行= sheet.getRow（rowNumber）即使在Excel工作表中存在行時也會返回java.lang.nullpointer異常。我正在使用Apache POI

Question

編輯：我正在使用此代碼來讀取excel表的行和列。但標有雙星的行引發異常（java.lang.nullpointer異常）。此外，我也想轉換在兩欄之間找到空列，空欄。請幫助。

有2個循環一個用於行和內部用於列的明顯。 Niehter該行正在讀取，也沒有空白單元格問題得到解決。

public void read(String filePath) throws NullPointerException { 

        try { 
        FileInputStream file = new FileInputStream(new File(filePath)); 
        System.out.println("going to create Workbook object to read excel row wise");// Create Workbook instance holding reference to .xlsx file 
        XSSFWorkbook workbook = new XSSFWorkbook(file); 
        System.out.println("going to create object sheet to read excel row wise"); 
        XSSFSheet sheet = workbook.getSheetAt(0); //extracts the first sheet of excel 
        System.out.println("Running row iterator to read excel row wise"); 

        for (int rowNumber = sheet.getFirstRowNum(); rowNumber <= sheet.getLastRowNum(); rowNumber++) { 
         if (rowNumber == sheet.getFirstRowNum())// this row was skipped as it was header row. 
         { 
         System.out.println("skipping first row"); 
         continue; 
         } 
         this.rowconcat = ""; // all values of perticular row will be concatinated in this variable. 
         this.flag = 0; 

         if (sheet.getRow(rowNumber) == null) { 
          System.out.println("row detected null"); 
         } else { 
          // The row has data 
          System.out.println("row no inside else==="+rowNumber); 
          **Row row = sheet.getRow(rowNumber);** //This line here throws null pointer exception. 
         for (int cellNumber = row.getFirstCellNum(); cellNumber <= row.getLastCellNum(); cellNumber++) { 
          Cell cell = row.getCell(cellNumber); 
          if (cell == null || cell.getCellType() == Cell.CELL_TYPE_BLANK) { 
           this.flag = 1; // set to 1 to indicate blank cell but this also doesn't work 
           cell.setCellType(Cell.CELL_TYPE_STRING); 
           cell.setCellValue(" "); //inserting space in cell after converting its type to String. 
           this.rowconcat = this.rowconcat + cell.getStringCellValue() + "~"; 
          } else { 
           cell.setCellType(Cell.CELL_TYPE_STRING); 
           this.rowconcat = this.rowconcat + cell.getStringCellValue() + "~"; 
           } 
          } 
         } 
        } 
       }//try block closure 
       catch(Exception e){ 
       //autogenerated 
       } 
      } // function closure 

Answer 1

我推薦JXL庫更好的appache之一，我已經用它sinc拉長時間。它唯一的小問題是，它只適用於xls而不是xlsx（如果沒有更新發生到現在！）。

有一個小例子：

File xlsFile; 
public void manageData() 
{ 
     Workbook w; 
     try { 
      w = Workbook.getWorkbook(xlsFile); 
      // Get the first sheet 
      Sheet sheet = w.getSheet(0); 
      int j = 1; 
      //Begin from the second row 
      while (j < sheet.getColumns()) { 
       //staff 
       Cell infoCell = sheet.getCell(j, 4); 
       System.out.println(infoCell.getContents()); 
      } 
     catch (Exception e) 
     { 
     } 
}