>________________________________ > From: Enrique <[email protected]> >To: [email protected] >Sent: Wednesday, March 12, 2014 2:23 PM >Subject: Re: XSSF - detecting end of file when reading XLSX files > > >Darren Roberts <robertsdjguard-poi <at> yahoo.com> writes: > >> >> When you deleted the data from row 21 onwards did you just highlight the >cells/data and press delete, or >> select all the row numbers from 21 to the end, right click and select >delete? There is a difference, the >> former just clears the data from the cells but otherwise Excel considers >the cells to have content >> (retains styles etc). If you do the latter it actually deletes the rows >entirely from its internal >> representation. >> >> Have you opened up the xlsx file as a zip and had a look at the XML file >for the sheet? Since you're still seeing >> SAX processing those rows it's my guess that when you saved the file Excel >thought they were still valid >> content cells and wrote out empty cells for all of them. Try deleting the >rows using the method I described, >> and then seeing if SAX still processes them. >> >> >________________________________ >> > From: Enrique <enrique.rochina <at> gmail.com> >> >To: user <at> poi.apache.org >> >Sent: Monday, March 10, 2014 10:48 AM >> >Subject: XSSF - detecting end of file when reading XLSX files >> > >> > >> >Hello, >> > >> >I'm working on making extraction of some excel files (very large files), >> >using XSSF + SAX. >> > >> >I've used some tests files, specifically one that contained thousands of >rows >> >of data. I only wanted to keep few of them, so I deleted all the content >from >> >the 20th row. When I process this excel file, I see that since the 21th >row, >> >every row I processed, with empty results obviously. >> > >> >I would rather expect to have this process finished. Is there anyway to >say >> >to the XSSF processor not to enter this empty rows? >> > >> >I suppose there is a relation with the fact that the file contained more >data >> >in this rows before, but this is a real case that our end users could do. >> > >> >Thanks for your help. >> > >> >Kind regards, >> >Enrique >> > >> > >> >--------------------------------------------------------------------- >> >To unsubscribe, e-mail: user-unsubscribe <at> poi.apache.org >> >For additional commands, e-mail: user-help <at> poi.apache.org >> > >> > >> > >> > > > >Hello Darren, > >I've tested what you said, and that's right. My previous test was based on a >file I deleted the cells with the Delete key. After deleting the content >property, it is not processed by SAX. Moreover, if I've verified that the >content in the zip file has decreased (file \xl\worksheets\sheet3.xml, many >less row elements) > >Now I have a second question that it may relate to SAX: is it possible to >abort or terminate the processing promptly? I have a business case where I >only need to extract the content on the 10 first rows, thus I don't need to >spend time on processing the whole file. > >I've verified, with XSSF + Usermodel it takes too long and too much memory, >only for opening the file. So, XSSF is still a better option > >Thanks > > > >Darren Roberts <robertsdjguard-poi <at> yahoo.com> writes: > > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [email protected] >For additional commands, e-mail: [email protected] >
Yes you can do that, I do it myself by in my SAX processors overidden DefaultHandler.startElement method, simply detect the row element, parse the attribute to get the row number (or increment an internal counter if you prefer) and then do a check to see whether you've reached or passed the row you wish to stop on. In my case at this point I throw a custom exception (SAXRowReachedException) which I explicitly handle in the calling code. I know that using exceptions for flow control is bad form, but I feel it is technically ok as by that point I should have found the required headers and if I've not then that's an exceptional event. Even IBM use the same method here: http://www.ibm.com/developerworks/library/x-tipsaxstop/ Refer to their code if my description isn't clear. --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
