com.mysql.jdbc.Driver ==》 com.mysql.cj.jdbc.Driver
错误信息：
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@16676fb7] was not registered for synchronization because synchronization is not active Loading class `com.mysql.jdbc.Driver'.
This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
解决方案：
com.mysql.jdbc.Driver ==》 com.mysql.cj.jdbc.Driver
原因：
mysql 的驱动类，位置改变了