mybatis报错：Could not instantiate bean class [Dao.stuDao]: Specified class is an interface

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'stuDao' defined in class path resource [applicationContext.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [Dao.stuDao]: Specified class is an interface
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1011)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:957)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:490)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461)
 at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
 at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
 at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
 at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
 at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607)
 at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
 at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
 at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
 at tests.stuDaoImplTest.setUp(stuDaoImplTest.java:19)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:606)
 at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
 at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
 at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
 at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:27)
 at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:69)
 at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:48)
 at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
 at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
 at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
 at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
 at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
 at org.junit.runners.ParentRunner.run(ParentRunner.java:292)
 at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
 at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
 at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [Dao.stuDao]: Specified class is an interface
 at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:67)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1004)
 ... 36 more

本错误的意思为：指定接口不能被实例化

applicationContext.xml中注入dao错误写法：

<!--原始的dao接口  --><bean id="stuDao" class="Dao.stuDao"><property name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>

正确如下：

<!--原始的dao接口  --><bean id="stuDao" class="Dao.stuDaoImpl"><property name="sqlSessionFactory" ref="sqlSessionFactory"/></bean>