coneccion.java

ejemplo de java para conexion a base de datos

/*
 * coneccion.java
 *
 * Created on 16 de junio de 2004, 11:30 PM
 */

/**
 *
 * @author  GeBuSe
 */

import java.sql .*;
import javax.swing.JOptionPane ;
public class coneccion extends javax.swing.JDialog  {  
private Connection conn; 
String nombre_clave;
String nombre_usuario;
String g;


/** Creates new form coneccion */
    
    public coneccion(java.awt.Frame parent, boolean modal){
        super(parent, modal);
        initComponents();
        this.setBounds(0, 0, 500, 400);
         String g;  
         g="jdbc:mysql://localhost/tarea";
         nombre.setText(g);
        //asegurar la coneccion....
       }
    
    public Connection recupera_coneccion(){
     return(conn);   
        }
    
    
    
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    private void initComponents() {//GEN-BEGIN:initComponents
        botonconec = new javax.swing.JButton();
        cancelar = new javax.swing.JButton();
        nombre = new javax.swing.JTextField();
        label2 = new java.awt.Label();
        usuario = new javax.swing.JTextField();
        clave = new javax.swing.JTextField();
        label4 = new java.awt.Label();
        label5 = new java.awt.Label();

        getContentPane().setLayout(null);

        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                closeDialog(evt);
            }
        });

        botonconec.setText("conectar");
        botonconec.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                botonconecActionPerformed(evt);
            }
        });

        getContentPane().add(botonconec);
        botonconec.setBounds(30, 160, 90, 30);

        cancelar.setText("cancelar");
        cancelar.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                cancelarActionPerformed(evt);
            }
        });

        getContentPane().add(cancelar);
        cancelar.setBounds(160, 160, 100, 30);

        nombre.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                nombreActionPerformed(evt);
            }
        });

        getContentPane().add(nombre);
        nombre.setBounds(10, 30, 210, 20);

        label2.setText("datos de la base de datos");
        getContentPane().add(label2);
        label2.setBounds(240, 30, 130, 20);

        getContentPane().add(usuario);
        usuario.setBounds(20, 100, 90, 20);

        clave.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                claveActionPerformed(evt);
            }
        });

        getContentPane().add(clave);
        clave.setBounds(20, 130, 90, 20);

        label4.setText("nombre de usuario");
        getContentPane().add(label4);
        label4.setBounds(250, 100, 120, 20);

        label5.setText("clave");
        getContentPane().add(label5);
        label5.setBounds(250, 130, 70, 20);

        pack();
    }//GEN-END:initComponents

    private void nombreActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_nombreActionPerformed
        // Add your handling code here:
    }//GEN-LAST:event_nombreActionPerformed

    private void claveActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_claveActionPerformed
        // Add your handling code here:
    }//GEN-LAST:event_claveActionPerformed

    private void cancelarActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_cancelarActionPerformed
dispose();        // Add your handling code here:
    }//GEN-LAST:event_cancelarActionPerformed

    private void botonconecActionPerformed(java.awt.event.ActionEvent evt) {//GEN-FIRST:event_botonconecActionPerformed
 try{   


      nombre_usuario=usuario.getText(); 
      nombre_clave=clave.getText();
      g=nombre.getText();
      cargaDriver(); 
      conectar();
      dispose();
 }
 catch(Exception e){}

      
    }//GEN-LAST:event_botonconecActionPerformed
    /** Closes the dialog */
    private void closeDialog(java.awt.event.WindowEvent evt) {//GEN-FIRST:event_closeDialog
       setVisible(false);
        dispose();
    }//GEN-LAST:event_closeDialog
    
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        new coneccion(new javax.swing.JFrame(), true).show();
    }
public void cargaDriver() throws Exception
    {
        try
        {
            Class.forName("com.mysql.jdbc.Driver").newInstance(); 
            System.out.println("Creada Instancia");
        }
        catch (Exception ex)
        { 
           JOptionPane.showMessageDialog(null, "Error en la coneccion");
        }
    }
    
    public void conectar() throws Exception
    {
        try
        {
       
            
         conn = DriverManager.getConnection(g,nombre_usuario,nombre_clave);
         JOptionPane.showMessageDialog(null, "Conectado");
        }
        catch (SQLException ex)
        {
            System.out.println("SQLException: " + ex.getMessage()); 
            System.out.println("SQLState: " + ex.getSQLState()); 
            System.out.println("VendorError: " + ex.getErrorCode()); 
        }

    }
 
    
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JButton botonconec;
    private javax.swing.JButton cancelar;
    private javax.swing.JTextField clave;
    private java.awt.Label label2;
    private java.awt.Label label4;
    private java.awt.Label label5;
    private javax.swing.JTextField nombre;
    private javax.swing.JTextField usuario;
    // End of variables declaration//GEN-END:variables
    
}