配置

mybatis提供了3种配置方式
一：property子元素
二：properties配置文件
三：程序参数传递

一：property子元素

<configuration>
    <properties >
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </properties>
    <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>

二：properties配置文件
<configuration>
    <properties resource="db.properties">
        <property name="driver" value="driver"/>
        <property name="url" value="url"/>
        <property name="username" value="username"/>
        <property name="password" value="password"/>
    </properties>
    <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="com/nbg/dao/UserMapper.xml"/>
    </mappers>
</configuration>

三：