mybatis 项目配置文件实例详解
作者：gefufeng
这篇文章主要介绍了mybatis 项目配置文件实例详解的相关资料,需要的朋友可以参考下
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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