Kettle 添加Mysql驱动后仍提示连接错误

错误连接数据库 [kettle_mysql] : org.pentaho.di.core.exception.KettleDatabaseException: 
Error occurred while trying to connect to the database Driver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed. org.gjt.mm.mysql.Driver 
org.pentaho.di.core.exception.KettleDatabaseException: 
Error occurred while trying to connect to the database Driver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed. org.gjt.mm.mysql.Driver

有可能是使用的mysql驱动jar包不包含‘org.gjt.mm.mysql‘ 这个Driver class文件；也有可能是缺少驱动；

可以查看jar包下是否包含有org.gjt.mm.mysql的 Driver.class文件，没有这个文件则需要更换驱动；

实际情况是本人通过kettle9.1版本通过mysql8.0的驱动连接5.7的mysql是能成功连接的，但是对应8.0的mysql驱动复制到老版本8.0的kettle就出现如上问题，最后是在老版本的kettle里使用了mysql5.1.47的驱动可以正常使用。