不正确的整数值：如何将我的数据从String转换为Int以避免Auto_Increment？

Question

Im having troubles converting my String to integer. My Data Table consist of 3 columns, two of which are INT type. But when i started inserting my String to my Database it gives an Auto_Increment error:

Class:

public class Strong extends javax.swing.JFrame {

  String a;

    public Apply() {
        initComponents();
         jTable1.getSelectionModel().addListSelectionListener(new ListSelectionListener()
        {
            @Override
            public void valueChanged(ListSelectionEvent e)
            {
                int selectedRow = jTable1.getSelectedRow();
                a = (String) jTable1.getValueAt(selectedRow, 0);


            }
        }
        );

    }

My executeUpdate:

try{

           Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/application","root","");
            String sql= "insert into Mycart values(?,?,?)";
            PreparedStatement pst = con.prepareStatement(sql);            
            pst.setString(1, (String)a);
            pst.setString(2, (String)a);
            pst.setString(3, (String)a);

            pst.executeUpdate();
            JOptionPane.showMessageDialog(null, "Added to Cart");

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

This is actually a follow up regarding my previous question. My Question is that how can i convert my String to Integer and then insert it on my Database? If you might ask i got my String from my jTable which then got it from my database. What i want to do now is that get the values inside that jTable and insert it to a new Database.

Answer 1

You can convert a String to an Integer by using the Integer.toString() method. Just pass the string in as the parameter.

Answer 2

Try to cast object to string as below

 String a = String.valueOf(jTable1.getValueAt(selectedRow, 0)); 

 pst.setString(1, a);

In case Your target field type is integer do this.

 pst.setInt(1,Integer.ParseInt(a));

Answer 3

By assuming that your auto_increment field is you primary key and you're trying to put the first value there, it is better try this.

        String sql= "insert into Mycart (your_string_field, your_int_field) values(?,?)";
        PreparedStatement pst = con.prepareStatement(sql);
        pst.setString(1, "your_data_goes_here"); // for string
        pst.p.setInt(2, Integer.parseInt("your_data_goes here")); // for integer

        pst.executeUpdate();
        JOptionPane.showMessageDialog(null, "Added to Cart");

Note :- For auto increment fields in databases, you don't need to add a value in inserting. That is why it is called auto_increment. So I removed first field so the second field became your first prepared statement parameter.

Hope it helps.