下面是报错信息，
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.teachers.test.mapperTest': Unsatisfied dependency expressed through field 'video'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.teachers.dao.VideoMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1264)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:386)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:118)
at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:230)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:228)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:287)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:289)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:247)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at org.junit.vintage.engine.execution.RunnerExecutor.execute(RunnerExecutor.java:42)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(Unknown Source)
at java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
at java.util.Iterator.forEachRemaining(Unknown Source)
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Unknown Source)
at java.util.stream.AbstractPipeline.copyInto(Unknown Source)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(Unknown Source)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(Unknown Source)
at java.util.stream.AbstractPipeline.evaluate(Unknown Source)
at java.util.stream.ReferencePipeline.forEach(Unknown Source)
at org.junit.vintage.engine.VintageTestEngine.executeAllChildren(VintageTestEngine.java:83)
at org.junit.vintage.engine.VintageTestEngine.execute(VintageTestEngine.java:74)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:170)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:154)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:90)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:86)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.teachers.dao.VideoMapper' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1486)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1104)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585)
... 46 more
之前的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"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
<!-- Spring的配置文件，这里主要配置和业务逻辑有关的 -->
<!-- 数据源，事物控制...... -->
<context:component-scan base-package="com.teachers.*">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
</context:component-scan>
<context:property-placeholder location="classpath:dbConfig.properties"/>
<bean id = "pooledDataSource" class = "com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="jdbcUrl" value = "${jdbc.jdbcUrl}"></property>
<property name="driverClass" value = "${jdbc.driverClass}"></property>
<property name="user" value = "${jdbc.user}"></property>
<property name="password" value = "${jdbc.password}"></property>
</bean>
<!-- ============================================================================================== -->
<!-- 配置和myBatis的整合 -->
<bean id= "sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<!-- 指定myBatis全局配置文件的位置 -->
<property name="configLocation" value = "classpath:mybatis-config.xml"></property>
<property name="dataSource" ref = "pooledDataSource"></property>
<!-- 指定myBatis mapper文件的位置 -->
<property name="mapperLocations" value = "classpath:com.teachers.mappers.*"></property>
</bean>
<!-- 配置扫描器，将myBatis接口的实现加入到IOC容器中 -->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<!-- 扫描所有的Dao接口的实现，加入到IOC容器中 -->
<property name="basePackage" value = "classpath:com.teachers.dao"></property>
</bean>
<!-- ================================================================================================== -->
<!-- 事物控制的配置 -->
<bean id = "transactionManager" class ="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<!-- 控制住数据源 -->
<property name="dataSource" ref="pooledDataSource"></property>
</bean>
<!-- 开启基于注解的事务，使用xml配置形式的事务（必要主要的都是配置式） -->
<aop:config>
<!-- 切入点表达式 -->
<aop:pointcut expression="execution(* com.teachers.service..*(..))" id="txPoint"/>
<!-- 配置事务增强 -->
<aop:advisor advice-ref="txAdvice" pointcut-ref="txPoint"/>
</aop:config>
<!-- 配置事务增强，事务如何切入 -->
<tx:advice id = "txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<!-- 所有方法都是事务方法 -->
<tx:method name="*"/>
<!-- 以get开始的所有方法 -->
<tx:method name="get*" read-only="true"/>
</tx:attributes>
</tx:advice>
<!-- spring配置文件的核心关注点
1.数据源
2.与myBatis的整合
3.事务控制
-->
</beans>
错误原因：在配置dao路径的时候加了classpath，去掉之后测试通过。
这个问题我竟然搞了整整一天，最后在csdn上面发帖求助才解决，需要加强学习。
感谢 https://my.csdn.net/qq_39537939 的帮助。