Question

I have a MySql table in which I have a column named payslip_no which is set as an AUTO_INCREMENT. I want to set this auto incremented value to the value of a text box at the time of page load.

Another way is I am trying to increment this number programatically without setting the column as ‘AUTO_INCREMENT’. Following is the code:

public void get_payslip_no()
{

int n1 =0;
try
{
rs2=st2.executeQuery("select max(payslip_no) from tbl_add_payroll");
if(rs2.next())
{
n1=rs2.getInt("payslip_no");
n1=n1+1;
String n2 = Integer.toString(n1);
txt_payslip_no.setText(n2);
System.out.println(n2);                   
}
}//try
catch(SQLException e2)
{
 JOptionPane.showMessageDialog(this,"Payroll-Serial no Storing Error!!!","Serial No Error",JOptionPane.INFORMATION_MESSAGE);    
}//catch
}

This code is throwing A NullPointerException because the current database is null. How might I resolve this?

Answer 1

You can try this answer..:)

int no=101;
    int no1;
try
        {
           dbStatement = con.createStatement();
           dbResult= dbStatement.executeQuery("select payslip_no from tbl_add_payroll ORDER BY  payslip_no  DESC LIMIT 1");

          if(dbResult.next()==false)
          {
               jTextField3.setText(String.valueOf(no));

          }
         else
          {         
            dbResult= dbStatement.executeQuery("select payslip_no from tbl_add_payroll ORDER BY payslip_no DESC LIMIT 1");      
                    while(dbResult.next())

                           {
                           deptno=dbResult.getInt("payslip_no");

                             }


                             no1=deptno+1;
                             jTextField3.setText(String.valueOf(no1));
          }


     }catch(Exception E)
     {

     }