The notion of saving pieces to disk in an intelligent way and then
reassembling the file with block links fixed up has been discussed by
POI Developers over the years. It is a very large project, and it has
always been cheaper to recommend more memory.
If someone has plenty of time and the inclination to attempt this then
I am sure that developers here would provide help in how to do it and
still fit into HSSF. Join the dev list, download the code and start
asking questions.
Regards,
Dave
On Jan 26, 2010, at 9:07 AM, MSB wrote:
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
亮 严 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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