1、加入以下依赖包
2、配置ehcache.xml
<?xml version="1.0" encoding="UTF-8"?>
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">
<!-- 磁盘保存路径 -->
<diskStore path="D:\44\ehcache" />
<defaultCache
maxElementsInMemory="10000"
maxElementsOnDisk="10000000"
eternal="false"
overflowToDisk="true"
timeToIdleSeconds="120"
timeToLiveSeconds="120"
diskExpiryThreadIntervalSeconds="120"
memoryStoreEvictionPolicy="LRU">
</defaultCache>
</ehcache>
<!--
属性说明:
l diskStore:指定数据在磁盘中的存储位置。
l defaultCache:当借助CacheManager.add("demoCache")创建Cache时,EhCache便会采用<defalutCache/>指定的的管理策略
以下属性是必须的:
l maxElementsInMemory - 在内存中缓存的element的最大数目
l maxElementsOnDisk - 在磁盘上缓存的element的最大数目,若是0表示无穷大
l eternal - 设定缓存的elements是否永远不过期。如果为true,则缓存的数据始终有效,如果为false那么还要根据timeToIdleSeconds,timeToLiveSeconds判断
l overflowToDisk - 设定当内存缓存溢出的时候是否将过期的element缓存到磁盘上
以下属性是可选的:
l timeToIdleSeconds - 当缓存在EhCache中的数据前后两次访问的时间超过timeToIdleSeconds的属性取值时,这些数据便会删除,默认值是0,也就是可闲置时间无穷大
l timeToLiveSeconds - 缓存element的有效生命期,默认是0.,也就是element存活时间无穷大
diskSpoolBufferSizeMB 这个参数设置DiskStore(磁盘缓存)的缓存区大小.默认是30MB.每个Cache都应该有自己的一个缓冲区.
l diskPersistent - 在VM重启的时候是否启用磁盘保存EhCache中的数据,默认是false。
l diskExpiryThreadIntervalSeconds - 磁盘缓存的清理线程运行间隔,默认是120秒。每个120s,相应的线程会进行一次EhCache中数据的清理工作
l memoryStoreEvictionPolicy - 当内存缓存达到最大,有新的element加入的时候, 移除缓存中element的策略。默认是LRU(最近最少使用),可选的有LFU(最不常使用)和FIFO(先进先出)
-->
3、在mapper.xml中使用
<mapper namespace="com.gong.mybatis.dao.EmployeeMapper">
<cache type="org.mybatis.caches.ehcache.EhcacheCache"></cache>
......
</mapper>
4、也可以在其它mapper.xml中引用配置好缓存的mapper
<mapper namespace="com.gong.mybatis.dao.DepartmentMapper">
<cache-ref namespace="com.gong.mybatis.dao.EmployeeMapper"/>
......
</mapper>
最后进行测试二级缓存:
package com.gong.mybatis.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import com.gong.mybatis.bean.Department;
import com.gong.mybatis.bean.Employee;
import com.gong.mybatis.dao.EmployeeMapper;
import com.gong.mybatis.mapper.EmployeeMapperDynamicSql;
public class TestMybatis4 {
public SqlSessionFactory getSqlSessionFactory() throws IOException {
String resource = "mybatis-config.xml";
InputStream is = Resources.getResourceAsStream(resource);
return new SqlSessionFactoryBuilder().build(is);
}
@Test
public void test() throws IOException {
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession openSession = sqlSessionFactory.openSession();
SqlSession openSession2 = sqlSessionFactory.openSession();
try {
EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
EmployeeMapper mapper2 = openSession2.getMapper(EmployeeMapper.class);
Employee em = mapper.getEmpById(1);
System.out.println(em);
openSession.close();
Employee em2 = mapper2.getEmpById(1);
System.out.println(em2);
openSession.close();
} finally {
// TODO: handle finally clause
}
}
}
输出:
DEBUG 01-22 11:31:12,291 Configuring ehcache from ehcache.xml found in the classpath: file:/F:/ssmwork/mybatis/bin/ehcache.xml (ConfigurationFactory.java:132)
DEBUG 01-22 11:31:12,307 Configuring ehcache from URL: file:/F:/ssmwork/mybatis/bin/ehcache.xml (ConfigurationFactory.java:98)
DEBUG 01-22 11:31:12,307 Configuring ehcache from InputStream (ConfigurationFactory.java:150)
DEBUG 01-22 11:31:12,417 Ignoring ehcache attribute xmlns:xsi (BeanHandler.java:271)
DEBUG 01-22 11:31:12,417 Ignoring ehcache attribute xsi:noNamespaceSchemaLocation (BeanHandler.java:271)
DEBUG 01-22 11:31:12,417 Disk Store Path: D:\44\ehcache (DiskStoreConfiguration.java:141)
DEBUG 01-22 11:31:12,448 Creating new CacheManager with default config (CacheManager.java:1036)
DEBUG 01-22 11:31:12,464 propertiesString is null. (PropertyUtil.java:88)
DEBUG 01-22 11:31:12,479 No CacheManagerEventListenerFactory class specified. Skipping... (ConfigurationHelper.java:185)
DEBUG 01-22 11:31:13,072 No BootstrapCacheLoaderFactory class specified. Skipping... (Cache.java:955)
DEBUG 01-22 11:31:13,072 CacheWriter factory not configured. Skipping... (Cache.java:929)
DEBUG 01-22 11:31:13,072 No CacheExceptionHandlerFactory class specified. Skipping... (ConfigurationHelper.java:96)
DEBUG 01-22 11:31:13,119 Initialized net.sf.ehcache.store.MemoryStore for com.gong.mybatis.dao.EmployeeMapper (MemoryStore.java:152)
DEBUG 01-22 11:31:13,181 Using diskstore path D:\44\ehcache (DiskStorePathManager.java:169)
DEBUG 01-22 11:31:13,181 Holding exclusive lock on D:\44\ehcache\.ehcache-diskstore.lock (DiskStorePathManager.java:170)
DEBUG 01-22 11:31:13,197 Failed to delete file com%002egong%002emybatis%002edao%002e%0045mployee%004dapper.data (DiskStorageFactory.java:860)
DEBUG 01-22 11:31:13,197 Failed to delete file com%002egong%002emybatis%002edao%002e%0045mployee%004dapper.index (DiskStorageFactory.java:860)
DEBUG 01-22 11:31:13,696 Matching data file missing (or empty) for index file. Deleting index file D:\44\ehcache\com%002egong%002emybatis%002edao%002e%0045mployee%004dapper.index (DiskStorageFactory.java:168)
DEBUG 01-22 11:31:13,712 Failed to delete file com%002egong%002emybatis%002edao%002e%0045mployee%004dapper.index (DiskStorageFactory.java:860)
DEBUG 01-22 11:31:13,759 Initialised cache: com.gong.mybatis.dao.EmployeeMapper (Cache.java:1165)
DEBUG 01-22 11:31:13,759 CacheDecoratorFactory not configured for defaultCache. Skipping for 'com.gong.mybatis.dao.EmployeeMapper'. (ConfigurationHelper.java:354)
DEBUG 01-22 11:31:13,907 Cache Hit Ratio [com.gong.mybatis.dao.EmployeeMapper]: 0.0 (LoggingCache.java:62)
DEBUG 01-22 11:31:14,360 ==> Preparing: select id,last_name lastName,email,gender from tbl_employee where id = ? (BaseJdbcLogger.java:145)
DEBUG 01-22 11:31:14,391 ==> Parameters: 1(Integer) (BaseJdbcLogger.java:145)
DEBUG 01-22 11:31:14,453 <== Total: 1 (BaseJdbcLogger.java:145)
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
DEBUG 01-22 11:31:14,453 put added 0 on heap (Segment.java:425)
DEBUG 01-22 11:31:14,469 Cache Hit Ratio [com.gong.mybatis.dao.EmployeeMapper]: 0.5 (LoggingCache.java:62)
Employee [id=1, lastName=dema, gender=1, email=dema@qq.com, dept=null]
DEBUG 01-22 11:31:14,484 fault removed 0 from heap (Segment.java:779)
DEBUG 01-22 11:31:14,484 fault added 0 on disk (Segment.java:796)
说明配置成功。