Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!

做Spring+Mybatis的專案，報錯

jdbc.properies:

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

   <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="${driver}"/>
        <property name="jdbcUrl" value="${url}"/>
        <property name="user" value="${username}"/>
        <property name="password" value="${password}"/>
 

最後發現是username的問題，好像改個名就可以，比如：usernamex=root

 <property name="user" value="${usernamex}"/>