在POI中为合并的单元格创建边框

Question

任何人都可以解释我如何使用Apache POI为合并的单元格创建边框？
我正在使用的代码只影响一个单元格.

sheet.addMergedRegion(new CellRangeAddress(1, 1, 2, 3));
Cell monthCell = subheaderRow.createCell(2);
monthCell.setCellValue(2);
monthCell.setCellStyle(styles.get("month"));



style = wb.createCellStyle();

style.setBorderBottom(CellStyle.BORDER_THIN);
style.setBorderTop(CellStyle.BORDER_THIN);
style.setBorderLeft(CellStyle.BORDER_THIN);
style.setBorderRight(CellStyle.BORDER_THIN);
style.setAlignment(CellStyle.ALIGN_CENTER);
style.setAlignment(CellStyle.ALIGN_CENTER);
style.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
// style.setFillForegroundColor(IndexedColors.DARK_BLUE.getIndex());
// style.setFillPattern(CellStyle.SOLID_FOREGROUND);
// style.setFont(monthFont);
styles.put("month", style);

Answer 1

这可以通过以下方式完成:

public void doMerge(int rowIndex, int columnIndex, int rowSpan, int columnSpan) {
    Cell cell = sheet.getRow(rowIndex).getCell(columnIndex);
    CellRangeAddress range = new CellRangeAddress(rowIndex, rowIndex + rowSpan - 1, columnIndex, columnIndex
            + columnSpan - 1);

    sheet.addMergedRegion(range);

    RegionUtil.setBorderBottom(cell.getCellStyle().getBorderBottom(), range, sheet, sheet.getWorkbook());
    RegionUtil.setBorderTop(cell.getCellStyle().getBorderTop(), range, sheet, sheet.getWorkbook());
    RegionUtil.setBorderLeft(cell.getCellStyle().getBorderLeft(), range, sheet, sheet.getWorkbook());
    RegionUtil.setBorderRight(cell.getCellStyle().getBorderRight(), range, sheet, sheet.getWorkbook());

    RegionUtil.setBottomBorderColor(cell.getCellStyle().getBottomBorderColor(), range, sheet, sheet.getWorkbook());
    RegionUtil.setTopBorderColor(cell.getCellStyle().getTopBorderColor(), range, sheet, sheet.getWorkbook());
    RegionUtil.setLeftBorderColor(cell.getCellStyle().getLeftBorderColor(), range, sheet, sheet.getWorkbook());
    RegionUtil.setRightBorderColor(cell.getCellStyle().getRightBorderColor(), range, sheet, sheet.getWorkbook());
}