mybatis 项目配置文件实例详解
(编辑:jimmy 日期: 2024/12/24 浏览:3 次 )
mybatis项目配置
首先这事一个简单的mybatis项目配置文件:
<"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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