xml에서 properties 설정 사용하기

<bean id="propertyPlaceholderConfigurer"

        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

        <property name="locations">

            <value>classpath:/properties/db.properties</value>   

        </property>

    </bean>

상기 등록 후 

<property name="username" value="${username}" />