typeAliasesPackage 属性的作用

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
                http://www.springframework.org/schema/beans/spring-beans.xsd
                http://www.springframework.org/schema/context
                http://www.springframework.org/schema/context/spring-context.xsd
                http://www.springframework.org/schema/aop
                http://www.springframework.org/schema/aop/spring-aop.xsd
                http://www.springframework.org/schema/tx
                http://www.springframework.org/schema/tx/spring-tx.xsd
                http://www.springframework.org/schema/mvc
                http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--dao层配置文件开始-->
    <!--配置连接池-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql:///maven"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <!--配置生产SqlSession对象的工厂-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <!--扫描pojo包，给包下所有pojo对象起别名-->
        <property name="typeAliasesPackage" value="com.itheima.domain"/>
    </bean>

    <!--扫描接口包路径，生成包下所有接口的代理对象，并且放入spring容器中-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.itheima.dao"/>
    </bean>
    <!--dao层配置文件结束-->

    <!--service层配置文件开始-->

    <!--组件扫描配置-->
    <context:component-scan base-package="com.itheima.service"/>

    <!--aop面向切面编程，切面就是切入点和通知的组合-->
    <!--配置事务管理器-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!--配置事务的通知-->
    <tx:advice id="advice">
        <tx:attributes>
            <tx:method name="save*" propagation="REQUIRED"/>
            <tx:method name="update*" propagation="REQUIRED"/>
            <tx:method name="delete*" propagation="REQUIRED"/>
            <tx:method name="find*" read-only="true"/>
            <tx:method name="*" propagation="REQUIRED"/>
        </tx:attributes>
    </tx:advice>

    <!--配置切面-->
    <aop:config>
        <aop:pointcut id="pointcut" expression="execution(* com.itheima.service.impl.*.*(..))"/>
        <aop:advisor advice-ref="advice" pointcut-ref="pointcut"/>
    </aop:config>
    <!--service层配置文件结束-->

</beans>

ItemsDao.xml(Maper):

<?xml version="1.0" encoding="UTF-8" ?>
        <!DOCTYPE mapper
                PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
                "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.dao.ItemsDao">
    <select id="findById" parameterType="int" resultType="items">
        select * from items where id = #{id}
    </select>
</mapper>

如上例子，如果 typeAliasesPackage不进行配置，resultType就得写全名resultType="com.itheima.domain.items"，但是如果配置了别名<property name="typeAliasesPackage" value="com.itheima.domain"/>，就可以不用写全路径直接写resultType="items"即可，具体如下显示：

<mapper namespace="com.itheima.dao.ItemsDao">
    <select id="findById" parameterType="int" resultType="items">
        select * from items where id = #{id}
    </select>
</mapper>