删除NULL指针EXception

Question

我正在尝试将一个Excel工作表的内容复制到另一个工作表中，而不使用Java中的Apache POI将格式应用于单元格。但是我在LINE中抛出了一个NULL指针异常 switch (cell.getCellType()) {
为什么会出现此错误？

 import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;

    import org.apache.poi.xssf.usermodel.XSSFCell;
    import org.apache.poi.xssf.usermodel.XSSFRow;
    import org.apache.poi.xssf.usermodel.XSSFSheet;
    import org.apache.poi.xssf.usermodel.XSSFWorkbook;

    public class Automate {

        public static void main(String[] args) {
            // TODO Auto-generated method stub
            final File myFile = new File(
                    "sample.xlsx");
            FileInputStream fis;
            try {
                fis = new FileInputStream(myFile);
                // Finds the workbook instance for XLSX file
                final XSSFWorkbook wb = new XSSFWorkbook(fis);
                // Return first sheet from the XLSX workbook
                XSSFSheet sheet = wb.getSheetAt(0);
                System.out.println(sheet.getLastRowNum());
                XSSFWorkbook outWorkbook = getFilteredWorkBook(sheet);

                // save merged file
                File outFile = new File("C:\\filtered.xlsx");
                if (!outFile.exists()) {
                    outFile.createNewFile();
                }
                FileOutputStream out = new FileOutputStream(outFile);
                outWorkbook.write(out);
                out.close();
                System.out.println("Files were created successfully");

            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }

        private static XSSFWorkbook getFilteredWorkBook(XSSFSheet sheet) {
            // TODO Auto-generated method stub
            XSSFWorkbook workbook = new XSSFWorkbook();
            XSSFSheet outSheet = workbook.createSheet();
            int i = 0;
            for (int rowCount = 0; rowCount < sheet.getLastRowNum(); rowCount++) {
                System.out.println(rowCount);
                XSSFRow outRow = outSheet.createRow(i);
                XSSFRow row = sheet.getRow(rowCount);
                int j = 0;

                for (int colCount = 0; colCount < 10; colCount++) {
                    System.out.println(colCount);
                    XSSFCell outCell = outRow.createCell(j);
                    XSSFCell cell = row.getCell(colCount);
                    switch (cell.getCellType()) {
                    case XSSFCell.CELL_TYPE_FORMULA:
                        outCell.setCellFormula(cell.getCellFormula());
                        break;
                    case XSSFCell.CELL_TYPE_NUMERIC:
                        outCell.setCellValue(cell.getNumericCellValue());
                        break;
                    case XSSFCell.CELL_TYPE_STRING:
                        outCell.setCellValue(cell.getStringCellValue());
                        break;
                    case XSSFCell.CELL_TYPE_BLANK:
                        outCell.setCellType(XSSFCell.CELL_TYPE_BLANK);
                        break;
                    case XSSFCell.CELL_TYPE_BOOLEAN:
                        outCell.setCellValue(cell.getBooleanCellValue());
                        break;

                    default:
                        outCell.setCellValue(cell.getStringCellValue());
                        break;
                    }

                }
            }
            return workbook;
        }

    }