Spring IOC容器基于配置文件装配Bean(6) ------bean引用外部属性文件

<?xml version="1.0" encoding="UTF-8"?>
<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-4.2.xsd">

    <!--测试bean引用外部属性-->
    <!--<config id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">-->
        <!--<property name="username" value="root"/>-->
        <!--<property name="password" value="123456"/>-->
        <!--<property name="url" value="jdbc:mysql://127.0.0.1:3306/ylws"/>-->
        <!--<property name="driverClassName" value="com.mysql.jdbc.Driver"/>-->
    <!--</config>-->

    <!--引入外部属性文件-->
   <context:property-placeholder location="classpath:config/jdbc.properties"/>

    <!--c3p0-->
    <bean id="dataSourceC3p0" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!--引用properties文件-->
        <property name="user" value="${user}"/>
        <property name="password" value="${password}"/>
        <property name="jdbcUrl" value="${jdbcUrl}"/>
        <property name="driverClass" value="${driverClass}"/>
    </bean>

    <!--通过Properties配置属性-->
    <!--<config id="dataSource" class="com.spring.cn.configig.collections.DataSource">
        <property name="properties">
            <props>
                <prop key="username">root</prop>
                <prop key="password">123456</prop>
                <prop key="url">jdbc:mysql//localhost:3306?</prop>
                <prop key="driver">com.mysql.cj.jdbc.driver</prop>
            </props>
        </property>
    </config>-->
</beans>

jdbc.properties

user=root
password=123456
jdbcUrl=jdbc:mysql://127.0.0.1:3306/ylws
driverClass=com.mysql.jdbc.Driver