mybatis-config.xml
<mappers>
    <!--方式一-->
 <!--   <mapper class="cn.itcast.mapper.UserMapper"/>-->
    <!--方式二-->
 <!--   <mapper resource="UserMapper.xml"/>-->
    <!--方式三-->
    <package name="cn.itcast.mapper"/>
</mappers>

pom.xml

<build>
    <resources>
        <resource>
            <directory>src/main/java</directory>
            <includes>
                <include>**/*.xml</include>
                <include>**/*.properties</include>
            </includes>
            <filtering>false</filtering>
        </resource>
        <resource>
            <directory>src/main/resources</directory>
            <includes>
                <include>**/*.xml</include>
                <include>**/*.properties</include>
            </includes>
            <filtering>false</filtering>
        </resource>
    </resources>
</build>