Question

我想使用Java和apache库poi将String写入现有的Excel文件单元格。这是我的方法：

public void setSuccessMessageInExcellFile(File uploadFile, HttpServletResponse response) {          

    try {
        FileInputStream fileInputStream = new FileInputStream(uploadFile);

        HSSFWorkbook workbook = new HSSFWorkbook(fileInputStream);
        HSSFSheet excelSheet = workbook.getSheetAt(0); 
        HSSFCell cell = excelSheet.getRow(0).getCell(0);
        cell.setCellValue("Imported");

        fileInputStream.close();
        FileOutputStream out = new FileOutputStream(uploadFile);
        workbook.write(out);
        out.close();
    } catch(Exception ex) {
        ex.getCause().printStackTrace();
    }           
}

我的 Excel 文件中没有错误，但“已导入”文字不可用。

Answer 1

确保您的文件存在，可写并且具有正确的Excel版本。在那之后你应该改变你的代码，因为你得到的是NullPointerException：

public void setSuccessMessageInExcellFile(File uploadFile, HttpServletResponse response) {


    try {
        FileInputStream fileInputStream = new FileInputStream(uploadFile);

        HSSFWorkbook workbook = new HSSFWorkbook(fileInputStream);
        HSSFSheet excelSheet = workbook.getSheetAt(0); 
        HSSFCell cell = excelSheet.createRow(0).createCell(0);
        cell.setCellValue("Imported");

        fileInputStream.close();
        FileOutputStream out = new FileOutputStream(uploadFile);
        workbook.write(out);
        out.close();
    } catch(Exception ex) {
        ex.getCause().printStackTrace();
    } 
}

更好的做法就是把关闭点放在try中作为参数：

try(FileInputStream fileInputStream = new FileInputStream(uploadFile);
            HSSFWorkbook workbook = new HSSFWorkbook(fileInputStream); 
            FileOutputStream out = new FileOutputStream(uploadFile)) {            
        HSSFSheet excelSheet = workbook.getSheetAt(0); 
        HSSFCell cell = excelSheet.createRow(0).createCell(0);
        cell.setCellValue("Imported"); 
        workbook.write(out);         
    } catch(Exception ex) {
        ex.getCause().printStackTrace();
    }

无法将数据写入Excel文件单元格

1 个答案: