java - 使用Apache POI进行读/写

我最近才开始使用Apache POI进行一些出色的读写操作，但我遇到了一个问题。我有一个提交按钮，用于读取表单文本字段并将其打印到excel文件中：

            HSSFWorkbook workbook = new HSSFWorkbook();
    HSSFSheet sheet = workbook.createSheet("Reservations");

        Map<String, Object[]> data = new TreeMap<String, Object[]>();

        data.put("1", new Object[] {"Reservation ID", "NAME", "ARRIVAL DATE", "LENGTH OF STAY","HOME ADDRESS", "EMAIL", "PHONE NUMBER" ,"RESERVATION TYPE"});
        data.put("2", new Object[] {1, advanceLastField.getText(), arrivalDateForm.getText(), stayNum.getText(),advanceAddressForm.getText(), advanceEmailForm.getText(),advancePhoneForm.getText(),"D"});

        Set<String> keyset = data.keySet();
        int rownum = 0;
        for (String key : keyset){
            Row row = sheet.createRow(rownum++);
            Object [] objArr = data.get(key);
            int cellnum = 0;
            for (Object obj : objArr){
                Cell cell = row.createCell(cellnum++);
                if(obj instanceof String)
                    cell.setCellValue((String)obj);
                else if(obj instanceof Integer)
                    cell.setCellValue((Integer)obj);
            }

        }
        try{
            FileOutputStream out = new FileOutputStream(new File("testSheet.xls"),true);
            workbook.write(out);
            out.close();
            System.out.println("Advance Reservation succesfully written");
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    }
    }catch(NumberFormatException e){
        parsable1=false;
    }

这可以正常工作，但是我的问题是稍后尝试更新excel工作表。这是我的更新代码：

            FileInputStream inp = new FileInputStream(new File("testSheet.xls"));
        HSSFWorkbook wb = new HSSFWorkbook(inp);
        HSSFSheet sheet = wb.getSheetAt(0);
        if(idLookup.getText() == "1"){
            if(updateNameForm.getText()!= null){
                Row row = sheet.getRow(1);
                Cell cell = row.getCell(1);
                cell.setCellType(CellType.STRING);
                cell.setCellValue(updateNameForm.getText());
            }
        }
FileOutputStream fileOut = new FileOutputStream("testSheet.xls",true);
wb.write(fileOut);
fileOut.close();

谁能给我一些见识或指导？谢谢！

最佳答案

您正在将数据追加到文件。我假设您要重新创建工作表。

public FileOutputStream(String name, boolean append) throws FileNotFoundException

  append-如果为true，则字节将被写入文件的末尾
  而不是开始


另外，在重用文件之前，请确保关闭输入流

inp.close();

FileOutputStream fileOut = new FileOutputStream("testSheet.xls");
wb.write(fileOut);
fileOut.close();