如何使用Spring配置基于属性文件配置一个实现？

database.url=jdbc:mysql://localhost:3306/mydb
database.username=root
database.password=123456
server.port=8080

<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"
       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">

    <!-- 加载属性文件 -->
    <context:property-placeholder location="classpath:config.properties"/>

    <!-- 定义Bean -->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="url" value="${database.url}"/>
        <property name="username" value="${database.username}"/>
        <property name="password" value="${database.password}"/>
    </bean>

    <bean id="server" class="com.example.Server">
        <property name="port" value="${server.port}"/>
    </bean>

</beans>