Having an issue with event handling - sql database & java gui

Question

HI all, have posted this on another forum but I think this is the correct one to post on. I am trying to construct this hybrid of java and mysql. the data comes from a mysql database and I want it to display in the gui. this I have achieved thus far. However I have buttons that sort by surname, first name, ID tag etc....I need event handlers for these buttons but am quite unsure as to how to do it. any help would be much appreciated. Thanks in advance.
/* Student Contact Database GUI
* Phillip Wells
import java.awt.BorderLayout;     
// imports java class. All import class statements tell the compiler to use a class that is defined in the Java API.
// Borderlayout is a layout manager that assists GUI layout.
import javax.swing.*;               // imports java class. Swing enables the use of a GUI.
import javax.swing.JOptionPane;     // imports java class. JOptionPane displays messages in a dialog box as opposed to a console window.
import javax.swing.JPanel;          // imports java class. A component of a GUI.
import javax.swing.JFrame;          // imports java class. A component of a GUI.
import javax.swing.JButton;          // imports java class. A component of a GUI.
import javax.swing.JScrollPane;     // imports java class. A component of a GUI.
import javax.swing.JTable;          // imports java class. A component of a GUI.
import java.awt.*;               // imports java class. Similar to Swing but with different components and functions.
import java.awt.event.*;          // imports java class. Deals with events.
import java.awt.event.ActionEvent;     // imports java class. Deals with events.
import java.awt.event.ActionListener;     // imports java class. Deals with events.
import java.sql.*;               // imports java class. Provides API for accessing and processing data stored in a data source.
import java.util.*;               // imports java class. Contains miscellaneous utility classes such as strings.
public class studentContact extends JFrame {     // public class declaration. The �public� statement enables class availability to other java elements. 
private JPanel jContentPane; // initialises content pane
private JButton snam, id, fname, exit; // initialises Jbuttons
String firstname = "firstname"; //initialises String firstname
String secondname = "secondname"; //initialises String
public studentContact() {
Vector columnNames = new Vector();      // creates new vector object. Vectors are arrays that are expandable.
Vector data = new Vector();
initialize();
try {
// Connect to the Database
String driver = "com.mysql.jdbc.Driver"; // connect to JDBC driver
String url = "jdbc:mysql://localhost/Studentprofiles"; //location of Database
String userid = "root"; //user logon information for MySQL server
String password = "";     //logon password for above
Class.forName(driver); //reference to JDBC connector
Connection connection = DriverManager.getConnection(url, userid,
password);     // initiates connection
// Read data from a table
String sql = "Select * from studentprofile order by "+ firstname;
//SQL query sent to database, orders results by firstname.
Statement stmt = connection.createStatement
(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
//statement to create connection.
//Scroll sensitive allows movement forth and back through results.
//Concur updatable allows updating of database.
ResultSet rs = stmt.executeQuery(sql); // executes SQL query stated above and sets the results in a table
ResultSetMetaData md = rs.getMetaData();     // used to get the properties of the columns in a ResultSet object.
int columns = md.getColumnCount(); //
for (int i = 1; i <= columns; i++) {
columnNames.addElement(md.getColumnName(i));     // Get column names
while (rs.next()) {
Vector row = new Vector(columns);          // vectors data from table
for (int i = 1; i <= columns; i++) {     
row.addElement(rs.getObject(i));     // Get row data
data.addElement(row);     // adds row data
rs.close();     
stmt.close();
} catch (Exception e) {     // catches exceptions
System.out.println(e);     // prints exception message
JTable table = new JTable(data, columnNames) {     //constructs JTable
public Class getColumnClass(int column) {     
for (int row = 0; row < getRowCount(); row++) {
Object o = getValueAt(row, column);
if (o != null) {
return o.getClass();
return Object.class;
JScrollPane scrollPane = new JScrollPane( table ); // constructs scrollpane 'table'
getContentPane().add(new JScrollPane(table), BorderLayout.SOUTH); //adds table to a scrollpane
private void initialize() {
this.setContentPane(getJContentPane());
this.setTitle("Student Contact Database");     // sets title of table
ButtonListener b1 = new ButtonListener();     // constructs button listener
snam = new JButton ("Sort by surname");     // constructs Jbutton
snam.addActionListener(b1);     // adds action listener
jContentPane.add(snam);          //adds button to pane
id = new JButton ("Sort by ID");     // constructs Jbutton
id.addActionListener(b1);     // adds action listener
jContentPane.add(id);          //adds button to pane
fname = new JButton ("Sort by first name");     // constructs Jbutton
fname.addActionListener(b1);     // adds action listener
jContentPane.add(fname);          //adds button to pane
exit = new JButton ("Exit");     // constructs Jbutton
exit.addActionListener(b1);     // adds action listener
jContentPane.add(exit);          //adds button to pane
private JPanel getJContentPane() {
if (jContentPane == null) {
jContentPane = new JPanel();          // constructs new panel
jContentPane.setLayout(new FlowLayout());     // sets new layout manager
return jContentPane;     // returns Jcontentpane
private class ButtonListener implements ActionListener {     // create inner class button listener that uses action listener
public void actionPerformed (ActionEvent e)
if (e.getSource () == exit)     // adds listener to button exit.
System.exit(0);     // exits the GUI
if (e.getSource () == snam)
if (e.getSource () == id)
if (e.getSource () == fname)
public static void main(String[] args) {     // declaration of main method
studentContact frame = new studentContact();     // constructs new frame
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);     //exits frame on closing
frame.setSize(600, 300);          // set size of frame
frame.setVisible(true);     // displays frame
}

Answer 1

OK, so you've got this code here:
private class ButtonListener implements ActionListener {
  public void actionPerformed (ActionEvent e) {
    if (e.getSource () == exit) {
      System.exit(0); // exits the GUI
    if (e.getSource () == snam) {
    if (e.getSource () == id) {
}Perfect fine way to do this; although I think creating anonymous would be a bit cleaner:
snam.addActionListener(new actionListener() {
  public void actionPerformed(ActionEvent ae) {
});But I think that the real question you have is "what do I put for logic when the JButtons are hit?", right?
I would answer that you want to dynamically build your SQL statement changing your ordering based on the button.
So you'd have a method that builds the SQL based on what you pass in - so it takes one argument perhaps?
private static final int NAME = 1;
                         ID = 2;
/* ... some code ... */
snam.addActionListener(new actionListener() {
  public void actionPerformed(ActionEvent ae) {
    buildSQL(NAME);
/* ... some code ... */
private void buildSQL(int type) {
  if ( type == NAME ) {
/* ... build SQL by name ... */
  else if ( type == ID ) {
/* ... build SQL by id ... */
}That kind of thing.
Or you might choose to have several build methods with no parameter type; each building the SQL differently, and calling whichever one you need. I did not read your entire pgm, so I don't know how you'd want to organize it. You need to ask more specific questions at that point.
~Bill