mybatis 项目配置文件实例详解
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2022-03-07 12:24:06
mybatis项目配置
首先这事一个简单的mybatis项目配置文件：
mybatis项目配置
首先这事一个简单的mybatis项目配置文件：
<?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>
<environments default="development">
<environment id="development">
<transactionmanager type="jdbc"/>
<datasource type="pooled">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</datasource>
</environment>
</environments>
<mappers>
<mapper resource="org/mybatis/example/blogmapper.xml"/>
</mappers>
</configuration>
environment
mybatis支持多个环境，可以任意配置
比如：
<environments default="development">
<environment id="development">
<transactionmanager type="jdbc"/>
<datasource type="pooled">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</datasource>
</environment>
<environment id="test">
<transactionmanager type="jdbc"/>
<datasource type="pooled">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</datasource>
</environment>
</environments>
就会有两个环境，environments中的defalut标签选择哪一个，默认就是哪一个
transactionmanager
mybatis支持两种类型的事务管理器，jdbc和managed（托管）
jdbc：应用程序管理数据库连接的生命周期
managed：由应用服务器负责管理数据库连接的生命周期（一般商业服务器才有此功能，如jboss weblogic）
datasource
type：用来配置数据源，类型有：unpooled、pooled、jndi
unpooled：没有连接池，每次数据库操作，mybatis都会创建一个新的连接，用完后，关闭：适合小并发项目
pooled：有连接池
jndi：使用应用服务器配置jndi数据源获取数据库连接
properties
配置属性
比如：
<properties resource="org/mybatis/example/config.properties">
<property name="username" value="dev_user"/>
<property name="password" value="f2fa3!33tyyg"/>
</properties>
<datasource type="pooled">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</datasource>
typealiases
给类的完整限定名取别名，方便使用
比如：
<typealiases> <typealias alias="author" type="domain.blog.author"/> <typealias alias="blog" type="domain.blog.blog"/> <typealias alias="comment" type="domain.blog.comment"/> <typealias alias="post" type="domain.blog.post"/> <typealias alias="section" type="domain.blog.section"/> <typealias alias="tag" type="domain.blog.tag"/> </typealiases> <!-- 最常用--> <typealiases> <package name="domain.blog"/> </typealiases>
mappers
引入映射文件
<!-- using classpath relative resources --> <mappers> <mapper resource="org/mybatis/builder/authormapper.xml"/> <mapper resource="org/mybatis/builder/blogmapper.xml"/> <mapper resource="org/mybatis/builder/postmapper.xml"/> </mappers> <!-- using url fully qualified paths --> <mappers> <mapper url="file:///var/mappers/authormapper.xml"/> <mapper url="file:///var/mappers/blogmapper.xml"/> <mapper url="file:///var/mappers/postmapper.xml"/> </mappers> <!-- using mapper interface classes --> <mappers> <mapper class="org.mybatis.builder.authormapper"/> <mapper class="org.mybatis.builder.blogmapper"/> <mapper class="org.mybatis.builder.postmapper"/> </mappers> <!-- register all interfaces in a package as mappers --> <mappers> <package name="org.mybatis.builder"/> </mappers>
settings
an example of the settings element fully configured is as follows:
<settings> <setting name="cacheenabled" value="true"/> <setting name="lazyloadingenabled" value="true"/> <setting name="multipleresultsetsenabled" value="true"/> <setting name="usecolumnlabel" value="true"/> <setting name="usegeneratedkeys" value="false"/> <setting name="automappingbehavior" value="partial"/> <setting name="automappingunknowncolumnbehavior" value="warning"/> <setting name="defaultexecutortype" value="simple"/> <setting name="defaultstatementtimeout" value="25"/> <setting name="defaultfetchsize" value="100"/> <setting name="saferowboundsenabled" value="false"/> <setting name="mapunderscoretocamelcase" value="false"/> <setting name="localcachescope" value="session"/> <setting name="jdbctypefornull" value="other"/> <setting name="lazyloadtriggermethods" value="equals,clone,hashcode,tostring"/> </settings>
plugins
插件 比如：
分页插件
<plugins>
<plugin interceptor="com.github.pagehelper.pagehelper">
<property name="dialect" value="mysql"/>
<property name="offsetaspagenum" value="true"/>
<property name="rowboundswithcount" value="true"/>
<property name="pagesizezero" value="true"/>
</plugin>
</plugins>
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