我正在尝试使用 Apache POI 更新现有的 Excel 文件。每次运行代码时,我都会收到如下所示的错误。我也尝试过 FileInputStreamNewFile 的东西。
Exception in thread "main" java.lang.NullPointerException
at com.gma.test.WriteExcelTest.writeXLSXFile(WriteExcelTest.java:26)
at com.gma.test.WriteExcelTest.main(WriteExcelTest.java:44)
请找到下面的代码。感谢你的帮助。
package com.gma.test;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class WriteExcelTest {
public static void writeXLSXFile(int row, int col) throws IOException {
try {
FileInputStream file = new FileInputStream("C:\\Anuj\\Data\\Data.xlsx");
XSSFWorkbook workbook = new XSSFWorkbook(file);
XSSFSheet sheet = workbook.getSheetAt(0);
Cell cell = null;
//Update the value of cell
cell = sheet.getRow(row).getCell(col);
cell.setCellValue("Pass");
file.close();
FileOutputStream outFile =new FileOutputStream(new File("C:\\Anuj\\Data\\Data.xlsx"));
workbook.write(outFile);
outFile.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
writeXLSXFile(3, 3);
}
}
如果你更换
//Update the value of cell
cell = sheet.getRow(row).getCell(col);
cell.setCellValue("Pass");
With
//Retrieve the row and check for null
HSSFRow sheetrow = sheet.getRow(row);
if(sheetrow == null){
sheetrow = sheet.createRow(row);
}
//Update the value of cell
cell = sheetrow.getCell(col);
if(cell == null){
cell = sheetrow.createCell(col);
}
cell.setCellValue("Pass");
它会起作用的!
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