一、beans.xml

<beans ....

           xmlns:p="http://www.springframework.org/schema/p"
..>

<bean id="dataSource"    class="org.apache.commons.dbcp.BasicDataSource"
      destroy-method="close"
      p:driverClassName="com.mysql.jdbc.Driver"
      p:url="jdbc:mysql://localhost:3306/spring"
      p:username="root"
      p:password="root"/>

二、beans.xml

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

  <property name="locations" value="classpath:jdbc.properties"/>
	</bean>

	<bean id="dataSource" destroy-method="close"
    class="org.apache.commons.dbcp.BasicDataSource">
  <property name="driverClassName" value="${jdbc.driverClassName}"/>
  <property name="url" value="${jdbc.url}"/>
  <property name="username" value="${jdbc.username}"/>
  <property name="password" value="${jdbc.password}"/>
</bean>

? jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring
jdbc.username=root
jdbc.password=root