Apache POI: How to write numbers in scientific format

Question

I want to write numbers to Excel in scientific notation. In Apache Poi it is possible to set the number format of a cell like this:

Cell cell = ...
CellStyle style = workbook.createCellStyle();
DataFormat format = workbook.createDataFormat();
style.setDataFormat(format.getFormat("#0.00"));
cell.setCellStyle(style);

But when I use a pattern like "#0.00E0" I get an error from Excel when opening the file and the number format is lost.

Here is a full example:

import java.io.FileOutputStream;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.DataFormat;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class Main {
    public static void main(String[] args) {
        try (Workbook wb = new XSSFWorkbook();
            FileOutputStream fos = new FileOutputStream("out.xlsx")) {
            Sheet sheet = wb.createSheet();
            Cell cell = sheet.createRow(0).createCell(0);
            CellStyle style = wb.createCellStyle();
            DataFormat format = wb.createDataFormat();
            style.setDataFormat(format.getFormat("#0.00E0"));
            cell.setCellStyle(style);
            cell.setCellValue(Math.random());
            wb.write(fos);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Thanks!

Answer 1

科学计数法的正确格式为：

format.getFormat("0.00E+00")