Java检查工作簿包含特定的电子表格或未使用Apache POI

Question

我正在使用apache POI创建一个包含多个电子表格的Excel文件。首先，此方法应在检查工作簿是否存在后检查工作簿是否为空。如果为空，请创建新的工作表名称“sheet1”；如果不是，请检查此工作簿中任何名为“sheet1”的工作表。如果是，则向工作表添加新行；如果不是，请创建一个工作表名称“sheet1”。以下是我当前的代码，我认为这不是实现我目标的正确方法：

    File file = new File("Main Data.xlsx");
    // Retrieve the workbook for the main report
    XSSFWorkbook workbook;
    // Check file existence 
    if (file.exists() == false) {
        // Create new file if it does not exist
        workbook = new XSSFWorkbook();
    } else {
        try ( 
            // Make current input to exist file
            InputStream is = new FileInputStream(file)) {
                workbook = new XSSFWorkbook(is);
            }
    }
    XSSFSheet spreadsheet;
    // Check if the workbook is empty or not
    if (workbook.getNumberOfSheets() != 0) {
        for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
           if (workbook.getSheetName(i).equals(" Enc " + deviceLabel.getText() + " Info. ")) {
                spreadsheet = workbook.getSheet(" Enc " + deviceLabel.getText() + " Info. ");
            } else spreadsheet = workbook.createSheet(" Enc " + deviceLabel.getText() + " Info. ");
        }
    }
    else {
        // Create new sheet to the workbook if empty
        spreadsheet = workbook.createSheet(" Enc " + deviceLabel.getText() + " Info. ");
    }

    // Error here (variable spreadsheet may not have been initialized
    spreadsheet.shiftRows(0, spreadsheet.getLastRowNum(), 23);   

我遇到的拖曳问题。

< Li > for循环显然是错误的，无法实现我的目标。有什么方法可以让我在一个if语句中同时检查空电子表格或已命名电子表格是否存在？

例如

  if ((workbook.getNumberOfSheets() == 0) && !workbook.getSheet("sheet1").exists()) {
    workbook.createSheet("sheet1");
  } else workbook.getSheet("sheet1")

Answer 1

您已将工作簿声明为最终版本，它不能是工作的初始版本！

Answer 2

您可以简单地检查是否创建了工作表

workbook.getSheetIndex(sheetName)

如果工作表不在工作簿中，则返回-1；如果工作簿中存在，则返回索引。

Answer 3

我发现了以下代码的问题：

    File file = new File("Main Data.xlsx");
    // Retrieve the workbook for the main report
    XSSFWorkbook workbook;
    // Check file existence 
    if (file.exists() == false) {
        // Create new file if it does not exist
        workbook = new XSSFWorkbook();
    } else {
        try ( 
            // Make current input to exist file
            InputStream is = new FileInputStream(file)) {
                workbook = new XSSFWorkbook(is);
            }
    }
    XSSFSheet spreadsheet = workbook.getSheet("sheet1");
    // Check if the workbook is empty or not
    if (workbook.getNumberOfSheets() != 0) {
        for (int i = 0; i < workbook.getNumberOfSheets(); i++) {
           if (workbook.getSheetName(i).equals("sheet1")) {
                spreadsheet = workbook.getSheet("sheet1");
            } else spreadsheet = workbook.createSheet("sheet1");
        }
    }
    else {
        // Create new sheet to the workbook if empty
        spreadsheet = workbook.createSheet("sheet1");
    }

    // Shift rows down if exist
    spreadsheet.shiftRows(0, spreadsheet.getLastRowNum(), 23);