获取SqlSession的分析:
InputStream inputStream = Resources.getResourceStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder.build(inputStream);
SqlSession sqlSession= sqlSessionFactory.openSession();
为什么说第一段代码读取了mybatis-config.xml和Mapper.xml
因为在mybatis-config.xml中有的标签