Mybatis project configuration file instance details, mybatis configuration file

Mybatis project configuration file instance details, mybatis configuration file

Mybatis project configuration

First, this is a simple mybatis project configuration file:

<?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 supports multiple environments and can be configured as needed

For example:

 <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>

There will be two environments. Which one is selected for the defalut tag in environments and which one is selected by default?

TransactionManager

Mybatis supports two types of transaction managers: jdbc and managed)

Jdbc: application management database connection Lifecycle

Managed: The application server is responsible for managing the lifecycle of database connections (this function is generally available on commercial servers, such as JBOSS WebLogic)

DataSource

Type: used to configure the data source. The data types include UNPOOLED, POOLED, and JNDI.

UNPOOLED: No connection pool. Every database operation, mybatis creates a new connection. After the connection is used up, it is closed: suitable for small concurrent projects.

POOLED: With connection pool

JNDI: Use the application server to configure the JNDI data source to obtain the database connection

Properties

Configure attributes

For example:

<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

Alias for the complete qualified name of the class for ease of use

For example:

<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> <! -- Most commonly used --> <typeAliases> <package name = "domain. blog"/> </typeAliases>

Mappers

Introduce a ing File

<!-- 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

Plug-ins such:

Paging plug-in

<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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