----------------------------------------------------------------------------------------------------------------------------------通過Properties的方式配置xml的datasource：

1、 編寫properties檔案：

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

<!-- placeholder 佔位符 -->
	<bean
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="locations">
			<value>classpath:jdbc.properties</value>
		</property>
	</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>