我按照老师的步骤一步一步来实现在运行测试的时候出现以下问题：

1、Caused by: java.io.FileNotFoundException: http://www.mybatis.org/dtd/mbatis-3-config.dtd

2、Caused by: org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: java.io.FileNotFoundException: http://www.mybatis.org/dtd/mbatis-3-config.dtd

3、Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/imooc/demo/config/dao/SessionFactoryConfiguration.class]: Invocation of init method failed; nested exception is org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: java.io.FileNotFoundException: http://www.mybatis.org/dtd/mbatis-3-config.dtd

4、Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'areaDao' defined in file [E:\ideaworkplace\demo\target\classes\com\imooc\demo\dao\AreaDao.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [com/imooc/demo/config/dao/SessionFactoryConfiguration.class]: Invocation of init method failed; nested exception is org.apache.ibatis.builder.BuilderException: Error creating document instance.  Cause: java.io.FileNotFoundException: http://www.mybatis.org/dtd/mbatis-3-config.dtd