Could not load driverClass ${jdbc.driver}-向日葵屋

Could not load driverClass ${jdbc.driver}

蔚落 2022-05-25 08:53 232阅读 0赞

今天在整合ssm做spring-mvc的Junit测试时，出现这样的错误如下：

Could not load driverClass ${jdbc.driver}
java.lang.ClassNotFoundException: ${jdbc.driver}
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at com.mchange.v2.c3p0.DriverManagerDataSource.ensureDriverLoaded(DriverManagerDataSource.java:100)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:132)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
    at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)

spring-dao.xml配置如下：

<!-- 配置整合mybatis过程 -->
    <!-- 1.配置数据库相关参数的properties的属性 -->
     <context:property-placeholder location="classpath:jdbc.properties"/>
     <!-- 配置数据库连接池 -->
     <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置连接池属性 -->
        <property name="driverClass" value="${jdbc.driver}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />
        <!-- c3p0连接池的私有属性 -->
        <property name="maxPoolSize" value="30" />
        <property name="minPoolSize" value="10" />
        <!-- 关闭连接后不自动commit -->
        <property name="autoCommitOnClose" value="false" />
        <!-- 获取连接超时时间 -->
        <property name="checkoutTimeout" value="10000" />
        <!-- 当获取连接失败重试次数 -->
        <property name="acquireRetryAttempts" value="2" />
    </bean>
     <!-- 3.配置SqlSessionFactory -->
     <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
         <!-- 注入数据库连接池 -->
         <property name="dataSource" ref="dataSource"/>
         <!-- 配置mybatis全局配置文件：mybatis-config.xml -->
         <property name="configLocation" value="classpath:mybatis-config.xml"></property>
         <!-- 扫描entity -->
         <property name="typeAliasesPackage" value="com.itwx.o2o.entity"></property>
         <!-- 扫描SQL配置文件mapper需要的xml文件 -->
         <property name="mapperLocations" value="classpath:mapper/*.xml"></property>
     </bean>
     <!-- 4.配置扫描Dao接口包，动态实现Dao接口，注入到Spring容器中 -->
     <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
         <!-- 注入sqlSessionFactoy -->
         <property name="sqlSessionFactory" ref="sqlSessionFactory" />
         <!-- 扫描的dao层接口包 -->
         <property name="basePackage" value="com.itwx.o2o.dao"></property>
     </bean>
 </beans>

重点错误是在配置扫描接口的时候出现错误，加红处配置错误；

如果将 ${jdbc.driverClassName} 改成具体的值就不会报错！
解决方案一：
将
　　<property name="sqlSessionFactory" ref="sqlSessionFactory"/>
改成
　　<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
记住ref要改成value 
原因分析：是因为配置了class="org.mybatis.spring.mapper.MapperScannerConfigurer"，而这句代码会在数据源加载前就执行了，之后就把表达式${jdbc.driverClassName}当成字符串执行了。