Excel 中的 DDE 信息 [英] DDE information in Excel

问题描述

    我编写了一个程序来使用 Apache POI 读取 excel 文件，该程序按预期工作.下一部分是实现-拒绝读取包含DDE链接/信息的excel文件.

我通过以下链接阅读了有关 DDE 的信息

• https://en.wikipedia.org/wiki/Dynamic_Data_Exchange
• http://jdde.pretty-tools.com/

• https://v8doc.sas.com/sashtml/win/z3ples.htm

  我无法获得有关如何

的信息

• 一个带有 DDE 信息的 excel 文件.

• 识别包含DDE信息的excel文件

  如果有人能帮助我理解以上两点就好了.

    提前致谢

解决方案

对于 XSSF 可以得到 ExternalLinksTables 来自 XSSFWorkbook 使用 XSSFWorkbook.getExternalLinksTable.

然后遍历那个List，得到CTExternalLink 使用 ExternalLinksTable.getCTExternalLink 然后检查是否CTExternalLink.isSetDdeLink 为 true.如果是这样，我们在那里有一个 DDE 链接.

外部链接，如 ='C:\Users\Paul\Documents\[2014 Budget.xlsx]Details'!$R$7 或 ='http://teamsite.company.com/corporate/[MySpreadsheet.xlsx]‌ Sheet1'!F4 与 DDE 无关.使用此类链接没有危险，因此没有理由拒绝读取包含"此类链接的 excel 文件.DDE 链接在 Excel 中看起来像 =ddeapp|'parameters'!reference.因此，我们需要将 DDE 链接与其他链接不同，并且仅拒绝读取 excel 文件，如果它包含"真的 DDE 链接.使用 CTExternalLink.isSetDdeLink 我们能够做到这一点.

我怀疑拒绝读取包含 DDE 链接的 excel 文件"的要求是关于避免在 Excel 中使用像 =ddeapp|'parameters'!reference 这样的单元格公式.如果用户不专心并且是管理员，则使用这样的公式可能会做非常糟糕和危险的事情.示例:=cmd|'/C control'!anyname.这将在 Windows 中打开系统控制应用程序，如果用户是管理员，那么它将允许更多...

由于 DDE 是来自 IT 新石器时代的古老技术，目前还没有很好的例子可以有效地使用 DDE.您需要一个 ddeapp，它是一个允许通过 DDE 联系并返回一个值的应用程序.此 youtube 视频:DTN IQFeed 的 DDE 链接设置展示了一个示例.>

     I wrote a program to read excel files using Apache POI which is working as expected. Next part is to implement - "To reject reading excel file if it contains DDE links/information.

I read about DDE information via below links

• https://en.wikipedia.org/wiki/Dynamic_Data_Exchange
• http://jdde.pretty-tools.com/

• https://v8doc.sas.com/sashtml/win/z3ples.htm

  I could not get information on how

• an excel file looks like with DDE information.

• to identify an excel file that contains DDE information

  It would be great if someone can help me in understanding the above two points.

     Thanks in Advance

解决方案

For XSSF one could get the List of ExternalLinksTables from the XSSFWorkbook using XSSFWorkbook.getExternalLinksTable.

Then iterate through that List, get CTExternalLink for each ExternalLinksTable using ExternalLinksTable.getCTExternalLink and then check whether CTExternalLink.isSetDdeLink is true. If so, we have a DDE link there.

External links like ='C:\Users\Paul\Documents\[2014 Budget.xlsx]Details'!$R$7 or ='http://teamsite.company.com/corporate/[MySpreadsheet.xlsx]‌​Sheet1'!F4 have nothing to do with DDE. There is no danger while using such links and so no reason to "reject reading excel file if it contains" such links. A DDE link looks like =ddeapp|'parameters'!reference in Excel. So we need to differ DDE links from others and only "reject reading excel file if it contains" really DDE links. Using CTExternalLink.isSetDdeLink we are able to do this differentation.

I suspect the requirement "reject reading excel file if it contains DDE links" is about avoiding cell formulas like =ddeapp|'parameters'!reference in Excel. Using such formulas one could do really bad and dangerous things if the user is not attentively and is administrator. Example: =cmd|'/C control'!anyname. This will open system control application in Windows and if the user is administrator, then it would allow much more...

Since DDE is ancient technology from neolithic of IT, there are currently no good examples for using DDE in a productive way. You need a ddeapp which is a application which allows contact via DDE and returns a value then. This youtube video: DDE Link Setup for DTN IQFeed shows an example.

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