写一个新单元格到表apache poi

我正在使用以下代码,使用apache poi读取excel,它是一个.xlsx文件.请让我知道我能做什么,也可以在我的循环继续进行的每一行中改变一个单元格的值.谢谢

import java.io.FileInputStream;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

String fileName = "C:/createCDN.xlsx";
FileInputStream fis = null;
fis = new FileInputStream(fileName);
XSSFWorkbook workbook = new XSSFWorkbook(fis);
FileOutputStream fos=new FileOutputStream(fileName);
XSSFSheet sheet = workbook.getSheetAt(0);
int totalRows=sheet.getLastRowNum();
for(int i=1;i<=totalRows;i++) {
    XSSFRow row = sheet.getRow(i);
    method.fillTextBox(row.getCell(0),"name", pageProp);
    method.fillTextBox(row.getCell(0),"name", pageProp);
} //Do something here, or inside loop to write to lets say cell(2) of same row.

谢谢.