当我们使用Kettle在配置好Mysql的连接串内容后,点击【测试】按钮时报错【错误连接数据库 [XXX : 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 (