如果java中的特定列为null,则不从excel插入mysql

我正在尝试将excel工作表数据插入mysql db。如果列中有数据,一切都会正常工作。但如果列为null,则程序停止执行,并且不会插入数据。

下面是我如何插入excel数据

测试PP。Java语言

    public class TestApp {
    public static void main(String[] args) throws Exception {
    try {
    Class forName = Class.forName("com.mysql.jdbc.Driver");
    Connection con = null;
    con = 
    DriverManager.getConnection("jdbc:mysql://192.168.1.13:3307/db1",
    "sachin-LH", "s123");
    con.setAutoCommit(false);
    PreparedStatement pstm = null;
    FileInputStream input = new 
    FileInputStream("C:\\Users\\lh\\Downloads\\Student Details(2009-
    13).xls");
    POIFSFileSystem fs = new POIFSFileSystem(input);
    Workbook workbook;
    workbook = WorkbookFactory.create(fs);
    Sheet sheet = workbook.getSheetAt(0);
    Row row;
    for (int i = 1; i <= sheet.getLastRowNum(); i++) {
        row = (Row) sheet.getRow(i);
        String name = row.getCell(0).getStringCellValue();
        String email = row.getCell(1).getStringCellValue();
        String sql = "INSERT INTO user
        (firstName,email) VALUES('" + name + 
      "','"+email+"')";
        pstm = (PreparedStatement) con.prepareStatement(sql);
        pstm.execute();
        System.out.println("Import rows " + i);
    }
    con.commit();
    pstm.close();
    con.close();
    input.close();
    System.out.println("Success import excel to mysql table");
    } catch (IOException e) {
    }
    }
    }

我的Excel工作表

    Name  email
    test  test@gmail.com
    john  ----
    mike  mike@gmail.com

第二行没有电子邮件,我收到空指针异常。如果特定列中不存在值,有人能告诉我如何插入空值吗。?