Oracle adatbázis elérése Java nyelvű programból

import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;

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

class JDBCTestGUI extends JFrame implements ActionListener, ItemListener
{
  private JTable result_table;
  private JButton search_button;
  private TextField name_field;
  private JPanel input_panel;
  private JPanel output_panel;
  private JPanel static_main_panel;
  private DefaultTableModel table_model;
  private JScrollPane scroll_pane;
  private Vector column_names_vector;
  private Choice field_choice;
  private String choice_string;
  private JTabbedPane tabbed_pane;
  
  private ResultSet rs;
  private Statement stmt;
  
  
  /**
   *  Constuctor. Creating and initializing objects.
   * */
  public JDBCTestGUI(String title) {
	  super( title );
	  this.setSize( 600, 400 );
	  this.static_main_panel = new JPanel();
	  this.output_panel = new JPanel();
	  this.input_panel = new JPanel();
	  this.name_field = new TextField( 50 );
	  this.search_button = new JButton( "Search" );
	  this.field_choice = new Choice();
	   
	 
	  createGUI();
	  
	  try {
		  
		  /* Connect to the Oracle Database and using the "HR" user's schema */
		  OracleDataSource ods = new OracleDataSource();
  		  Class.forName ("oracle.jdbc.OracleDriver");

		  ods.setURL("jdbc:oracle:thin:@hoszt:1521:sid");
		  Connection conn = ods.getConnection("HR","HR");
		  stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);
	  } catch ( Exception ex ) {
		  ex.printStackTrace();
	  }
	  
	  
	  
  }
  /**
   *    Creating the graphical user interface for the program.
   **/
  public void createGUI() {
	
	tabbed_pane = new JTabbedPane(JTabbedPane.TOP); // the tabbed pane will be show more sheets
	tabbed_pane.addTab( "Static SQL", this.static_main_panel );  // actually only one sheet is used
	
        // the main panel for demonstration of the static SQL queries
	this.static_main_panel.setLayout( new BorderLayout() ); 
	this.input_panel.setLayout( new GridLayout(3,3) );
	this.output_panel.setLayout( new BorderLayout() );
	
	
	// the labels and input fields
	this.input_panel.add( new Label("Content:") );
	this.input_panel.add( this.name_field );
	this.input_panel.add( new Label("Search in field:") );
	this.input_panel.add( this.field_choice );
	this.input_panel.add( this.search_button );
	
	
	// adding event listeners
	this.field_choice.addItemListener(this);	
	this.search_button.addActionListener(this);
	
	this.getContentPane().add( tabbed_pane );
	this.static_main_panel.add( input_panel, BorderLayout.NORTH );
	this.static_main_panel.add( output_panel, BorderLayout.CENTER);
	
	// column names in a vector
	this.column_names_vector = new Vector();
	this.column_names_vector.add( "First name" );
	this.column_names_vector.add( "Last name" );
	this.column_names_vector.add( "Email" );
	this.column_names_vector.add( "Salary" );
	this.column_names_vector.add( "Department" );
	
	// need to use a table model for dynamic table handling
	this.table_model = new DefaultTableModel( column_names_vector, 0 );
	this.result_table = new JTable( table_model );
    this.scroll_pane = new JScrollPane(result_table);
	this.output_panel.add( scroll_pane );
	
	
	// the column names listed into a drop-down list
	this.field_choice.add( "First name" );
	this.field_choice.add( "Last name" );
	this.field_choice.add( "Email" );
	this.field_choice.add( "Department" );
	
	choice_string = "First name";
  }
	
	
  public void actionPerformed( ActionEvent e ) {
	if ( e.getSource() == this.search_button ) {
		
		/******************* Starting queries ********************/

		String sql = "";
		if ( this.name_field.getText().equals("") ) {
			
			sql = "SELECT first_name, last_name, email, salary, department_name 
                                            FROM employees, departments 
                                            WHERE employees.department_id = departments.department_id 
                                            ORDER BY last_name";
    
		} else {
			if ( choice_string == "Last name" ) {
				sql = "SELECT first_name, last_name, email, salary, department_name 
                                            FROM employees, departments 
                                            WHERE employees.department_id = departments.department_id AND 
                                                  last_name LIKE '"+ name_field.getText() +"' 
                                            ORDER BY last_name";
			} else if (choice_string == "First name") {
                                sql = "SELECT first_name, last_name, email, salary, department_name 
                                            FROM employees, departments 
                                            WHERE employees.department_id = departments.department_id AND 
                                            first_name LIKE '"+ name_field.getText() +"' 
                                            ORDER BY lasr_name";
			} else if (choice_string == "Email") {
                                sql = "SELECT first_name, last_name, email, salary, department_name 
                                            FROM employees, departments 
                                            WHERE employees.department_id = departments.department_id AND 
                                            email LIKE '"+ name_field.getText() +"' 
                                            ORDER BY last_name";
			} else if (choice_string == "Department") {
                                 sql = "SELECT first_name, last_name, email, salary, department_name 
                                            FROM employees, departments 
                                            WHERE employees.department_id = departments.department_id AND 
                                            department_name LIKE '"+ name_field.getText() +"' 
                                            ORDER BY last_name";
			}
			
		}
		
		try {
			System.out.println( sql );
			rs = stmt.executeQuery( sql );
		
			// removing all rows from the table
			int count = table_model.getRowCount();
			for ( int i = count-1; i>=0; i-- ) {
				table_model.removeRow(i);
			}
			repaint();
		
			while (rs.next()) {
				String row[] = {rs.getString(1), rs.getString(2), rs.getString(3), 
                                                rs.getInt(4) + "", rs.getString(5)};
				
				this.table_model.addRow( row ); // adding new row into the table
			}
			repaint();
		}catch ( SQLException ex ) {
			ex.printStackTrace();
		}
		
	}
  }
  
  public void itemStateChanged( ItemEvent e ) {
	  this.choice_string = field_choice.getSelectedItem();
  }
	
  /** The main method **/ 
  public static void main (String args[]) throws SQLException
  {
	
    
    
    JDBCTestGUI gui = new JDBCTestGUI( "Test application to try JDBC with Oracle" );
    
    gui.setVisible(true);
    gui.show();
    
     // this is an implementation of window listener
      // the program will be stopped if you close the main frame
      WindowListener listener = new WindowAdapter() {
        public void windowClosing(WindowEvent we) {
          System.exit(0);
        }
      };
      gui.addWindowListener(listener);
    
  }
}