核心配置文件常用配置标签

properties标签：该标签可以加载外部的properties文件

<properties resource="jdbc.properties"></properties>

typeAliases标签：设置类型别名

<typeAlias type="com.juanxincai.domain.User" alias="user"></typeAlias>

mappers标签：加载映射配置

<mapper resource="com/juanxincai/mapper/UserMapping.xml"></mapper>

environments标签：数据源环境配置标签

    <environments default="development">        
        <environment id="development">            
            <transactionManager type="JDBC"/>            
            <dataSource type="POOLED">                
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql:///test"/>                
                <property name="username" value="root"/>
                <property name="password" value="root"/>            
            </dataSource>        
        </environment>    
    </environments>