Java swings

[anup v]

This is my code, i want to know by adding or modifying what can i have my code refresh the JTable everytime its accessed.

package library2;

import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.Statement;
import java.util.Vector;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.TableModelEvent;
import javax.swing.event.TableModelListener;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;

public class home extends JFrame {

protected static final ListSelectionEvent ListSelectionEvent = null;

static JFrame mainfram = new JFrame("welcome to library");

static JFrame f2 = new JFrame("LIST OF THE BOOKS");
static JButton b1 = new JButton("Add A New Book");
static JButton b2 = new JButton("Modify The Book Details");
static JButton b3 = new JButton("List Of Available Books");
static JButton lihp = new JButton("HOMEPAGE");
static JLabel l1 = new JLabel(
".............WELCOME TO LIBRARY..............", JLabel.CENTER);
static JLabel l2 = new JLabel("HAVE A GREAT DAY :)))", JLabel.CENTER);
static JPanel p1 = new JPanel(new GridLayout(5, 3, 40, 40));

public home() {
p1.setVisible(true);
b1.setSize(50, 100);

mainfram.setSize(800, 400);
mainfram.add(p1);
mainfram.setVisible(true);

// f2.add(lihp);

}

public static void main(String args[]) {
{

b1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
mainfram.setVisible(false);
mainfram.setDefaultCloseOperation(JFrame.EXIT_ON_C LOSE);

Addingbook ab = new Addingbook();
// ab.setVisible(true);
// ab.setSize(800, 400);

}

});

b2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
mainfram.setVisible(false);
mainfram.setDefaultCloseOperation(JFrame.EXIT_ON_C LOSE);

listing li = new listing();
// li.setVisible(true);
// li.setSize(800, 400);

}

});

b3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {

Vector columnNames = new Vector();
Vector data = new Vector();
data.clear();
JPanel p = new JPanel(); /* (new GridLayout(2,1,10,10) */
p.setBounds(0, 0, 400, 300);
JLabel l = new JLabel();

try {

// Connection con =
// DriverManager.getConnection("Jdbc:Odbc:test");

String sql = "select *from books";
String cs = "jdbc:mysql://localhost:3306/test";
String user = "root";
String pwd = "thbs123!";
Class.forName("com.mysql.jdbc.Driver").newInstance ();
Connection con = DriverManager.getConnection(cs, user,
pwd);

Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery(sql);
ResultSetMetaData md = rs.getMetaData();
// md.getServerExecutions();
int columns = md.getColumnCount();
for (int i = 1; i <= columns; i++) {
columnNames.addElement(md.getColumnName(i));
}
while (rs.next()) {
Vector row = new Vector(columns);
for (int i = 1; i <= columns; i++) {
row.addElement(rs.getObject(i));

}
data.addElement(row);
}
rs.close();
stmt.close();
} catch (Exception e1) {
System.out.println(e1);
}

JTable table = new JTable(data, columnNames);

//data = getServerExecutions();
//table.fireTableDataChanged();
// table.getModel().setModel();
// table.valueChanged(ListSelectionEvent);




//data(set);
// columnNames();

TableColumn col;
for (int i = 0; i < table.getColumnCount(); i++) {
col = table.getColumnModel().getColumn(i);
col.setMaxWidth(999);

}

JScrollPane scrollPane = new JScrollPane(table);
table.setPreferredScrollableViewportSize(new Dimension(750,
275));
p.setVisible(true);
p.add(l);

p.add(scrollPane);
// p.add(lihp);

f2.add(p);

f2.setSize(800, 400);
f2.setVisible(true);

}
});
f2.add(lihp);
lihp.setBounds(320, 320, 120, 30);
lihp.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {

mainfram.setVisible(true);
f2.setVisible(false);
// f2.setDefaultCloseOperation(EXIT_ON_CLOSE);

}
});

mainfram.setLayout(new FlowLayout());
// mainfram.imageUpdate(Blue, arg1, arg2, arg3, arg4, arg5)
mainfram.setVisible(true);
mainfram.setSize(800, 400);
p1.add(new JLabel(""));
p1.add(l1);
p1.add(new JLabel(""));
p1.add(new JLabel(""));
p1.add(b1);

p1.add(new JLabel(""));
p1.add(new JLabel(""));
p1.add(b2);
p1.add(new JLabel(""));
p1.add(new JLabel(""));
p1.add(b3);
p1.add(new JLabel(""));
p1.add(new JLabel(""));
p1.add(l2);
p1.add(new JLabel(""));
mainfram.add(p1);

// f2.setLayout(new FlowLayout());

f2.setResizable(false);

}

}

public void setVisible(boolean b) {
// TODO Auto-generated method stub

}
}

[rotaryfreak]

if you want to have your table reflect changes once the user manipulates it, you can apply the observer pattern

http://en.wikipedia.org/wiki/Observer_pattern

or you can simply call update() or updateUI() on your JTable every time the user manipulates the table.

i would also recommend that you refactor some of your code into separate classes so it's a little more organized. For example, i would have one class that deals with sql connections, another class for database manipulation, another class for user interface creation and another class for handling what happens when the action listeners are clicked.

hope this helps