空值写入oracle数据库date类型报错

从一个ftp取文件写入oracle数据库时，有一个日期类型的字段有空值，写入时报 ERROR StdoutPluginCollector - 脏数据:
{"exception":"TIMESTAMP 类型转换错误，请帮忙看看怎么解决，谢谢！

Start by reproducing the FTP-to-Oracle import with an empty date field and trace the reported "TIMESTAMP type conversion error" through the Oracle writer and date-conversion entry points. Done means a null date is handled without producing dirty data, with the relevant behavior covered by a regression test if the project has one.

Written by the indexing model from the issue text.