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From MSB <markbrd...@tiscali.co.uk>
Subject Re: I have problem using XSSF
Date Wed, 16 Jun 2010 17:53:06 GMT

The eventmodel is much less memory intensive as it operates at a far 'lower'
level - the usermodel can be thgought of as another layer which makes it
easier to manipulate the workbook but it does require more memory. The
memory requirements of XSSF are higher than those of HWPF as it, XSSF, is
built on top of another library that actually parses the raw XML. Recently,
one of the list members - Bruce - has been throughly testing the performance
of the API and noted a number of places where improvements could be made.
Yegor has made a few changes and it coul be worth while downloading the
lattest version of the API to see if any of these wil help you.

I am not sure that the approach demonstrated in Yegor's BigGridDemo example
is the best one for you to adopt if you are having to sum values and
determine where data should be placed in the workbook. However I have to
admit that I am no expert and it might be perfectly possible with this
approach. You may have to wait a while to see if anyone else responds to
your question or even post another question asking speficlayy if anyone has
used the BigGridDemo appraoch to do what you require.

In the meantime, I think that I would look at manipulating the CSV directly
to order and reorder their contents before creating the Excel workbook. Only
you can tell if this is possible but have you thought about editing the CSV
files - maybe creating one larger file - before attempting to build the


Mark B

imsaikat50 wrote:
> I am using usermodel. can u tell me what can i achieve if i use
> eventusermodel classes. i have taken a look to BigGridDemo.java its
> editing the xml file. it need to tell you that i need to check the 1st
> column of the xlsx file for each 16 csv file and put the data from csv
> file in the corresponding date's cell; if the data already exist in the
> xlsx file then i have to sum the corresponding values of xlsx and csv and
> put it in the xlsx's dated cell.
> thanks. i'll appreciate any other solution/help.
> saikat
> Bangladesh
> MSB wrote:
>> Are you using the usermodel or the eventusermodel classes? I suspect the
>> former if you are having such problems and would suggest that you take a
>> look at Yegor's BigGridDemo.java demonstration code. You should not
>> consider this to be a solution but rather a demonstration of a different
>> approach to creating Excel workbooks.
>> Yours
>> Mark B
>> imsaikat50 wrote:
>>> Dear All,
>>> I write a program on making excel file which reads 16 .csv file one
>>> after another and write the data on it to the excel file. At first the
>>> excel file was of .xls format (Excel 2003). As my row number goes
>>> beyond 65535 i converted the program for handling the .xlsx format
>>> (excel 2007). now the problem is its taking too much time to read from
>>> .csv file and write data to .xlsx than for .xls. i cannot understand
>>> what is happening.
>>> my program is to open one .csv file and read the data then write it to
>>> a .xlsx file (if for first time then create a new .xlsx). then close
>>> the .xlsx and go to the next .csv file and read the existing .xlsx and
>>> write to it.
>>> the same process took 30 to 50 mins when i created .xls and now its
>>> taking more than a day (!). why?
>>> As per my opinion it is the opening and closing of the .xlsx which is
>>> taking time. if that is the reason how i can optimize this issue?
>>> I'll be glad if any one can help me in this issue.
>>> --
>>> Saikat Sarker
>>> Bangladesh

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