https://blog.csdn.net/gikieng/article/details/47150567 https://blog.alswl.com/2018/03/sql-server-migration-1/ https://www.xuebuyuan.com/zh-hant/1922708.html
log4j:Error could not instantiate appender named "DB"
https://bbs.csdn.net/topics/390465887?page=1
找不到类???