nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.

nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:
Error querying database. Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. It's likely that neither a Result Type nor a Result Map was specified.
Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. It's likely that neither a Result Type nor a Result Map was specified.

This exception is thrown when there is an issue with executing a query using MyBatis framework. In this case, the nested exception is org.apache.ibatis.exceptions.PersistenceException, which indicates that there was an error querying the database.

The specific error message states that no Result Maps were found for the Mapped Statement 'com.example.mapper.UserMapper.getUserById'. This means that either a Result Type or a Result Map was not specified for the query.

To resolve this issue, you need to make sure that the appropriate Result Type or Result Map is specified for the query in the MyBatis mapping file (XML) or in the annotation-based configuration.