Cause: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)

问题：

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
### The error may exist in com/sise/mybatis/mapper/UserMapper.xml
### The error may involve com.sise.mybatis.mapper.UserMapper.selectAllUser
### The error occurred while executing a query
### Cause: java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
Process finished with exit code 0

被这个问题搞了好久：
让我一直怀疑是我代码逻辑问题或者环境问题，但找了很久很久，发现

少了一个大括号}
抓狂…

之前就出现过这种问题，我一直以为是环境问题，以为我百分之百确认我的数据库密码和用户名正确，万万没想到啊…所以遇到这种问题的同学，一定要查找用到密码或用户名的地方，肯定是这些地方出了差错。