Thank you Mark B.
I will have a try.
Yan
On 2010年01月27日 15:35, MSB wrote:
Yegor wrote a proof of concept called BigGridDemo
(http://svn.apache.org/repos/asf/poi/trunk/src/examples/src/org/apache/poi/xssf/usermodel/examples/BigGridDemo.java)
that, as far as I understand it, streams the data into a temporary file and
then 'merges' that data into a worksheet. I do not know how far this
technique has been developed yet but there are other list members who have
used the technique to create large worksheet files successfully. It does
however work only for the newer xml based file format introduced in
Office2007.
Yours
Mark B
亮 严 wrote:
Hi guys,
Thanks for your replies. That is great help for me.
Mark B,
XSSF spends more memory than HSSF, in creating a same content excel file.
If there is a better way to handle writing large file using XSSF, I'd like
to have a try.
Would you please to tell me how i can do that using XSSF?
Thanks!
Yan
Date: Tue, 26 Jan 2010 09:07:34 -0800
From: [email protected]
To: [email protected]
Subject: Re: What's the best way to use poi to create large excel files?
I am assuming that you are interested only in creating binary (.xls)
files
and are not targetting the newer xml based ones (.xlsx). If this is the
case
then no, there is not a better way I am sorry to say. The reason lies in
the
file format itself; briefly, the xls file consists of a series of streams
of
data and pointers to various locations in the file, all of it block
structured. It is not possible to determine how the file should be sorted
into blocks nor to calculate the pointers until all of the data for the
file
has been accumulated and so, it is not possible to write .xls files out
to
memory in smaller chunks.
Yours
Mark B
Yan wrote:
Hi guys,
From the docs on the poi web site. I know we can use
org.apache.poi.hssf.usermodel.HSSFWorkbook to create excel 2003 file,
like
HSSFWorkbook workbook = new HSSFWorkbook(); And use
workbook.write("test.xls") to generate the excel file. If you want to
have
a low memory cost only to read excel file, you can use eventmodel.
But if i will create a large excel file, it will cost a lot memory to
get
the whole workbook object ready before writing to file using
workbook.write("***") . What's the best way to use poi to create large
excel files? I donot think it is the best way to set a large heap of
jvm.
Need your help. Thanks!
Your friend
Yan
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