xlsx4j - How to set column width in spreadsheet?

Question

I'm trying to export JTable to XLSX file using xlsx4j, but have trouble with setting the columns widths. I've succeeded in setting the default width for all the columns, but I would like to set the widths of columns to fit data lenght automatically:

public void exportToXLS() throws Exception
{           
    //Create the spreadsheet
    SpreadsheetMLPackage pkg = SpreadsheetMLPackage.createPackage();
    WorksheetPart sheet = pkg.createWorksheetPart(new PartName("/xl/worksheets/sheet1.xml"), "Sheet1", 1);

    //Set default format for rows and columns
    CTSheetFormatPr format = Context.getsmlObjectFactory().createCTSheetFormatPr();
    format.setDefaultColWidth(20.0);        
    format.setDefaultRowHeight(16.8);
    format.setCustomHeight(Boolean.TRUE);
    sheet.getJaxbElement().setSheetFormatPr(format);

    //Get a few JTable properties 
    int iSelectedTab = tabPane.getSelectedIndex();
    int[] rowsSelected = table[iSelectedTab].getSelectedRows();
    int iColumns = table[0].getColumnCount();
    int iCurrentRow;

    //Retrieve SheetData from sheet object
    SheetData sheetData = sheet.getJaxbElement().getSheetData();
    Row row;
    Cell cell;

    //Copy data from JTable to spreadsheet  
    for(int iRow=0; iRow < rowsSelected.length; iRow++)
    {                       
        iCurrentRow = rowsSelected[iRow];
        row = Context.getsmlObjectFactory().createRow();
        List<Cell>rowl = row.getC();
        for(int iCol = 0; iCol < iColumns; iCol++)
        {
            cell = Context.getsmlObjectFactory().createCell();              
            CTRst ctrst = new CTRst();
            ctrst.setT(table[iSelectedTab].getValueAt(iCurrentRow, iCol).toString());
            cell.setT(STCellType.INLINE_STR);
            cell.setIs(ctrst);              
            rowl.add(cell);

        }
        sheetData.getRow().add(row);            
    }

    //Set the columns widths
    List<Cols> lstCols = sheet.getJaxbElement().getCols();
    System.out.println("lstCols.size() is " + lstCols.size());
    for(int i = 0; i< lstCols.size(); i++)
    {
        List<Col> lstCol = lstCols.get(i).getCol();
        System.out.println("lstCol.size() is " + lstCol.size());
        for(int j=0; j<lstCol.size(); j++)
        {               
            lstCol.get(j).setBestFit(Boolean.TRUE);
            lstCol.get(j).setWidth(30.0);   
            System.out.println("Column " + i + " : " + j);
        }
    }

    //Save the spreadsheet to file
    pkg.save(new File("Export.xlsx"));              
}

The above code shows in console: lstCols.size() is 0 so it looks like after adding rows and cells to the SheetData, there are no columns definitions.

On the other hand if I create the columns manually this way:

Cols cols = Context.smlObjectFactory.createCols();  
Col col = Context.smlObjectFactory.createCol();
col.setBestFit(Boolean.TRUE);
cols.getCol().add(col);
sheet.getJaxbElement().getCols().add(cols);

I get the catastrophic error in XLSX file.

Answer 1

From the ECMA-376 spec (I looked at 3ed, section 18.3.1.17, p1774):

This example shows that column 4 (D) has 'best fit' applied to it, which is also a custom width. Also, column 5 (E) is listed as having a custom width and a style applied at the column level (as opposed to the cell level).

<cols>
<col min="4" max="4" width="12" bestFit="1" customWidth="1"/>
<col min="5" max="5" width="9.140625" style="3"/>
</cols>

so, it looks like you just need to complete your col object definition, by specifying the col number (via min/max attributes).

<col min="2" max="2" bestFit="1"/>

gives a col which starts with zero width, so you should specify @width.

@bestFit doesn't seem to do what you'd expect (you want something more like autoFit?).

See custom-column-widths-in-excel-open-xml and calculating-column-widths-in-excel-open-xml for more.