spring加载配置文件

jdbc.url=jdbc:mysql://localhost:3306/setcharcter?characterEncoding=utf8&serverTimezone=UTC
jdbc.password=123456
jdbc.username=root
jdbc.driver=com.mysql.jdbc.Driver

<?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"
    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 " default-autowire="byName" >
       <context:property-placeholder location="classpath:db.properties"/>
        <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
                <property name="driverClassName" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="password" value="${jdbc.password}"></property>
                <property name="username" value="${jdbc.username}"></property>
        </bean>
        <bean id="factory" class="org.mybatis.spring.SqlSessionFactoryBean">
                    <property name="dataSource" ref="dataSource"></property>
         </bean>
         <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
                     <property name="basePackage" value="com.mapper"></property>
                     <!-- 当使用自动注入的时候　优先级比较高
　　　　　　　　　　　　　　会先创建对象,在加载配置文件,这样的话配置文件的信息就取不到了　
　　　　　　　　　　　　　　所以要使用这个,不然会加载不到properties文件的属性值 -->
                     <property name="sqlSessionFactoryBeanName" value="factory"></property>
         </bean>
</beans>