Spring框架中的PropertyPlaceholderConfigurer类
Spring框架中的PropertyPlaceholderConfigurer类

PropertyPlaceholderConfigurer类可以在applicationContext.xml配置文件中加入一个或者多个外部属性文件properties(注意location和locations属性)：

<!-- 一个外部文件 -->
<bean id="propertyConfigurer" value="classpath:/conf/jdbc-mysql.properties"/>
</bean>

<!-- 多个外部文件 -->
<bean id="propertyConfigurer" destroy-method="close">
<property name="driverClass" value="${c3p0.driverClassName}" />
<property name="jdbcUrl" value="${c3p0.jdbcUrl}" />
<property name="user" value="${c3p0.user}" />
<property name="password" value="${c3p0.password}" />
<property name="maxPoolSize" value="${c3p0.maxPoolSize}" />
<property name="minPoolSize" value="${c3p0.minPoolSize}" />
<property name="initialPoolSize" value="${c3p0.initialPoolSize}" />
<property name="breakAfterAcquireFailure" value="${c3p0.breakAfterAcquireFailure}" />
</bean>