Apache POI 无法替换空白 Excel 单元格

Question

I am currently reading values from an excel spreadsheet and assigning this value to a String variable.
Below is a sample of the code I am using:

        Workbook workbook = new XSSFWorkbook(iStream);
        Sheet firstSheet = workbook.getSheetAt(0);
        Iterator<Row> iterator = firstSheet.iterator();
        // Skips the header row
        iterator.next();

        // Iterate through the first sheet and get the cell values
        while (iterator.hasNext()) {

            Row nextRow = iterator.next();
            Iterator<Cell> cellIterator = nextRow.cellIterator();

            while (cellIterator.hasNext()) {

                Cell cell = cellIterator.next();
                int columnIndex = cell.getColumnIndex();

                switch (columnIndex) {
                case 0:
                    String userName;
                    if (cell.getStringCellValue() == "") {
                        userName = "BlankCell";
                    } else {
                        userName = cell.getStringCellValue();
                    }                       
                    break;
                }

I have multiple blank cells within this excel spreadsheet which I am trying to replace with the phrase "BlankCell".
I have used this piece of code successfully in the past but for some reason it does not work anymore.
Is my logic in this instance wrong for replacing blank cells?

Answer 1

The string comparison by == isn't good practice, there's equals method for this.

String userName;
if ("".equals(cell.getStringCellValue())) {
    userName = "BlankCell";
} else {
    userName = cell.getStringCellValue();
}