启动SSM项目报错，请问怎么解决，谢谢！ <b> ?报错

报错如下：
Invalid bean definition with name 'dataSource' defined in file [E:\boke\01 one day\eclipse\eclipse-mars\work\taotao-manager\taotao-manager-web\target\classes\spring\applicationContext-dao.xml]: Could not resolve placeholder 'jdbc.url' in string value "${jdbc.url}"; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'jdbc.url' in string value "${jdbc.url}"

    <context:property-placeholder location="classpath:properties/*.properties" />
<!-- 数据库连接池 -->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
    destroy-method="close">
    <property name="url" value="${jdbc.url}" />
    <property name="username" value="${jdbc.username}" />
    <property name="password" value="${jdbc.password}" />
    <property name="driverClassName" value="${jdbc.driver}" />
    <property name="maxActive" value="10" />
    <property name="minIdle" value="5" />
</bean>

JDBC:
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/taotao
jdbc.username=root
jdbc.password=root