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，此方法检查其存在后应检查工作簿是否为空。如果为空，则创建新工作表名称“sheet1”;如果没有，请检查此工作簿中名为“sheet1”的任何工作表。如果是，则向工作表添加新行;如果没有，请创建工作表名称“sheet1”。以下是我目前的代码，我认为这不是实现目标的正确方法：

    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);

我遇到的问题。

for循环显然不符合我的目标。有没有办法在一个if语句中同时检查空电子表格或命名电子表格？

e.g。

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

我不断收到电子表格未初始化的错误，但如果删除for循环，错误就会消失。

Answer 1

我用以下代码解决了我的问题：

    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);

Answer 2

您可以使用

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表中，则返回-1；如果工作表中存在工作表，则返回Index。

Answer 3

您已将工作簿声明为final，它不能是工作的首字母！

Answer 4

您的代码先验是错误的。您可能会为自己的答案加分？

public XSSFSheet factorySheet(final String name) {
         return Optional.ofNullable((XSSFSheet) workbook.getSheet(name))
                .orElseGet(()->(XSSFSheet) workbook.createSheet(name));
    }

Java Check工作簿包含特定的电子表格或不使用Apache POI

4 个答案: