Invalid property 'driver' of bean class [org.apache.commons.dbcp.BasicDataSource]

Spring整合MyBatis！

main方法测试，出现异常：

一堆错，很懵逼！

别慌，慢慢分析，也许错误很简单；

先分析一下applicationContext.xml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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="config" class="org.springframework.beans.factory.config.PreferencesPlaceholderConfigurer">
		<property name="locations">
			<array>
				<value>classpath:db.properties</value>
			</array>
		</property>
	</bean>

	 <bean id="studentService" class="com.guor.service.impl.StudentServiceImpl">
		<property name="studentMapper" ref="studentMapper"></property>
	</bean>
	
	<bean id="studentMapper" class="com.guor.dao.impl.StudentDaoImpl">
	    <!--  将spring配置的 sqlSessionFactory 交给mapper(dao层) -->
		<property name="sqlSessionFactory" ref="sqlSessionFactory"></property> 
	</bean> 

	<!-- 配置数据库信息（替代mybatis的配置文件confx.ml）   -->
	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
		<property name="driver" value="${driver}"></property>
		<property name="url" value="${url}"></property>
		<property name="username" value="${username}"></property>
		<property name="password" value="${password}"></property>
	</bean> 
	
	 <!-- 在springIOC中创建mybatis的核心类SqlSessionFactoryBean  -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="dataSource"></property>
		<property name="mapperLocations" value="com/guor/mapper/*.xml"></property>
	</bean> 
</beans>

分析思路：

1、全部注掉；

2、放开对外层的那一部分；

dataSource

dataSource是org.apache.commons.dbcp.BasicDataSource中的