HSSFColor，无背景单元格返回错误的背景色

Question

I am using apache poi 3.9 in my project. I am trying to read HSSF object excel cell and from that I am trying to get the background color

Workbook myWorkBook = WorkbookFactory.create(new File(filePath));
Sheet mySheet = myWorkBook.getSheetAt(0);

Row currentRow = null;
Iterator<Row> rowIterator = mySheet.iterator();
while (rowIterator.hasNext())
{
currentRow = (Row) rowIterator.next();
totalColumns = currentRow.getPhysicalNumberOfCells();

for (int column = 0; column < totalColumns; column++)
{
Cell cell = currentRow.getCell(column);
CellStyle cellStyle = cell.getCellStyle();
short colorIdx=cellStyle.getFillForegroundColor();

HSSFWorkbook workbook = (HSSFWorkbook)myWorkBook;
HSSFPalette palette = workbook.getCustomPalette();
HSSFColor color = palette.getColor(colorIdx);

short[] triplet = color.getTriplet();
System.out.println("Now Color :"+triplet[0]+"-"+triplet[1]+"-"+triplet[2]);
}
}

In above code I am trying to get RGB color.In that problem is some cell color have no background (NO Fill) but the color.getTriplet() is returning 0,0,0 ie black background color.How to differentiate and get the original background color.

Answer 1

Excel cell fills are pattern fills. The fill foreground color is the color of the pattern and the fill background color is the color behind the pattern.

So only if there is a fill pattern at all, the colors are meaningful, else not. So do determining whether a cell is filled by getting the fill pattern and not by the color.

Do CellStyle.getFillPattern and then only if FillPatternType is not FillPatternType.NO_FILL , then the cell is filled.

In current apache poi versions you will do:

...
CellStyle cellStyle = cell.getCellStyle();
FillPatternType patternType = cellStyle.getFillPattern();
if (patternType  != FillPatternType.NO_FILL) {
 short colorIdx = cellStyle.getFillForegroundColor();
 ...

In the ancient apache poi 3.9 the CellStyle.getFillPattern returns a short . So it would must be:

...
CellStyle cellStyle = cell.getCellStyle();
short patternType = cellStyle.getFillPattern();
if (patternType  != 0) {
 short colorIdx = cellStyle.getFillForegroundColor();
 ...