使用Java执行kettle脚本报错：
错误连接数据库 [mysql_rollback] : 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
确保Java环境中的mysql数据库驱动存在，kettle中的mysql 数据库类型使用MySQL5之前的驱动，现在已经完全没有人用了，使用最新的kettle8 在最新驱动放在lib文件夹下进行链接测试仍然会出现错误（一直去找org.gjt.mm.mysql.Driver驱动类，原因不明，有时间看一下源码）。
使用MySQL数据库可以绕过这个问题：选择Generic database
