apache poi excel big auto column width

Question

I am try to create a big excel 2010 with 30 columns and 1 million records with Apache poi latest. I am creating as describe in this link http://svn.apache.org/repos/asf/poi

Answer 1

First Select the first row or header because only Header can give you the max number of cells in a row.

HSSFRow row = wb.getSheetAt(0).getRow(0);

Then use autoSizeColumn on each column of that row

for(int colNum = 0; colNum<row.getLastCellNum();colNum++)   
    wb.getSheetAt(0).autoSizeColumn(colNum);

This will set the column width same as that of its Header width.

Answer 2

sheet.autoSizeColumn(columnNumber) works. this will resize the column to the largest cell length.

Answer 3

I would also suggest you look at using sxssf. It uses an xml format to load it into Excel. This is much faster and a better way to create large reports or grids. The autosizing function in xssf takes too long by default.