Error analysis: due to each Mapper.xml You need to register in the mybatis core configuration file

Solution: in mybatis- config.xml Add the following lines of code to the configuration file (note that the path must be filled in correctly, according to COM/LyP/Dao)/ UserMapper.xml (fill in the form of)

 <mappers>
        <mapper resource="com/lyp/dao/UserMapper.xml"/>
 </mappers>