Thread: a big question

a big question

From

Dam Avalos

Date:

21 May 2004, 05:03:44

Hi!

I have a big problem with the postgress driver, and i hope you can help me, i�m programming with java, and java has a method name Class.forName() that ask for the postgress driver... I send you the archive ConexionBD.java, and i hope you can help me, because when i run the program it says that it can�t get the driver, or found the driver, or something like that, so, well if you can help me i�ll be very gratefull with you, thanks a lot

/*
ARCHIVO: ConexionBD.java
AUTOR: Daniela Avalos Monroy
aleidam8@yahoo.com
Programa que hace una conexion a Base de Datos
realizada en postgress por medio de codigo en
Java*/

package libro.src;

import java.sql.*;
import java.net.URL;

public class ConexionBD
{
    //Los datos de configuracion
    static String URL = "jdbc:postgresql://ada.fciencias.unam.mx/libroo";//Nombre de la base de datos.
    static String USER = "davalosm";
    static String PASSWD = "";

Connection con = null;
Statement stmt=null;

public ConexionBD()
{}

    /**Esta funcion establece una conexion a la BD.*/
    public void openConexion()
        {

            System.out.println(" Estableciendo conexion...");
            try
     {
  //Class.forName("postgresql.Driver"); //Cualquiera de los 2 funciona.
  Class.forName("org.postgresql.Driver"); //Cualquiera de los 2 funciona.
     }
            catch(Exception e)
     {
  System.out.println("No se puede cargar el driver de psql.");
     }

System.out.println("Driver de psql cargado con exito...!!!.");

            try
            {
                con = DriverManager.getConnection(URL, USER, PASSWD);
                System.out.println("Conexion establecida...");
     }
            catch( Exception e)
     {
  e.printStackTrace();
     }
        }


    /*Esta funcion cierra la conexion*/
    public void closeConexion()
        {
            try
     {
  con.close();
  System.out.println("Conexion cerrada...");
     }
            catch( Exception e)
     {
  e.printStackTrace();
  System.out.println("Error al cerrar la conexion...");
     }
        }

    /*Esta funcion cierra la conexion*/
    public void closeStatement()
        {
            try
     {
  stmt.close();
  System.out.println("Statement cerrado...");
     }
            catch( Exception e)
     {
  e.printStackTrace();
  System.out.println("Error al cerrar el statement...");
     }
        }

    /**Esta funcion nos permite ejecutar una consulta de tipo Update*/
    public void executeUpdate(String _Update)
        {
            try
     {
  stmt = con.createStatement();
  System.out.println("Creamos el statement...");
  stmt.executeUpdate(_Update);
  System.out.println("Executamos el update...");
  //stmt.close();
          System.out.println("Cerramos el statement...");
     }
            catch( Exception e)
     {
  e.printStackTrace();
  System.out.println("Error al cerrar el statement...");
                closeStatement();
                closeConexion();
     }
        }

    /** Eejecuta una consulta */
    public ResultSet executeQuery(String _Query)
        {
            ResultSet rs = null;
            Statement stmt;
            try{

                stmt = con.createStatement();
                System.out.println("Creamos el statement...");
                rs = stmt.executeQuery(_Query);
                System.out.println("Executamos el Query...y almacenamos en el ResutlSet");
                //stmt.close();
                System.out.println("Cerramos el statement...");

            }
            catch( Exception e)
            {
                e.printStackTrace();
                System.out.println("Error al cerrar el statement...");
                closeStatement();
                closeConexion();
     }
            return rs;
        }
}

/*Fin de archivo ConexionBD.java*/

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Re: a big question

From

Oliver Jowett

Date:

21 May 2004, 07:58:32

Dam Avalos wrote:
> Hi!
> I have a big problem with the postgress driver, and i hope you can help
> me, i´m programming with java, and java has a method name
> Class.forName() that ask for the postgress driver... I send you the
> archive ConexionBD.java, and i hope you can help me, because when i run
> the program it says that it can´t get the driver, or found the driver,
> or something like that, so, well if you can help me i´ll be very
> gratefull with you, thanks a lot

Without more detail it's hard to be sure, but the most likely problem is
that the PostgreSQL JDBC driver is not in your classpath. See
http://www.postgresql.org/docs/7.4/static/jdbc.html#JDBC-CLASSPATH

-O