报错说明1：
org.apache.ibatis.binding.BindingException: Type interface com.jt.mapper.DemoUserMapper is not kNown to the MapperRegistry.
解决方案：检查.xml映射文件中namespace的值，是否与mapper层中的接口一致
报错说明2：
org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.jt.mapper.DemoUserMapper.findAll
解决方案：检查.xml映射文件中id的值，是否与mapper层中的接口的方法名一致
报错说明3：
org.apache.ibatis.exceptions.PersistenceException:
### Error building sqlSession.
### The error may exist in mybatis\mappers\DemoUserMapper.xml
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing sql Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. The XML location is 'mybatis\mappers\DemoUserMapper.xml'. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'com.jt.pojo.DemoUserp'. Cause: java.lang.classNotFoundException: Cannot find class: com.jt.pojo.DemoUserp
解决方案：检查.xml映射文件中resultType的值，是否与实体对象路径一致
报错说明4:
org.apache.ibatis.exceptions.PersistenceException:
### Error building sqlSession.
### The error may exist in mybatis\mappers\DemoUserMapperh.xml
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing sql Mapper Configuration. Cause: java.io.IOException: Could not find resource mybatis\mappers\DemoUserMapperh.xml
解决方案：检查mybatis核心配置文件中加载映射文件的路径是否正确
