id 设置缓存分区的name
* @param expire 设置缓存的有效期 （单位：秒）
*/
public void init(String id, int expire) {
if (id == null) {
throw new IllegalArgumentException("Cache instances require an ID");
}
this.expire = expire;
this.id = id;
if (!cacheManager.cacheExists(id)) {
cacheManager.addCache(id);
}
this.cache = cacheManager.getCache(id);
setTimeToIdleSeconds(expire);//设置缓存的有效期
}
/**
*
* 清除此缓存实例
* 清除Redis服务器当前数据库中所有的数据
*
*
* @see org.apache.ibatis.cache.Cache#clear()
*/
public void clear() {
long t1 = System.currentTimeMillis();
cache.removeAll();
long t2 = System.currentTimeMillis();
if (logger.isDebugEnabled()) {
logger.debug("Mybatis二级缓存-ehcache clear,id={},{}ms", id, (t2 - t1));
}
}
/**
* 描述: getId
*
* @return
* @see org.apache.ibatis.cache.Cache#getId()
*/
public String getId() {
return this.id;
}
/**
* 获取对象
*
* @param key
* @return
* @see org.apache.ibatis.cache.Cache#getObject(java.lang.Object)
*/
public Object getObject(Object key) {
if (key == null) {
return null;
}
if (cache == null) {
return null;
}
long t1 = System.currentTimeMillis();
Element cachedElement = cache.get(CacheKeyUtils.creadkey(key));
if (cachedElement == null) {
return null;
}
Object v = cachedElement.getObjectValue();
long t2 = System.currentTimeMillis();
if (logger.isDebugEnabled()) {
logger.debug("Mybatis二级缓存-ehcache getObject,key={},{}ms", CacheKeyUtils.creadkey(key), (t2 - t1));
}
if (safe) {
return ObjectUtils.unserialize((byte[]) v);
} else {
return v;
}
}
/**
*
* 在3.2.6以后，本方法不再被核心调用
* 缓存所需的任何锁，必须由缓存程序内部自行提供。
*
*
* @return
* @see org.apache.ibatis.cache.Cache#getReadWriteLock()
*/
public ReadWriteLock getReadWriteLock() {
return readWriteLock;
}
/**
*
* 可选。这个方法不被core调用
* 获取当前Redis服务器当前数据库中缓存的key的数量
*
*
* @return
* @see org.apache.ibatis.cache.Cache#getSize()
*/
public int getSize() {
return cache.getSize();
}
/**
* 放入对象
*
* @param key
* @param value
* @see org.apache.ibatis.cache.Cache#putObject(java.lang.Object, java.lang.Object)
*/
public void putObject(Object key, Object value) {
long t1 = System.currentTimeMillis();
if (safe) {
value = ObjectUtils.serialize(value);
}
cache.put(new Element(CacheKeyUtils.creadkey(key), value));
long t2 = System.currentTimeMillis();
if (logger.isDebugEnabled()) {
logger.debug("Mybatis二级缓存-ehcache putObject,key={},expire={},{}ms", CacheKeyUtils.creadkey(key), expire, (t2 - t1));
}
}
/**
*
* 删除对象. 从3.3.0，此方法只在回滚时调用
*
*
* @param key
* @return
* @see org.apache.ibatis.cache.Cache#removeObject(java.lang.Object)
*/
public Object removeObject(Object key) {
long t1 = System.currentTimeMillis();
Object obj = getObject(CacheKeyUtils.creadkey(key));
cache.remove(CacheKeyUtils.creadkey(key));
long t2 = System.currentTimeMillis();
if (logger.isDebugEnabled()) {
logger.debug("Mybatis二级缓存-ehcache removeObject,key={},{}ms", CacheKeyUtils.creadkey(key), (t2 - t1));
}
return obj;
}
/**
* {@inheritDoc}
*/
@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 id.equals(otherCache.getId());
}
/**
* {@inheritDoc}
*/
@Override
public int hashCode() {
return id.hashCode();
}
/**
* {@inheritDoc}
*/
@Override
public String toString() {
return "EHCache {" + id + "}";
}
// DYNAMIC PROPERTIES
/**
* Sets the time to idle for an element before it expires. Is only used if the element is not eternal.
*
* @param timeToIdleSeconds the default amount of time to live for an element from its last accessed or modified date
*/
public void setTimeToIdleSeconds(long timeToIdleSeconds) {
cache.getCacheConfiguration().setTimeToIdleSeconds(timeToIdleSeconds);
}
/**
* Sets the time to idle for an element before it expires. Is only used if the element is not eternal.
*
* @param timeToLiveSeconds the default amount of time to live for an element from its creation date
*/
public void setTimeToLiveSeconds(long timeToLiveSeconds) {
cache.getCacheConfiguration().setTimeToLiveSeconds(timeToLiveSeconds);
}
/**
* Sets the maximum objects to be held in memory (0 = no limit).
*
* @param maxElementsInMemory The maximum number of elements in memory, before they are evicted (0 == no limit)
*/
public void setMaxEntriesLocalHeap(long maxEntriesLocalHeap) {
cache.getCacheConfiguration().setMaxEntriesLocalHeap(maxEntriesLocalHeap);
}
/**
* Sets the maximum number elements on Disk. 0 means unlimited.
*
* @param maxElementsOnDisk the maximum number of Elements to allow on the disk. 0 means unlimited.
*/
public void setMaxEntriesLocalDisk(long maxEntriesLocalDisk) {
cache.getCacheConfiguration().setMaxEntriesLocalDisk(maxEntriesLocalDisk);
}
/**
* Sets the eviction policy. An invalid argument will set it to null.
*
* @param memoryStoreEvictionPolicy a String representation of the policy. One of "LRU", "LFU" or "FIFO".
*/
public void setMemoryStoreEvictionPolicy(String memoryStoreEvictionPolicy) {
cache.getCacheConfiguration().setMemoryStoreEvictionPolicy(memoryStoreEvictionPolicy);
}
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