Search in the Database

Question

I’m in doubt on a role of how to do a comic search. It’s going to catch. Can anyone tell why? And how to solve?

That is the function

public void consultar(){
    String sql ="select * from tbaluno where idaluno=?";
    try {
         PreparedStatement stmt = connection.prepareStatement(sql);
         stmt.setString(1, textid.getText());
         rs = stmt.executeQuery();
         if(rs.next())

         System.out.println(textid);
         if(rs.next()){
             Usuario usuario = new Usuario();
             usuario.setNomealuno(rs.getString("nomealuno"));
             txtnome.setText(rs.getString(2));  
         }else{

         }
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e);
    }
}

The message that appears when I put an existing id in the database: java.lang.NullPointerException

EDIT-> Mysql Table, Contains:

ID | Name

1 | Vinicius

I wanted when I put the id 1, to show in the field the name "Vinicius". The change I made in the function consult above, was just remove one if and exchange the other by while.

Answer 1

Probably in your table there are more things than nomealuno one of them must be the idaluno, which comes before.

Once the program runs it goes through the only if effective (although there is one more) and cannot access the column of the name, generating a Nullpointer.

Try trading the if for one while(rs.next()) since you select all attributes in select. Or change select to just name