使用mysql8.+版本，使用mybatis的代码生成工具：mybatis-generator连接数据库时Unknown initial character set index '255' received from server. Initial client character set can be forced via the 'characterEncoding' property.

Error connecting to database: (using class org.gjt.mm.mysql.Driver)
Unknown initial character set index ‘255’ received from server. Initial client c
haracter set can be forced via the ‘characterEncoding’ property.
问题分析：
如果etl调度服务lib下存在多个版本的mysql驱动，则提示上述问题：
mysql-connector-java-3.1.14-bin.jar
mysql-connector-java-5.1.47.jar
解决办法：
删除低版本驱动文件。

是因为使用的mysql-connector-java版本太低了，更换成最新版本