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Display database table with swing (Columns names do not show up) [duplicate]

I'm making a GUI Project for database there are two classes which are for GUI's. And connector class is used to connect from user credentials. If credentials are correct than it fetch all data in the from of AbstractTableModel. When program run first GUI has a button in which we click it and it fetch all data in underlying TableModel. But i'm facing two problems. First in GUI2 class, sometimes it open like this.
and sometimes it show like this
I don't know why it's happening. And second problem is when we select any row from table and click on DeleteSelectedRow button it delete the row. This button has a ActionListener in GUI2 class. But what i want is i automatic update the table when row has been deleted. How can i do that?
class for first GUI
public class Gui extends JFrame {
private static Connector conni;
private Connection conn = null;
private JButton bt;
private JPanel panel;
public Gui() {
super("Frame");
panel = new JPanel();
bt = new JButton("Connect to Database 'World'");
panel.add(bt);
bt.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
conn = conni.Connector();
if (conn != null) {
dispose();
new Gui2(conn);
} else {
System.out.println("Return false");
}
}
});
add(panel);
pack();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
}
Connector class
public class Connector {
private static Connection conn = null;
public static Connection Connector() {
String data = "jdbc:mysql://localhost/world";
String user = "root";
String pass = "toot";
try {
conn = DriverManager.getConnection(data, user, pass);
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.getMessage());
}
if (conn != null) {
System.out.println("Connection Suceess");
return conn;
} else {
return conn;
}
}
}
class for second GUI2
public class Gui2 extends JFrame {
private Statement state = null;
private ResultSet rs = null;
private JButton bt, delete;
private JTextField text;
private JPanel panel;
private GridBagLayout layout;
private GridBagConstraints constraints;
public Gui2(Connection conn) {
layout = new GridBagLayout();
constraints = new GridBagConstraints();
panel = new JPanel();
panel.setLayout(layout);
text = new JTextField(15);
bt = new JButton("Submit Query");
delete = new JButton("Delete Selected Row");
constraints.insets = new Insets(5, 2, 5, 10);
constraints.gridy = 0;// row 0
constraints.gridx = 0;// column 0
// TextField add on JPanel with given constraints
panel.add(text, constraints);
constraints.gridx++;
panel.add(delete, constraints);
constraints.gridx++;
panel.add(bt, constraints);
// North BorderLayout
add(panel, BorderLayout.NORTH);
try {
state = conn.createStatement();
rs = state.executeQuery("select * from city");
} catch (SQLException e) {
JOptionPane.showMessageDialog(null, e.getMessage());
}
JTable table = new JTable();
JScrollPane spane = new JScrollPane(table);
add(spane, BorderLayout.CENTER);
table.setModel(new TableModel(rs));
delete.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
int rowIndex = table.getSelectedRow();
Object columnIndexValue = table.getModel().getValueAt(rowIndex, 0);
String columnName = table.getModel().getColumnName(0);
String query = "delete from world.city" + " where " + columnName + "=" + columnIndexValue;
try {
PreparedStatement pre = conn.prepareStatement(query);
pre.executeUpdate();
JOptionPane.showMessageDialog(null, "Row Deleted Successfully");
} catch (Exception e1) {
JOptionPane.showMessageDialog(null, e1.getMessage());
}
}
});
setSize(817, 538);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
setVisible(true);
}
}
Tablemodel Class
public class TableModel extends AbstractTableModel {
private List ColumnHeader;
private List tableData;
private List rowData;
private int totalcolumn;
public TableModel(ResultSet rs) {
try {
ResultSetMetaData meta = rs.getMetaData();
totalcolumn = meta.getColumnCount();
ColumnHeader = new ArrayList(totalcolumn);
tableData = new ArrayList();
for (int i = 1; i <= totalcolumn; i++) {
ColumnHeader.add(meta.getColumnName(i));
}
} catch (Exception e) {
JOptionPane.showMessageDialog(null, e.getMessage());
}
SwingWorker<Boolean, List<Object>> worker = new SwingWorker<Boolean, List<Object>>() {
#Override
protected Boolean doInBackground() throws Exception {
while (rs.next()) {
rowData = new ArrayList(totalcolumn);
for (int i = 1; i <= totalcolumn; i++) {
rowData.add(rs.getObject(i));
}
publish(rowData);
}
return true;
}
#Override
protected void process(List chunks) {
tableData.add(chunks);
}
#Override
protected void done() {
try {
Boolean status = get();
JOptionPane.showMessageDialog(null, "Task is DONE");
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
};
worker.execute();
}// constructor end
#Override
public int getColumnCount() {
return ColumnHeader.size();
}
public String getColumnName(int columnIndex) {
return (String) ColumnHeader.get(columnIndex);
}
#Override
public int getRowCount() {
return tableData.size();
}
#Override
public Object getValueAt(int rowIndex, int columnIndex) {
List rowData2 = (List) tableData.get(rowIndex);
return rowData2.get(columnIndex);
}
}

Because database access is inherently asynchronous, you'll surely want to retrieve rows in the background to avoid blocking the event dispatch thread; SwingWorker makes this relatively easy. Fetch rows in your implementation of doInBackground(), publish() interim results, and add them to the table model in your implementation of process(). A complete example that outlines the attendant benefits is shown here. The example loops through a file, but you can substitute your ResultSet operations.
while (rs.next()) {
//collect row data
publish(rowData);
}
Defer tableData.add() to your implementation of process().
Focusing on the interaction between the custom TableModel and its contained SwingWorker, the following complete example creates a test database having N rows and displays a JTable showing the results of a query of that table. In particular,
JDBCModel extends AbstractTableModel. For simplicity, the model's data is stored in a List<Row>, and ResultSetMetaData is used for the column names. As a more abstract alternative, see Apache Commons DbUtils, which uses Class Literals as Runtime-Type Tokens and ResultSetMetaData to safely create instances of row data.
JDBCModel delegates row retrieval to a private JDBCWorker; it invokes publish() on each row retrieved from the ResultSet; because process() runs on the EDT, the worker can optimize the number of table model events that it fires on behalf of the parent model using fireTableRowsInserted().
Similarly, your implementation of delete() should reside in JDBCModel, not the GUI; it should fireTableRowsDeleted() after the row is successfully deleted from the database and removed from data.
Add Thread.sleep() to the worker's background loop to see the effect of artificially increasing latency.
Use setProgress() and a PropertyChangeListener, shown here, to display progress; a JOptionPane when done() may be superfluous.
Override getPreferredScrollableViewportSize() to customize the size of the table's enclosing JScrollPane.
Avoid class names, e.g. TableModel, that collide with common API names.
A variation that implements live filtering in the view is examined here.
import java.awt.Dimension;
import java.awt.EventQueue;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingWorker;
import javax.swing.table.AbstractTableModel;
/**
* #see https://stackoverflow.com/a/34742409/230513
* #see https://stackoverflow.com/a/24762078/230513
*/
public class WorkerTest {
private static final int N = 1_000;
private static final String URL = "jdbc:h2:mem:test";
private static final Random r = new Random();
private void display() {
JFrame f = new JFrame("WorkerTest");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
createTestDatabase(N);
JDBCModel model = new JDBCModel(getConnection(), "select * from city");
f.add(new JScrollPane(new JTable(model) {
#Override
public Dimension getPreferredScrollableViewportSize() {
return new Dimension(320, 240);
}
}));
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
private static class Row {
int ID;
String name;
}
private static class JDBCModel extends AbstractTableModel {
private final List<Row> data = new ArrayList<>();
private ResultSet rs = null;
private ResultSetMetaData meta;
public JDBCModel(Connection conn, String query) {
try {
Statement s = conn.createStatement();
rs = s.executeQuery(query);
meta = rs.getMetaData();
JDBCWorker worker = new JDBCWorker();
worker.execute();
} catch (SQLException e) {
e.printStackTrace(System.err);
}
}
#Override
public int getRowCount() {
return data.size();
}
#Override
public int getColumnCount() {
try {
return meta.getColumnCount();
} catch (SQLException e) {
e.printStackTrace(System.err);
}
return 0;
}
#Override
public Object getValueAt(int rowIndex, int colIndex) {
Row row = data.get(rowIndex);
switch (colIndex) {
case 0:
return row.ID;
case 1:
return row.name;
}
return null;
}
#Override
public String getColumnName(int colIndex) {
try {
return meta.getColumnName(colIndex + 1);
} catch (SQLException e) {
e.printStackTrace(System.err);
}
return null;
}
private class JDBCWorker extends SwingWorker<List<Row>, Row> {
#Override
protected List<Row> doInBackground() {
try {
while (rs.next()) {
Row r = new Row();
r.ID = rs.getInt(1);
r.name = rs.getString(2);
publish(r);
}
} catch (SQLException e) {
e.printStackTrace(System.err);
}
return data;
}
#Override
protected void process(List<Row> chunks) {
int n = getRowCount();
for (Row row : chunks) {
data.add(row);
}
fireTableRowsInserted(n, n + chunks.size());
}
}
}
private static void createTestDatabase(int n) {
Connection conn = getConnection();
try {
Statement st = conn.createStatement();
st.execute("create table city(id integer, name varchar2)");
PreparedStatement ps = conn.prepareStatement(
"insert into city values (?, ?)");
for (int i = 0; i < n; i++) {
ps.setInt(1, i);
ps.setString(2, (char) ('A' + r.nextInt(26))
+ String.valueOf(r.nextInt(1_000_000)));
ps.execute();
}
} catch (SQLException ex) {
ex.printStackTrace(System.err);
}
}
private static Connection getConnection() {
try {
return DriverManager.getConnection(URL, "", "");
} catch (SQLException e) {
e.printStackTrace(System.err);
}
return null;
}
public static void main(String[] args) {
EventQueue.invokeLater(new WorkerTest()::display);
}
}

Display ResultSet of a SQL query in a JTable (Java)

I'm working on a program with which I can search through a database and display the results.
I'm stuck at the displaying part at the moment. My SQL query already works and returns the results. I'm using a PreparedStatement to fill my ResultSet. However I don't know how I can return the data of the ResultSet to a JTable which I want to use to display the data. Can anyone explain to me in detail how to do this or if there is a better way instead of a JTable I'm not seeing?
I'm using the MVC model and the DAO pattern, but I'm still pretty new to programming.
So far from researching it I found the best solution to be to make a custom table class, but from there on I don't know how to progress.
My custom table class:
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.util.Vector;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
public class ResultSetTable {
public static TableModel resultSetToTableModel(ResultSet rs) {
try {
ResultSetMetaData metaData = rs.getMetaData();
int numberOfColumns = metaData.getColumnCount();
Vector columnNames = new Vector();
//Spaltennamen
for (int column = 0; column < numberOfColumns; column++) {
columnNames.addElement(metaData.getColumnLabel(column + 1));
}
//Alle Zeilen
Vector rows = new Vector();
while (rs.next()) {
Vector newRow = new Vector();
for (int i = 1; i <= numberOfColumns; i++) {
newRow.addElement(rs.getObject(i));
}
rows.addElement(newRow);
}
return new DefaultTableModel(rows, columnNames);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
}
And the relevant part of my View class:
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.JTextField;
import dbconnect.dao.impl.BTRDaoImpl;
public class View extends JFrame{
public View() {
JTable table = new JTable(new ResultSetTable(BTRDaoImpl.resultset);
this.setSize(600, 400);
setResizable(false);
}
My BTRDaoImpl class with the sql query and resultset:
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import mvc.View;
import dao.BTRbDao;
import business.BTRBean;
public class BTRDaoImpl extends AbstractDao implements BTRDao {
private Connection dbConnection = null;
private PreparedStatement preparedStatement = null;
public void sqlquery() {
try {
String btrname = View.searchbbtrname.getText();
String btrplz = View.searchbtrplz.getText();
btrname = btrname.trim().toUpperCase();
btrplz = btrplz.trim().toUpperCase();
if (btrplz.isEmpty()) {
String btrResult = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ FROM BP.TBBBST WHERE BBSTNABEG = ?";
dbConnection = AbstractDao.getConnection();
preparedStatement = dbConnection.prepareStatement(btrResult);
preparedStatement.setString(1, btrname);
} else {
String btrResult = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ FROM BP.TBBBST WHERE BBSTNABEG = ? AND BBSTPLZ = ?";
dbConnection = AbstractDao.getConnection();
preparedStatement = dbConnection.prepareStatement(btrResult);
preparedStatement.setString(1, btrname);
preparedStatement.setString(2, btrplz);
}
} catch (SQLException e1) {
System.out.println("An error with the SQL query occured: ");
e1.printStackTrace();
}
}
public Collection<BtrBean> getBTR() throws SQLException,
IOException {
sqlquery();
final Collection<BtrBean> result = new ArrayList<BtrBean>();
ResultSet resultset = null;
try {
resultset = preparedStatement.executeQuery();
// while loop to get data
while (resultset.next()) {
BtrBean btr = new BtrBean();
int btrid = resultset.getInt(1);
String btrplz = resultset.getString(3);
String btrname = resultset.getString(2);
btr.setBetriebnr(btrid);
btr.setBetriebplz(btrplz);
btr.setBetriebname(btrname);
result.add(btr);
// System.out.println("BTR-ID: " + btrid + " BTR PLZ: " + btrplz + " BTR: " + btrname);
}
} catch (SQLException e) {
e.printStackTrace();
System.out.println("An error processing the SQL occured: ");
e.printStackTrace();
} catch (NullPointerException npe) {
System.out.println("NullPointerException: ");
npe.printStackTrace();
} finally {
if (preparedStatement != null) preparedStatement.close();
closeConnection(resultset);
}
return result;
}
}
My BTRBean class:
public class BetriebBean {
private String betriebname;
private int betriebnr;
private String betriebplz;
public BetriebBean() {
}
public BetriebBean(String betriebname, int betriebnr, String betriebplz) {
super();
this.betriebname = betriebname;
this.betriebnr = betriebnr;
this.betriebplz = betriebplz;
}
public String getBetriebname() {
return betriebname;
}
public void setBetriebname(String betriebname) {
this.betriebname = betriebname;
}
public int getBetriebnr() {
return betriebnr;
}
public void setBetriebnr(int betriebnr) {
this.betriebnr = betriebnr;
}
public String getBetriebplz() {
return betriebplz;
}
public void setBetriebplz(String betriebplz) {
this.betriebplz = betriebplz;
}
}
//edit:
My whole View.class:
import java.awt.FlowLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTable;
import javax.swing.JTextField;
public class View extends JFrame{
private static final long serialVersionUID = 1L;
public static final String SEARCH = "SEARCH";
private JLabel searchbtrlabel = new JLabel("BTR name:");
public static JTextField searchbtrname = new JTextField(10);
private JLabel searchbtrlabel = new JLabel("PLZ:");
public static JTextField searchbtrplz = new JTextField(10);
private JButton searchbutton = new JButton();
public View() {
this.setTitle("BTR search TBBBST");
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.setLayout(new FlowLayout());
this.add(searchbtrlabel);
this.add(searchbtrname);
this.add(searchbtrplzlabel);
this.add(searchbtrplz);
searchbutton.setText("Search");
searchbutton.setActionCommand(View.SEARCH);
this.add(searchbutton);
JTable table = new JTable();
this.add(table);
this.setSize(600, 400);
setResizable(false);
//this.pack();
}
public JTextField getSearchbtrname() {
return searchbetriebname;
}
public JTextField getSearchbbtrplz() {
return searchbetriebplz;
}
public JButton getSearchbutton() {
return searchbutton;
}
}
My Controller class:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Observable;
import java.util.Observer;
import mvc.Model;
import dbconnect.dao.impl.BTRDaoImpl;
public class Controller implements Observer, ActionListener{
private Model model;
#SuppressWarnings("unused")
private View view;
public Controller(Model model, View view) {
this.model = model;
this.view = view;
model.addObserver(this);
view.getSearchbutton().addActionListener(this);
view.setVisible(true);
}
#Override
public void actionPerformed(ActionEvent e) {
switch (e.getActionCommand()) {
case View.SEARCH:
model.search();
view.table.setModel(ResultSetToTable.buildTableModel(BTRDaoImpl.resultset));
break;
default:
System.out.println("Error : " + e.getActionCommand());
break;
}
}
#Override
public void update(Observable o, Object arg) {
// TODO Auto-generated method stub
}
}

Firstly, include rs2xml.jar in your libraries. You can find it here
In whatever action to populate your MySQL query in your JTable use following general idea:
public void sqlquery() {
try {
String btrResult = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ FROM BP.TBBBST WHERE BBSTNABEG = ?";
preparedStatement = dbConnection.prepareStatement(btrResult);
dbConnection.setString(1, btrname);
ResultSet rs =dbConnection.executeQuery();
Ur_table_name.setModel(DbUtils.resultSetToTableModel(DbUtils.resultSetToel(rs)); //this line of code will show it in your JTable
}catch(Exception e){
}

What is your question? Try being more specific than "[...] but from there on I don't know how to progress." What do you want to do? Are the results from your query visible in the table?
Using the answer from Paul Vargas over here Most simple code to populate JTable from ResultSet, you could start with something like this (using Java 8):
import java.sql.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.table.*;
public class ResultSetToTable {
public static void main(final String[] arguments) {
SwingUtilities.invokeLater(() -> {
try {
new ResultSetToTable().createAndShowGui();
} catch (SQLException e) {
e.printStackTrace();
}
});
}
private void createAndShowGui() throws SQLException {
final JFrame frame = new JFrame("Stack Overflow");
frame.setBounds(100, 100, 800, 600);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
final JPanel panel = new JPanel();
final TableModel tableModel = buildTableModel(getData("Audi"));
final JTable table = new JTable(tableModel);
panel.add(new JScrollPane(table));
frame.getContentPane().add(panel);
frame.setVisible(true);
}
private ResultSet getData(final String btrName) throws SQLException {
final String url = "jdbc:h2:/Freek/TBBBST";
final Connection connection = DriverManager.getConnection(url, "me", "123");
final String sql = "SELECT BBSTBBNR, BBSTNABE, BBSTPLZ " +
"FROM BP.TBBBST " +
"WHERE BBSTNABEG = ?";
final PreparedStatement preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, btrName);
return preparedStatement.executeQuery();
}
/**
* See https://stackoverflow.com/a/10625471/1694043
*/
public static TableModel buildTableModel(final ResultSet resultSet)
throws SQLException {
int columnCount = resultSet.getMetaData().getColumnCount();
// Column names.
Vector<String> columnNames = new Vector<>();
for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
columnNames.add(resultSet.getMetaData().getColumnName(columnIndex));
}
// Data of the table.
Vector<Vector<Object>> dataVector = new Vector<>();
while (resultSet.next()) {
Vector<Object> rowVector = new Vector<>();
for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
rowVector.add(resultSet.getObject(columnIndex));
}
dataVector.add(rowVector);
}
return new DefaultTableModel(dataVector, columnNames);
}
}
For older versions of Java, you should be able to use this version of the main method:
public static void main(final String[] arguments) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
new ResultSetToTable().createAndShowGui();
} catch (SQLException e) {
e.printStackTrace();
}
}
});
}
Edit: connecting controller and table
To make the table available outside the view, you need to convert the table variable in the View() constructor into a field (like you have done with searchbtrname) and create a getTable getter method for it (like you have done with getSearchbtrname). In the Controller.actionPerformed method you can now change view.table into view.getTable().

Any way to connect JTable (TableModel) with H2 database [duplicate]

This question already has answers here:
How to fill data in a JTable with database?
(7 answers)
Closed 7 years ago.
My current project is some kind of a database system that has a gui for maintenance. Before my major code rewrite, I used to serialize and de-serialize the TableModel to save and load data to the gui. Because this was not a good solution for obvious reasons I did some research and ended up using an H2 (local) database to save and load my data from.
The code used to save the data into my database can be found in my other question.
The save process itself is not the biggest problem but I can't find any good way to load the data back into my JTable (TableModel).
Is there any way to directly wire JTable (TableModel) together with any kind of SQL database? Currently using JTable with a database seems to be a really big hassle with Java.

Okay, so this is a simple example, which creates a in-memory database, with a single table and some values.
It uses a simple custom TableModel which can be "refreshed" if the underlying data is changed.
Have a closer look at JDBC Database Access for some more details
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.AbstractTableModel;
public class TestTable {
private Connection con;
public static void main(String[] args) {
new TestTable();
}
public TestTable() {
try {
Class.forName("org.h2.Driver");
String url = "jdbc:h2:mem:InMemoryTest";
con = DriverManager.getConnection(url);
createShoppingListTable();
fillShoppingListTable();
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
} catch (ClassNotFoundException | SQLException exp) {
exp.printStackTrace();
}
}
protected void createShoppingListTable() throws SQLException {
String query = "create table shoppingList (id bigint identity, item varchar(255), quantity int)";
try (Statement stmt = con.createStatement()) {
stmt.execute(query);
}
}
protected void fillShoppingListTable() throws SQLException {
String[] items = {"Bananas", "Apples", "Grapes", "Pears", "Oranges"};
Random rnd = new Random();
try (PreparedStatement ps = con.prepareStatement("insert into shoppingList (item, quantity) values (?, ?)")) {
for (String item : items) {
ps.setString(1, item);
ps.setInt(2, rnd.nextInt(100));
ps.addBatch();
}
ps.executeBatch();
}
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new BorderLayout());
TestTableModel model = new TestTableModel();
JTable table = new JTable(model);
add(new JScrollPane(table));
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
model.refresh();
} catch (SQLException ex) {
ex.printStackTrace();
}
}
});
}
}
public class TestTableModel extends AbstractTableModel {
private List<ShoppingList> shoppingList = new ArrayList<>(25);
private List<String> columnNames = new ArrayList<>(25);
#Override
public int getRowCount() {
return shoppingList.size();
}
#Override
public int getColumnCount() {
return columnNames.size();
}
#Override
public String getColumnName(int column) {
return columnNames.get(column);
}
#Override
public Object getValueAt(int rowIndex, int columnIndex) {
ShoppingList rowValue = shoppingList.get(rowIndex);
Object value = null;
switch (columnIndex) {
case 0:
value = rowValue.getId();
break;
case 1:
value = rowValue.getItem();
break;
case 2:
value = rowValue.getQuanity();
break;
}
return value;
}
public void refresh() throws SQLException {
List<String> values = new ArrayList<>(25);
try (PreparedStatement ps = con.prepareStatement("select * from shoppingList")) {
try (ResultSet rs = ps.executeQuery()) {
ResultSetMetaData md = rs.getMetaData();
for (int col = 0; col < md.getColumnCount(); col++) {
values.add(md.getColumnName(col + 1));
}
while (rs.next()) {
ShoppingList list = new ShoppingList(rs.getLong(1), rs.getString(2), rs.getInt(3));
shoppingList.add(list);
}
}
} finally {
if (columnNames.size() != values.size()) {
columnNames = values;
fireTableStructureChanged();
} else {
fireTableDataChanged();
}
}
}
public class ShoppingList {
private long id;
private String item;
private int quanity;
public ShoppingList(long id, String item, int quanity) {
this.id = id;
this.item = item;
this.quanity = quanity;
}
public long getId() {
return id;
}
public String getItem() {
return item;
}
public int getQuanity() {
return quanity;
}
}
}
}

Add ResultSet into Jtable (between two classes)

My application throws NullPointerException. I created connection between MySQL database and my second class.
I can't call DefaultTableModel by method in my second class.
How can I solve this problem?
public class MySQL extends javax.swing.JFrame {
private DefaultTableModel modelTabeli;
public MySQL(){
initComponents();
BazaDana bd = new BazaDana();
try{
modelTabeli = bd.map();
jTable1.setModel(modelTabeli);
}
catch(Exception e){
System.out.println(e.toString());
}
}
public static void main(String args[]) throws Exception{
BazaDana bd = new BazaDana();
bd.readDataBase();
}
}
Second class
import java.sql.*;
import javax.swing.table.DefaultTableModel;
public class BazaDana{
public DefaultTableModel map() throws SQLException
{
defaultTableModel = new DefaultTableModel();
int numberOfColumns = resultSetMetaData.getColumnCount();
while (resultSet.next())
{
Object [] rowData = new Object[numberOfColumns];
for (int i = 0; i < rowData.length; ++i)
{
rowData[i] = resultSet.getObject(i+1);
}
defaultTableModel.addRow(rowData);
}
return defaultTableModel;
}
}

Ok, may I give you an alternative solution if your goal is to separate GUI class from class which queries database. Don't return DefaultTableModel, return just values from ResultSet through some collection, like this:
Create MySql GUI class:
import java.awt.EventQueue;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class MySql extends JFrame{
JTable table = new JTable();
DefaultTableModel model = new DefaultTableModel(new Object[][]{},new String[]{"First column","Second column"});
public MySql(){
table.setModel(model);
add(new JScrollPane(table));
//Populate table
BazaDana bd = new BazaDana();
List<Value> values = bd.selectAll();
for(Value v : values){
model.addRow(new Object[]{v.getFirstValue(),v.getSecondValue()});
}
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable(){
public void run() {
MySql ms = new MySql();
ms.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
ms.pack();
ms.setVisible(true);
}});
}
}
Then create Java bean class:
public class Value {
private int id;
private String firstValue;
private String secondValue;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getFirstValue() {
return firstValue;
}
public void setFirstValue(String firstValue) {
this.firstValue = firstValue;
}
public String getSecondValue() {
return secondValue;
}
public void setSecondValue(String secondValue) {
this.secondValue = secondValue;
}
}
And finally your BazaDana class which queries database:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
public class BazaDana {
public List<Value> selectAll(){
Connection conn = null;
Statement st = null;
ResultSet rs = null;
//Create list of values
List<Value> values = new ArrayList<Value>();
try{
Class.forName("com.mysql.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/nameofdb","user","pass");
st = conn.createStatement();
rs = st.executeQuery("SELECT * FROM mytable");
while(rs.next()){
Value v = new Value();
v.setFirstValue(rs.getString("first_column"));
v.setSecondValue(rs.getString("second_column"));
values.add(v);
}
}
catch(Exception e){
e.printStackTrace();
}
finally{
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
st.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return values;
}
}

JTable getSelectedRow does not return the selected row index

I try to get data in the row that is selected but getSelectedRow() doesn't work. Actually, I used that method in the other class, but it works in there. When I try to print the row index; the prompt shows -1; as not selected.
I tried most of solutions that are on the internet but they didn't solve my solutions.
public Canteen() {
try {
jbInit();
} catch (Exception e) {
e.printStackTrace();
}
}
private void jbInit() throws Exception {
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.getContentPane().setLayout( null );
this.setSize( new Dimension(400, 300) );
this.setTitle( "CANTEEN" );
jScrollPane1.setBounds(new Rectangle(0, 0, 230, 235));
jButton1.setText("REFRESH");
jButton1.setBounds(new Rectangle(0, 235, 100, 20));
jButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
jButton1_actionPerformed(e);
}
});
jButton2.setText("CLOSE");
jButton2.setBounds(new Rectangle(120, 235, 110, 20));
jButton2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
jButton2_actionPerformed(e);
}
});
jScrollPane1.getViewport().add(jTable1, null);
this.getContentPane().add(jButton2, null);
this.getContentPane().add(jButton1, null);
this.getContentPane().add(jScrollPane1, null);
jTable1 = new JTable (model);
String header [] = {"CUSTOMER", "PRODUCT", "QUANTITY","ORDER NO"};
for (int i = 0; i < 4; i++){
model.addColumn(header[i]);
}
//refresh every 1 minute
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask(){
public void run(){
model.setRowCount(0);
try {
Class.forName(driverName);
conn = DriverManager.getConnection(url,username, password);
statement = conn.createStatement();
ResultSet rs = statement.executeQuery("SELECT USER_NAME, QUANTITY, PRD_NAME, ORDER_NUMBER FROM ORDERS ORDER BY ORDER_NUMBER DESC");
int count = rs.getRow();
String user [] = new String [count];
int i = 0;
while (rs.next()){
String name = rs.getString(1);
String prdName = rs.getString(3);
int number = rs.getInt(2);
int orderNumber = rs.getInt(4);
model.insertRow(i,new Object []{name,prdName,number, orderNumber});
}
conn.close();
}
catch (ClassNotFoundException s) {
System.out.println("Couldn't find the database driver");
System.out.println(s);
}
catch (SQLException s) {
System.out.println("Couldn't connect to the database\n" +s);
}
}
},0, 60000);
}
private void jButton1_actionPerformed(ActionEvent e) {
//set from row 0 for refresh
model.setRowCount(0);
try {
Class.forName(driverName);
conn = DriverManager.getConnection(url,username, password);
statement = conn.createStatement();
ResultSet rs = statement.executeQuery("SELECT USER_NAME, QUANTITY, PRD_NAME FROM ORDERS ORDER BY ORDER_NUMBER DESC");
int count = rs.getRow();
String user [] = new String [count];
int i = 0;
while (rs.next()){
String name = rs.getString(1);
String prdName = rs.getString(3);
int number = rs.getInt(2);
model.insertRow(i,new Object []{name,prdName,number});
}
conn.close();
}
catch (ClassNotFoundException s) {
System.out.println("Couldn't find the database driver");
System.out.println(s);
}
catch (SQLException s) {
System.out.println("Couldn't connect to the database\n" +s);
}
}
private void jButton2_actionPerformed(ActionEvent e) {
System.out.println(jTable1.getSelectedRow());
}
}

Look to your code
private void jbInit() throws Exception {
...
jScrollPane1.getViewport().add(jTable1, null);
this.getContentPane().add(jButton2, null);
this.getContentPane().add(jButton1, null);
this.getContentPane().add(jScrollPane1, null);
jTable1 = new JTable (model);
...
You add jTable1 to the JScrollPane at first and only then you create jTable1. It's incorrect way. jTable1 variable doen't linked now with table you place at the form. I think it's cause of your problem.
Move creation of the jTable1 before adding in into JScrollPane.
...
jTable1 = new JTable (model);
jScrollPane1.getViewport().add(jTable1, null);
this.getContentPane().add(jButton2, null);
this.getContentPane().add(jButton1, null);
this.getContentPane().add(jScrollPane1, null);
...

As your other example shows, getSelectedRow() does work, so you're going to have to debug your code. Comparison with the sscce below may suggest way forward. Both the ActionListener and the ListSelectionListener show the selected row.
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import javax.swing.table.DefaultTableModel;
/**
* #see http://stackoverflow.com/q/12301923/230513
*/
public class TableSelection extends JPanel {
private static final String SHOW = "Show";
private DefaultTableModel model = new DefaultTableModel();
private JTable table = new JTable(model);
private JButton button = new JButton(new AbstractAction(SHOW) {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(table.getSelectedRow());
}
});
public TableSelection() {
model.addColumn("Column");
for (int i = 0; i < 16; i++) {
model.addRow(new Object[]{i});
}
table.setPreferredScrollableViewportSize(new Dimension(160, 100));
table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
table.getSelectionModel().addListSelectionListener(
new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
if (!e.getValueIsAdjusting()) {
button.setText(SHOW + " " + table.getSelectedRow());
}
}
});
this.add(new JScrollPane(table));
table.setRowSelectionInterval(3, 3);
}
private void display() {
JFrame f = new JFrame("TableSelection");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(this, BorderLayout.CENTER);
f.add(button, BorderLayout.SOUTH);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new TableSelection().display();
}
});
}
}