Kết Nối:

  public static Connection layketnoi()
    {
        String url = "jdbc:sqlserver://localhost:1433;databaseName=QLSanPham;encrypt=true;trustServerCertificate=true";
        String user="sa";
        String pass="123";
        Connection ketNoi = null;
        try {
            ketNoi = DriverManager.getConnection(url,user,pass);
            System.out.println("Da ket noi thanh cong");
        } catch (Exception e) {
            System.out.println("Khong the ket noi database");
        }
        return ketNoi;
    }

Lấy dữ liệu:

public void laydulieuSP()
    {
        String sql = "SELECT * from SanPham";
        DefaultTableModel model = (DefaultTableModel) jTableSP.getModel();
        Vector vt;
        model.setNumRows(0);
        try {
            Connection ketNoi = ConnectJDBC.layketnoi();
            PreparedStatement ps = ketNoi.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            while(rs.next())
            {
                vt = new Vector();
                vt.add(rs.getString("MaSP"));
                vt.add(rs.getString("NameSP"));
                vt.add(rs.getString("NgayNhap"));
                vt.add(rs.getString("NgayHetHan"));
                vt.add(rs.getString("GiaBan"));
                model.addRow(vt);
            }
            jTableSP.setModel(model);
            ps.close();
            rs.close();
            ketNoi.close();
        } catch (Exception e) {
            System.out.println("Khong the ket Noi database" + e.getMessage());
        }
    }

Thêm dữ liệu:

public void ThemSP(String ma,String name,String ngaynhap,String ngayhethan,String giaban)  
      {
          String sql = "INSERT INTO SanPham Values(?,?,?,?,?)";
          try {
            Connection ketNoi = ConnectJDBC.layketnoi();
            PreparedStatement ps = ketNoi.prepareStatement(sql);
            ps.setString(1, ma);
            ps.setString(2, name);
            ps.setString(3,ngaynhap);
            ps.setString(4,ngayhethan);
            ps.setString(5,giaban);
            ps.executeUpdate();
            ps.close();
            ketNoi.close();
              JOptionPane.showMessageDialog(null, "Them Thanh Cong");
          } catch (Exception e) {
              System.out.println("Khong the ket noi database" +e.getMessage());
          }
      }

Xóa dữ liệu

 public void xoadulieuNV()
       {
           String sql = "DELETE from NhanVien Where MaNV = ?";
           int i = jTableNhanVien.getSelectedRow();
           String a = (String) jTableNhanVien.getValueAt(i, 0);
           try {
               Connection ketNoi = ConnectJDBC.layketnoi();
                PreparedStatement ps = ketNoi.prepareStatement(sql);
                ps.setString(1,a );
                ps.executeUpdate();
                JOptionPane.showMessageDialog(null, "Xoa Thanh Cong");
           } catch (Exception e) {
               System.out.println("Khong the ket noi database" + e.getMessage());
           }
       }

Sửa dữ liệu:

 public void suadulieuSP(String ten,String ngaynhap,String ngayhethan,String giaban)
       {
           String sql = "UPDATE SanPham SET NameSP =? ,NgayNhap =?,NgayHetHan=?,GiaBan=? where MaSP =?";
           int i = jTableSP.getSelectedRow();
           String a = (String) jTableSP.getValueAt(i, 0);
             try {
               Connection ketNoi = ConnectJDBC.layketnoi();
                PreparedStatement ps = ketNoi.prepareStatement(sql);
                ps.setString(1,ten );
                ps.setString(2,ngaynhap);
                ps.setString(3,ngayhethan);
                ps.setString(4,giaban);
                ps.setString(5,a);
                ps.executeUpdate();
                JOptionPane.showMessageDialog(null, "CapNhatThanhCong");
           } catch (Exception e) {
               System.out.println("Khong the ket noi database" + e.getMessage());
           }
       }

Check:

   public static boolean checkTrung(String id)
    {
        String sql = "SELECT * from HocVien where MaHV = ?";
        try {
        Connection ketNoi = connection.layketnoi();
        PreparedStatement ps = ketNoi.prepareStatement(sql);
        ResultSet rs = ps.executeQuery();
        if(rs.next())
        {
            return false;
        }else
        {
            return true;
        }
        } catch (Exception e) {
        }
        return true;
    }
    public static boolean checkEmail(String email)
    {
        String regex = "^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\\.[a-zA-Z]{2,}$";
        if(email.matches(regex))
        {
            return true;
        }else
        {
            return false;
        }
    }
    public static boolean checksdt(String sdt)
    {
        String regex = "^(\\+84|0)(3|5|7|8|9)[0-9]{8}$";
        if(sdt.matches(regex))
        {
            return true;
        }
        return false;
    }
    public static boolean checkrong(String user)
    {
         if(user.trim().isEmpty())
          {
//              jTextFieldTaiKhoan.setBorder(BorderFactory.createLineBorder(Color.RED));
//              check =false;
          }
         return true;
    }
    public void checkcccd(String a)
    {
    String regex = "^[0-9]{12}$";
    
    }
Thêm Mã Tự Động:
   String sql1 = "SELECT COUNT(MaSach) from Sach"; 
              Connection ketNoi = connection.layketnoi();
              PreparedStatement psdem = ketNoi.prepareStatement(sql);
              ResultSet rs = psdem.executeQuery();
              rs.next();
              int count  = rs.getInt(1);
              String ma1 = String.format("MS%03d", ++count);