mybatis缓存文件的配置

在java程序运行过程中，每次调用都会访问数据库吗？答案是否定的，java会有缓存将访问过的存起来下次调用时就不在连接数据库了，而是从缓存中找。

mybatis缓存详细：http://blog.csdn.net/marvel__dead/article/details/70133715   引用别人的，写的挺好

下面是我自己的测试：

一.配置文件的写法

log4 相关包是为了测试用的，主要在控制台显示程序的进程。ehcache 和 mybatis-ehcache是俩个mybatis的缓存包，外部缓存需要添加的jar包

步骤如下：

1.配置文件： conf.xml          usermapper.xml

2. conf.xml 第四行的setting标签，启用缓存（外部缓存和二级缓存都需要）

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><settings>   <setting name="cacheEnabled" value="true"/></settings>    <environments default="development">        <environment id="development">            <transactionManager type="JDBC" />            <!-- 配置数据库连接信息 -->            <dataSource type="POOLED">                <property name="driver" value="com.mysql.jdbc.Driver" />                <property name="url" value="jdbc:mysql://localhost:3306/luntan" />                <property name="username" value="root" />                <property name="password" value="mysql" />            </dataSource>        </environment>    </environments>    <mappers>       <mapper resource="it/com/mapper/UserMapper.xml"/>         </mappers>    </configuration>

3.缓存只有select有，所以那条select使用缓存，记得在标签里将 userCache改成true

    同时配置cache标签，下面代码使用的是外部缓存，被注释的是二级缓存，里面的配置标签property  ehcache.xml文件中有，外部缓存会jar包会自动调用

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="it.com.dao"><!-- 缓存配置  --> <cache type="org.mybatis.caches.ehcache.LoggingEhcache"><!-- <cache type="org.mybatis.caches.ehcache.EhcacheCache">  -->         <property name="timeToIdleSeconds" value="3600"/><!--1 hour-->        <property name="timeToLiveSeconds" value="3600"/><!--1 hour-->        <property name="maxEntriesLocalHeap" value="10000"/>        <property name="maxEntriesLocalDisk" value="10000000"/>    </cache>   <select id="findall" resultType="Map" useCache="true"><!-- 使用缓存 -->      select * from users   </select>   <select id="findById" resultType="Map" parameterType="String" useCache="true">      select * from users where userName = #{userName}   </select>   <select id="findByIdPwd" resultType="Map" parameterType="Map">      select * from users where userName = #{userName} and userPwd=#{userPwd}   </select>   <insert id="insertByIdPwd" parameterType="Map">      insert into users(userName,userPwd) values (#{userName},#{userPwd})   </insert></mapper>

4.在userDao中调用方法

public List<Map> findById(String userName){List<Map> list=null;SqlSession session = SF.getSession();list=session.selectList("findById",userName);session.commit();//使用缓存必须写return list;}

测试结果：

DEBUG - Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - Configuring ehcache from ehcache.xml found in the classpath: file:/F:/myeclipse%20%20workspace/test08021/WebRoot/WEB-INF/classes/ehcache.xmlDEBUG - Configuring ehcache from URL: file:/F:/myeclipse%20%20workspace/test08021/WebRoot/WEB-INF/classes/ehcache.xmlDEBUG - Configuring ehcache from InputStreamDEBUG - Disk Store Path: F:\ehcache111DEBUG - Creating new CacheManager with default configDEBUG - propertiesString is null.DEBUG - No CacheManagerEventListenerFactory class specified. Skipping...DEBUG - No BootstrapCacheLoaderFactory class specified. Skipping...DEBUG - CacheWriter factory not configured. Skipping...DEBUG - No CacheExceptionHandlerFactory class specified. Skipping...DEBUG - Initialized net.sf.ehcache.store.MemoryStore for it.com.daoWARN - diskStorePath 'F:\ehcache111' is already used by an existing CacheManager either in the same VM or in a different process.The diskStore path for this CacheManager will be set to F:\ehcache111\ehcache_auto_created7300060912575425752diskstore.To avoid this warning consider using the CacheManager factory methods to create a singleton CacheManager or specifying a separate ehcache configuration (ehcache.xml) for each CacheManager instance.DEBUG - Using diskstore path F:\ehcache111\ehcache_auto_created7300060912575425752diskstoreDEBUG - Holding exclusive lock on F:\ehcache111\ehcache_auto_created7300060912575425752diskstore\.ehcache-diskstore.lockDEBUG - Failed to delete file it%002ecom%002edao.dataDEBUG - Failed to delete file it%002ecom%002edao.indexDEBUG - Matching data file missing (or empty) for index file. Deleting index file F:\ehcache111\ehcache_auto_created7300060912575425752diskstore\it%002ecom%002edao.indexDEBUG - Failed to delete file it%002ecom%002edao.indexDEBUG - Initialised cache: it.com.daoDEBUG - CacheDecoratorFactory not configured for defaultCache. Skipping for 'it.com.dao'.DEBUG - Cache Hit Ratio [it.com.dao]: 0.0DEBUG - Opening JDBC ConnectionDEBUG - Created connection 1763371495.DEBUG - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.Connection@691ae9e7]DEBUG - ooo Using Connection [com.mysql.jdbc.Connection@691ae9e7]DEBUG - ==>  Preparing: select * from users where userName = ? DEBUG - ==> Parameters: admire(String)TRACE - <==    Columns: userName, userPwd, Ename, Email, Logo, userIdTRACE - <==        Row: admire, 111111, 1111, 11111, 12, 1DEBUG - <==      Total: 1DEBUG - put added 0 on heap[{Email=11111, Ename=1111, Logo=12, userId=1, userPwd=111111, userName=admire}]DEBUG - fault removed 0 from heapDEBUG - fault added 0 on diskDEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.[{Email=11111, Ename=1111, Logo=12, userId=1, userPwd=111111, userName=admire}]DEBUG - Cache Hit Ratio [it.com.dao]: 1.0DEBUG - remove deleted 0 from heapDEBUG - remove deleted 0 from disk

二.注解的写法

注解的写法就相对简单了，只需要在接口文件中

package it.com.db;import java.util.List;import java.util.Map;import org.apache.ibatis.annotations.CacheNamespace;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Options;import org.apache.ibatis.annotations.Param;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.cache.decorators.LruCache;//配置缓存@CacheNamespace(size=100,eviction=LruCache.class,implementation=org.mybatis.caches.ehcache.EhcacheCache.class)public interface IUsersMapper {//打开缓存@Options(useCache=true)@Select("select * from users")public List<Map> findAll();@Select("select count(1) from users where userName=#{userName}")public int findById(@Param("userName") String userName);//存储过程@Select("call pp11()")public List<Map> findAll_a();}

测试结果：

public int findById(String userName){SqlSession session = SF.getSession();IUsersMapper um = session.getMapper(IUsersMapper.class);int n = um.findById(userName);session.commit();return n;}

public static void main(String[] args) {// TODO Auto-generated method stubUsersDao user = new UsersDao();System.out.println(user.findById("admire"));System.out.println(user.findById("admire"));}

DEBUG - Logging initialized using 'class org.apache.ibatis.logging.slf4j.Slf4jImpl' adapter.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - Configuring ehcache from ehcache.xml found in the classpath: file:/F:/myeclipse%20%20workspace/test08021/WebRoot/WEB-INF/classes/ehcache.xmlDEBUG - Configuring ehcache from URL: file:/F:/myeclipse%20%20workspace/test08021/WebRoot/WEB-INF/classes/ehcache.xmlDEBUG - Configuring ehcache from InputStreamDEBUG - Disk Store Path: F:\ehcache111DEBUG - Creating new CacheManager with default configDEBUG - propertiesString is null.DEBUG - No CacheManagerEventListenerFactory class specified. Skipping...DEBUG - No BootstrapCacheLoaderFactory class specified. Skipping...DEBUG - CacheWriter factory not configured. Skipping...DEBUG - No CacheExceptionHandlerFactory class specified. Skipping...DEBUG - Initialized net.sf.ehcache.store.MemoryStore for it.com.daoWARN - diskStorePath 'F:\ehcache111' is already used by an existing CacheManager either in the same VM or in a different process.The diskStore path for this CacheManager will be set to F:\ehcache111\ehcache_auto_created7300060912575425752diskstore.To avoid this warning consider using the CacheManager factory methods to create a singleton CacheManager or specifying a separate ehcache configuration (ehcache.xml) for each CacheManager instance.DEBUG - Using diskstore path F:\ehcache111\ehcache_auto_created7300060912575425752diskstoreDEBUG - Holding exclusive lock on F:\ehcache111\ehcache_auto_created7300060912575425752diskstore\.ehcache-diskstore.lockDEBUG - Failed to delete file it%002ecom%002edao.dataDEBUG - Failed to delete file it%002ecom%002edao.indexDEBUG - Matching data file missing (or empty) for index file. Deleting index file F:\ehcache111\ehcache_auto_created7300060912575425752diskstore\it%002ecom%002edao.indexDEBUG - Failed to delete file it%002ecom%002edao.indexDEBUG - Initialised cache: it.com.daoDEBUG - CacheDecoratorFactory not configured for defaultCache. Skipping for 'it.com.dao'.DEBUG - Cache Hit Ratio [it.com.dao]: 0.0DEBUG - Opening JDBC ConnectionDEBUG - Created connection 1763371495.DEBUG - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.Connection@691ae9e7]DEBUG - ooo Using Connection [com.mysql.jdbc.Connection@691ae9e7]DEBUG - ==>  Preparing: select * from users where userName = ? DEBUG - ==> Parameters: admire(String)TRACE - <==    Columns: userName, userPwd, Ename, Email, Logo, userIdTRACE - <==        Row: admire, 111111, 1111, 11111, 12, 1DEBUG - <==      Total: 1DEBUG - put added 0 on heap[{Email=11111, Ename=1111, Logo=12, userId=1, userPwd=111111, userName=admire}]DEBUG - fault removed 0 from heapDEBUG - fault added 0 on diskDEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.DEBUG - PooledDataSource forcefully closed/removed all connections.[{Email=11111, Ename=1111, Logo=12, userId=1, userPwd=111111, userName=admire}]DEBUG - Cache Hit Ratio [it.com.dao]: 1.0DEBUG - remove deleted 0 from heapDEBUG - remove deleted 0 from disk