Re: JDBC

Marcelo Pereira wrote:

>Would you send to me a really simple example java source code using jdbc,
>acessing a simple table at PostgreSQL
>

Giving credit where credit is due, this is Mark Liyanage's simple java
program, from www.entorpy.ch. It was written for OS X, but there
shouldn't be a problem.

/*
* TestPostgreSQL.java
*
*
* History:
*
* When Who What
* ==============================================================================
* 2001-06-23 Marc Liyanage First version
*
*
* License:
*
* Copyright abandoned 2001 by Marc Liyanage
* Do with this whatever you want.
*
*/

import java.sql.*;

/**
* The TestPostgreSQL class shows how to access the PostgreSQL
* DB server on Mac OS X using the JDBC interface.
* It assumes the installation has been performed according
* to the instructions at http://www.entropy.ch/software/macosx/postgresql.
*
*
* You compile it like this:
*
* % javac TestPostgreSQL.java
*
* Make sure that the PostgreSQL server has been
* started with the -i flag. This is not the case in
* the example lines of the installation instructions mentioned
* above and in the StartupItem package that's available
* from the same location. The -i flag tells the DB server
* to listen for connection requests from the network
* and I have left it off by default for security reasons.
*
* If the server is running correctly (with -i), run the Test like this:
* (in the same directory where you compiled the example)
*
* % java -classpath /usr/local/pgsql/share/java/postgresql.jar:. TestPostgreSQL
*
* You should see the current date as returned by the DB server:
*
* 2001-06-23 16:31:49+02
*
*
* @author Marc Liyanage
* @version 1.0
*/
public class TestPostgreSQL {

public static void main(String argv[]) throws Exception {

// Load the driver class
//
Class.forName("org.postgresql.Driver");

// Try to connect to the DB server.
// We tell JDBC to use the "postgresql" driver
// and to connect to the "template1" database
// which should always exist in PostgreSQL.
// We use the username "postgres" and no
// password to connect. Since we're not accessing
// any tables but only an SQL function
// this should work.
//
Connection conn = DriverManager.getConnection(
"jdbc:postgresql:template1",
"postgres",
""
);

// Set up and run a query that fetches
// the current date using the "now()" PostgreSQL function.
//
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("SELECT now();");

// Iterate through the rows of the result set
// (obviously only one row in this example) and
// print each one.
//
while (rset.next()) {
System.out.println(rset.getString(1));
}

// Close result set, statement and DB connection
//
rset.close();
stmt.close();
conn.close();

}

}