在第一次测试代码的spring.xml文件
<!--4.连接数据库-->
<bean id="db" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/chaoshi"></property>
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="user" value="root"></property>
<property name="password" value="123456"></property>
</bean>
<bean id="fac" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="db"></property>
<property name="mapperLocations" value="classpath:/mapper/*.xml"></property>
</bean>
<bean id="temp" class="org.mybatis.spring.SqlSessionTemplate">
<!--构造方法参数没有,index=0-->
<constructor-arg index="0" ref="fac"></constructor-arg>
</bean>
改为
<!--连接数据库-->
<context:property-placeholder location="classpath:db.properties"></context:property-placeholder>
<bean id="db" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/mydbb"></property>
<property name="user" value="root"></property>
<property name="password" value="123456"></property>
</bean>
<bean id="fac" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="db"></property>
<property name="mapperLocations" value="classpath:/mapper/*.xml"></property>
<property name="configLocation" value="classpath:mybatis.xml"></property>
</bean>
<!--注释掉之前的代码-->
<!-- <bean id="temp" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg index="0" ref="fac"></constructor-arg>
</bean>-->
<!--省略dao实现类-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.ly.dao"></property>
<property name="sqlSessionFactory" ref="fac"></property>
</bean>