把excel导入的自定义时间改成yyyyMMdd

public static String changeCellToString(XSSFCell cell){
String result = "";
// Object value = null;
DecimalFormat df = new DecimalFormat("#");
if (null != cell) {
switch (cell.getCellType()) {
case HSSFCell.CELL_TYPE_NUMERIC:// 数字类型
if (HSSFDateUtil.isCellDateFormatted(cell)) {// 处理日期格式、时间格式
SimpleDateFormat sdf = null;
if (cell.getCellStyle().getDataFormat() == HSSFDataFormat
.getBuiltinFormat("h:mm")) {
sdf = new SimpleDateFormat("HH:mm");
} else {// 日期
sdf = new SimpleDateFormat("yyyyMMdd");
}
Date date = cell.getDateCellValue();
result = sdf.format(date);
} else if (cell.getCellStyle().getDataFormat() == 58) {
// 处理自定义日期格式：m月d日(通过判断单元格的格式id解决，id的值是58)
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
double value = cell.getNumericCellValue();
Date date = org.apache.poi.ss.usermodel.DateUtil
.getJavaDate(value);
result = sdf.format(date);
} else {
double value = cell.getNumericCellValue();
CellStyle style = cell.getCellStyle();
DecimalFormat format = new DecimalFormat();
String temp = style.getDataFormatString();
// 单元格设置成常规
if (temp.equals("General")) {
format.applyPattern("#");
}
result = format.format(value);
}
break;
case HSSFCell.CELL_TYPE_STRING:// String类型
result = cell.getRichStringCellValue().toString();
break;
case HSSFCell.CELL_TYPE_BLANK:
result = "";
default:
result = "";
break;
}
}
return result;
}