JTable is empty after succesfully retrieving data from SQL Server

Question

So, I am trying to insert data retrieved from my SQL Server (i used WamppServer) and I noticed that everything I do wont appear in the JTable, even though the data is correctly retrieved from the server.

I am posting the whole code because I assume my issue is with the Panel Creation and not from the data insertion.

import java.awt.*;
import java.lang.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.table.*;


public class MyWindow {

    private JFrame frame,frame2,frame3,frame4;
    private JTextArea textArea_3,textArea_3_2;
    public static Connection connection = null;
    public static Statement statement = null;
    public static String sql = null;
    public static ResultSet rs = null;
    public JTable table;


    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MyWindow window = new MyWindow();
                    window.frame.setVisible(true);
                    connection = null;
                    statement = null;
                    try
                    {
                        System.out.println("conneting to Database...");
                        Class.forName("com.mysql.jdbc.Driver");                                                  //  Register JDBC driver
                        connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/efefe?autoReconnect=true&useSSL=false","root",""); //  Open connection
                        System.out.println("Connection Successful"); 
                    }
                    catch(ClassNotFoundException error)
                    {
                        System.out.println("Error:" + error.getMessage()); 
                    }

                    catch(SQLException error)
                    {
                        System.out.println("Error:" + error.getMessage());
                    }
                    finally
                    {
                        if (connection != null) 
                            try {
                                connection.close();
                                }
                        catch(SQLException ignore)
                        {

                        }

                        if (statement != null) 
                            try {
                                statement.close();
                                }

                        catch(SQLException ignore)
                        {

                        }
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        );
    }

    public MyWindow() {
        initialize();
    }


    public void initialize() {
        frame = new JFrame();
        frame3 = new JFrame();
        frame.setBounds(100, 100, 450, 300);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JButton btnNewButton = new JButton("BUTTON2");
        btnNewButton.setBounds(133, 21, 121, 23);
        frame.getContentPane().add(btnNewButton);
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                 frame3 = new JFrame(); // frame 3 is the new opening window
                 frame3.setVisible(true);
                 frame3.setBounds(200, 300, 550, 300);
                 frame3.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); // no need to close the whole app, just the new window
                 frame3.getContentPane().setLayout(null);
                 try
                 {
                        connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/efefe?autoReconnect=true&useSSL=false","root",""); //  Open connection
                        statement = connection.createStatement();            
                        sql = "SELECT * FROM customer";
                        rs = statement.executeQuery(sql);                   
                        while (rs.next()) {
                           int code  = rs.getInt("code");
                           String gender = rs.getString("gender");
                           String birthday = rs.getString("birthday");
                           String status = rs.getString("status");
                           table = new JTable();
                           table.setBounds(15, 123, 500, 120);
                           frame3.getContentPane().add(table);
                           table.setVisible(true);
                           ResultSetMetaData metaData = rs.getMetaData();
                           Vector<String> columnNames = new Vector<String>();
                           int columnCount = metaData.getColumnCount();
                               for (int column = 1; column <= columnCount; column++) {
                                         columnNames.add(metaData.getColumnName(column));
                               }
                           Vector<Vector<Object>> data = new Vector<Vector<Object>>();
                           System.out.println("DATA RETRIEVED FROM SERVER");
                           while (rs.next()) {
                               Vector<Object> vector = new Vector<Object>();
                                   for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                                         vector.add(rs.getObject(columnIndex));
                               }
                               data.add(vector);
                               System.out.println(vector);
                          }
                          System.out.println("JTable has " + table.getRowCount() + " rows!");    // 0 = empty
                          System.out.println("JTable has " + table.getColumnCount() + " columns!"); // 0 = empty
                        }
                        rs.close();                    
                        statement.close();             
                        connection.close();            
                 }
                 catch(SQLException error)
                 {
                        System.out.println("Error:" + error.getMessage());
                 }
             }
        });

     }
}

The app is supposed to open a new window when Button2 is pressed and show the JTable(that white space on the new window is the JTable).

Execution Results on my PC:

conneting to Database...
Connection Successful
DATA RETRIEVED FROM SERVER
[102, female, 1995-02-24, single]
[103, male, 1985-12-04, married]
[104, female, 1987-10-08, married]
[105, female, 1977-09-01, married]
[106, male, 1994-05-30, single]
[107, female, 1990-06-30, single]
[108, male, 1994-07-24, single]
[109, female, 1991-05-10, single]
[110, male, 2001-07-12, single]
JTable has 0 rows!
JTable has 0 columns

EDIT: Code used for JTable filling was copied from this accepted answer

Why not use `DefaultTableModel` to insert data into table? Its more easier imo. — Jaskaranbir Singh, Aug 05 '16 at 23:39
it was my previous try, but again I saw nothing come out on the JTable — ceid-vg, Aug 05 '16 at 23:40
Can I see your code for the previous try with DefaultTableModel? Doesn't have to be complete block; I am interested in how you applied TableModel to table and how did you add data to TableModel. — Jaskaranbir Singh, Aug 05 '16 at 23:44
http://stackoverflow.com/questions/10620448/most-simple-code-to-populate-jtable-from-resultset — ceid-vg, Aug 05 '16 at 23:46
I have added a snippet, see if that works? I haven't personally tested code though. — Jaskaranbir Singh, Aug 06 '16 at 00:10

score 3 · Accepted Answer · answered Aug 06 '16 at 00:08

This is a rough snippet for only one column. If it works, you can extend it to all columns. Note: Not tested personally.

DefaultTableModel model = new DefaultTableModel();

Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/efefe?autoReconnect=true&useSSL=false","root","");

ResultSet rs = connection.createStatement().executeQuery("SELECT * FROM customer");

tableModel.addColumn("gender");

int row = 0;

while (rs.next()) {
    tableModel.addRow(new Object[] {});
    tableModel.setValueAt(rs.getString("gender"), row, 0);
    row++;
}

table.setModel(tableModel);

JTable is empty after succesfully retrieving data from SQL Server

1 Answers1