How to refresh data in Jscrollpane bound with jtable?

Question

My code is working when I directly use jtable, but when I bound it with scroll panel, it runs one time. After another click on button it hides the data. Here is the code:

import java.awt.ScrollPane;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

import javax.swing.*;
import javax.swing.table.DefaultTableModel;

import com.mysql.jdbc.Statement;

class Scrl extends JFrame implements ActionListener 
{
    JScrollPane sp;
    Icon back,front;
    JLabel l,l1;
    JTable tb=new JTable();
    DefaultTableModel model;
    String column[]={"JobcardNo","Customer Name","Brand","Date","PhoneNo"};
    JTextField jobt=new JTextField("");
    JButton b=new JButton("click");


    public Scrl()

    {
        b.setBounds(200,140,100,20);
        jobt.setBounds(114,50,100,20);
        model = new DefaultTableModel();
        tb.setModel(model); 
        model.setColumnIdentifiers(column);
        add(jobt);
        add(b);


        b.addActionListener(this);


        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setResizable(false);
        setLocationRelativeTo(null);
        setLayout(null);
        setSize(700,600);
        setVisible(true);
        setLocationRelativeTo(null);
    }

    @Override
    public void actionPerformed(ActionEvent e) 
    {
        if(e.getSource()==b)
        {
            String job_no=jobt.getText();

            try
            {
                Class.forName("com.mysql.jdbc.Driver");
                Connection    con=DriverManager.getConnection("jdbc:mysql://localhost:3306/ac_data","root","root");
                java.sql.Statement st=con.createStatement();
                ResultSet rs=st.executeQuery("select * from main");
                while(rs.next())
                {
                    String hey=rs.getString(1);
                    if(hey.equals(job_no))
                    {
                         System.out.println(rs.getString(2));
                        String jobno=rs.getString(1);
                        String names=rs.getString(2);
                        String brand=rs.getString(21);
                        String date=rs.getString(6);
                        String phoneno=rs.getString(4);
                        model.addRow(new Object[]{jobno,names,brand,date,phoneno});                         
                    }
                }   
            }

            catch(Exception ee)
            {                   
            }

        }
        JScrollPane sp=new JScrollPane(tb);
        sp.setBounds(1,165,687,440);
        add(sp);
    }
    public static void main(String[] args) 
    {
        new Scrl();
    }
}

Scroll panel is not refreshing data itslef.

Answer 1

1. You don't close the Connection when you're finished.

2. You should read the information from your database once, before you construct the GUI, and put the information into a TableModel.

3. You're trying to place all of the Swing components by hand when you should be using a layout manager.

4. You're not putting your Swing components on the Event Dispatch thread.

That should be enough reading and studying to keep you busy for a while.