displaying data from database in JTable

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Hello everybody!
Can anyone tell me the code for how to display data from table in database in a JTable in java. I am using java 1.5 and MS-Access.
 

JGuru

Wise Old Owl
@Peyosh, Here goes the answer to your question.

Here is the JAVA code for JDBC Connectivity:

//This will fetch the data from a table & display the output in a JTable


//JDBCAdapter.java
/*
* @(#)JDBCAdapter.java 1.16
*/

/**
* An adaptor, transforming the JDBC interface to the TableModel interface.
*
* @version 1.20
* @author JGuru
*/

import java.util.Vector;
import java.sql.*;
import javax.swing.table.AbstractTableModel;
import javax.swing.event.TableModelEvent;

public class JDBCAdapter extends AbstractTableModel {
Connection connection;
Statement statement;
ResultSet resultSet;
String[] columnNames = {};
Vector rows = new Vector();
ResultSetMetaData metaData;

public JDBCAdapter(String url, String driverName,
String user, String passwd) {
try {
Class.forName(driverName);
System.out.println("Opening db connection");

connection = DriverManager.getConnection(url, user, passwd);
statement = connection.createStatement();
}
catch (ClassNotFoundException ex) {
System.err.println("Cannot find the database driver classes.");
System.err.println(ex);
}
catch (SQLException ex) {
System.err.println("Cannot connect to this database.");
System.err.println(ex);
}
}

public void executeQuery(String query) {
if (connection == null || statement == null) {
System.err.println("There is no database to execute the query.");
return;
}
try {
resultSet = statement.executeQuery(query);
metaData = resultSet.getMetaData();

int numberOfColumns = metaData.getColumnCount();
columnNames = new String[numberOfColumns];
// Get the column names and cache them.
// Then we can close the connection.
for(int column = 0; column < numberOfColumns; column++) {
columnNames[column] = metaData.getColumnLabel(column+1);
}

// Get all rows.
rows = new Vector();
while (resultSet.next()) {
Vector newRow = new Vector();
for (int i = 1; i <= getColumnCount(); i++) {
newRow.addElement(resultSet.getObject(i));
}
rows.addElement(newRow);
}
// close(); Need to copy the metaData, bug in jdbc:eek:dbc driver.
fireTableChanged(null); // Tell the listeners a new table has arrived.
}
catch (SQLException ex) {
System.err.println(ex);
}
}

public void close() throws SQLException {
System.out.println("Closing db connection");
resultSet.close();
statement.close();
connection.close();
}

protected void finalize() throws Throwable {
close();
super.finalize();
}

//////////////////////////////////////////////////////////////////////////
//
// Implementation of the TableModel Interface
//
//////////////////////////////////////////////////////////////////////////

// MetaData

public String getColumnName(int column) {
if (columnNames[column] != null) {
return columnNames[column];
} else {
return "";
}
}

public Class getColumnClass(int column) {
int type;
try {
type = metaData.getColumnType(column+1);
}
catch (SQLException e) {
return super.getColumnClass(column);
}

switch(type) {
case Types.CHAR:
case Types.VARCHAR:
case Types.LONGVARCHAR:
return String.class;

case Types.BIT:
return Boolean.class;

case Types.TINYINT:
case Types.SMALLINT:
case Types.INTEGER:
return Integer.class;

case Types.BIGINT:
return Long.class;

case Types.FLOAT:
case Types.DOUBLE:
return Double.class;

case Types.DATE:
return java.sql.Date.class;

default:
return Object.class;
}
}

public boolean isCellEditable(int row, int column) {
try {
return metaData.isWritable(column+1);
}
catch (SQLException e) {
return false;
}
}

public int getColumnCount() {
return columnNames.length;
}

// Data methods

public int getRowCount() {
return rows.size();
}

public Object getValueAt(int aRow, int aColumn) {
Vector row = (Vector)rows.elementAt(aRow);
return row.elementAt(aColumn);
}

public String dbRepresentation(int column, Object value) {
int type;

if (value == null) {
return "null";
}

try {
type = metaData.getColumnType(column+1);
}
catch (SQLException e) {
return value.toString();
}

switch(type) {
case Types.INTEGER:
case Types.DOUBLE:
case Types.FLOAT:
return value.toString();
case Types.BIT:
return ((Boolean)value).booleanValue() ? "1" : "0";
case Types.DATE:
return value.toString(); // This will need some conversion.
default:
return "\""+value.toString()+"\"";
}

}

public void setValueAt(Object value, int row, int column) {
try {
String tableName = metaData.getTableName(column+1);
// Some of the drivers seem buggy, tableName should not be null.
if (tableName == null) {
System.out.println("Table name returned null.");
}
String columnName = getColumnName(column);
String query =
"update "+tableName+
" set "+columnName+" = "+dbRepresentation(column, value)+
" where ";
// We don't have a model of the schema so we don't know the
// primary keys or which columns to lock on. To demonstrate
// that editing is possible, we'll just lock on everything.
for(int col = 0; col<getColumnCount(); col++) {
String colName = getColumnName(col);
if (colName.equals("")) {
continue;
}
if (col != 0) {
query = query + " and ";
}
query = query + colName +" = "+
dbRepresentation(col, getValueAt(row, col));
}
System.out.println(query);
System.out.println("Not sending update to database");
// statement.executeQuery(query);
}
catch (SQLException e) {
// e.printStackTrace();
System.err.println("Update failed");
}
Vector dataRow = (Vector)rows.elementAt(row);
dataRow.setElementAt(value, column);

}
}

The second file is as follows:
//TableExample.java
/*
* @(#)TableExample.java
*/

/**
* A a UI around the JDBCAdaptor, allowing database data to be interactively
* fetched, sorted and displayed using Swing.
*
* NOTE: This example uses a modal dialog via the static convenience methods in
* the JOptionPane. Use of modal dialogs requires JDK 1.1.4 or greater.
*
* @version 1.19
* @author JGuru
*/

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;
import javax.swing.border.*;

public class TableExample implements LayoutManager {
static String[] ConnectOptionNames = { "Connect" };
static String ConnectTitle = "Connection Information";

Dimension origin = new Dimension(0, 0);

JButton fetchButton;
JButton showConnectionInfoButton;

JPanel connectionPanel;
JFrame frame; // The query/results window.

JLabel userNameLabel;
JTextField userNameField;
JLabel passwordLabel;
JTextField passwordField;
// JLabel queryLabel;
JTextArea queryTextArea;
JComponent queryAggregate;
JLabel serverLabel;
JTextField serverField;
JLabel driverLabel;
JTextField driverField;

JPanel mainPanel;

TableSorter sorter;
JDBCAdapter dataBase;
JScrollPane tableAggregate;

/**
* Brings up a JDialog using JOptionPane containing the connectionPanel.
* If the user clicks on the 'Connect' button the connection is reset.
*/
void activateConnectionDialog() {
if(JOptionPane.showOptionDialog(tableAggregate, connectionPanel, ConnectTitle,
JOptionPane.DEFAULT_OPTION, JOptionPane.INFORMATION_MESSAGE,
null, ConnectOptionNames, ConnectOptionNames[0]) == 0) {
connect();
frame.setVisible(true);
}
else if(!frame.isVisible())
System.exit(0);
}

/**
* Creates the connectionPanel, which will contain all the fields for
* the connection information.
*/
public void createConnectionDialog() {
// Create the labels and text fields.
userNameLabel = new JLabel("User name: ", JLabel.RIGHT);
userNameField = new JTextField("guest");

passwordLabel = new JLabel("Password: ", JLabel.RIGHT);
passwordField = new JTextField("trustworthy");

serverLabel = new JLabel("Database URL: ", JLabel.RIGHT);
serverField = new JTextField("jdbc:eek:dbc:mydsn");
//Where 'mydsn' is the DSN (Data Source Name you have created using the ODBC icon in Windows Control Panel.
driverLabel = new JLabel("Driver: ", JLabel.RIGHT);
driverField = new JTextField("sun.jdbc.odbc.JdbcOdbcDriver");


connectionPanel = new JPanel(false);
connectionPanel.setLayout(new BoxLayout(connectionPanel,
BoxLayout.X_AXIS));

JPanel namePanel = new JPanel(false);
namePanel.setLayout(new GridLayout(0, 1));
namePanel.add(userNameLabel);
namePanel.add(passwordLabel);
namePanel.add(serverLabel);
namePanel.add(driverLabel);

JPanel fieldPanel = new JPanel(false);
fieldPanel.setLayout(new GridLayout(0, 1));
fieldPanel.add(userNameField);
fieldPanel.add(passwordField);
fieldPanel.add(serverField);
fieldPanel.add(driverField);

connectionPanel.add(namePanel);
connectionPanel.add(fieldPanel);
}

public TableExample() {
mainPanel = new JPanel();

// Create the panel for the connection information
createConnectionDialog();

// Create the buttons.
showConnectionInfoButton = new JButton("Configuration");
showConnectionInfoButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
activateConnectionDialog();
}
}
);

fetchButton = new JButton("Fetch");
fetchButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
fetch();
}
}
);

// Create the query text area and label.
queryTextArea = new JTextArea("SELECT * FROM titles", 25, 25);
queryAggregate = new JScrollPane(queryTextArea);
queryAggregate.setBorder(new BevelBorder(BevelBorder.LOWERED));

// Create the table.
tableAggregate = createTable();
tableAggregate.setBorder(new BevelBorder(BevelBorder.LOWERED));

// Add all the components to the main panel.
mainPanel.add(fetchButton);
mainPanel.add(showConnectionInfoButton);
mainPanel.add(queryAggregate);
mainPanel.add(tableAggregate);
mainPanel.setLayout(this);

// Create a Frame and put the main panel in it.
frame = new JFrame("TableExample");
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}});
frame.setBackground(Color.lightGray);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setVisible(false);
frame.setBounds(200, 200, 640, 480);

activateConnectionDialog();
}

public void connect() {
dataBase = new JDBCAdapter(
serverField.getText(),
driverField.getText(),
userNameField.getText(),
passwordField.getText());
sorter.setModel(dataBase);
}

public void fetch() {
dataBase.executeQuery(queryTextArea.getText());
}

public JScrollPane createTable() {
sorter = new TableSorter();

//connect();
//fetch();

// Create the table
JTable table = new JTable(sorter);
// Use a scrollbar, in case there are many columns.
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);

// Install a mouse listener in the TableHeader as the sorter UI.
sorter.addMouseListenerToHeaderInTable(table);

JScrollPane scrollpane = new JScrollPane(table);

return scrollpane;
}

public static void main(String s[]) {
new TableExample();
}

public Dimension preferredLayoutSize(Container c){return origin;}
public Dimension minimumLayoutSize(Container c){return origin;}
public void addLayoutComponent(String s, Component c) {}
public void removeLayoutComponent(Component c) {}
public void layoutContainer(Container c) {
Rectangle b = c.getBounds();
int topHeight = 90;
int inset = 4;
showConnectionInfoButton.setBounds(b.width-2*inset-120, inset, 120, 25);
fetchButton.setBounds(b.width-2*inset-120, 60, 120, 25);
// queryLabel.setBounds(10, 10, 100, 25);
queryAggregate.setBounds(inset, inset, b.width-2*inset - 150, 80);
tableAggregate.setBounds(new Rectangle(inset,
inset + topHeight,
b.width-2*inset,
b.height-2*inset - topHeight));
}

}

Both the 2 files are needed for Compiling & running the program.
To Compile:

javac TableExample.java

To run:

java TableExample

You must also configure & create a new DSN from the 'ODBC' icon
in the Control Panel.

See JDBC Tutorial Click here :http://java.sun.com/docs/books/tutorial/jdbc/basics/index.html

Also see JDBC 2.0 Fundamentals Tutorial Click here : http://java.sun.com/developer/onlineTraining/Database/DBC20Intro/JDBC20.html


Also see How to use Tables : http://java.sun.com/docs/books/tutorial/uiswing/components/table.html

You also need to study & understand JFC(Java Foundation Classes).
 
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