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();

}

}

Marcelo,

Just type

java TestPostreSQL

to run it

Dave
On Wed, 2003-01-15 at 08:08, Marcelo Pereira wrote:

Hi Jeffrey,

Thanks for your example code. I have compiled it without any problem, but
when I try to run I have the following:

$ javac TestPostgreSQL.java
$ java TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

$ java -classpath
/usr/local/pgsql/share/java/postgresql.jar:. TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

$ export CLASSPATH=/usr/local/pgsql/share/java/postgresql.jar:.
$ java TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

As you can see I have this problem, whatever I try to do. So I thought my
JDBC driver wasn't properly compiled, so I have downloaded the 7.3 JDBC
driver from PostgreSQL.org (pg73jdbc1.jar) and run all the tests above,
always with the same problem.

What am I doing wrong??

Thanks in advance and
Best Regards,

Marcelo Pereira

-- Remember that only God and ^[:w saves.
__
(_.\ � Marcelo Pereira |
/ / ___ marcelo@pereira.com |
/ (_/ _ \__ [Math|99]-IMECC |
_______\____/_\___)___Unicamp_______________/

--- Jeffrey Melloy, with his fast fingers, wrote:

:> 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();
:>
:> }
:>
:>
:> }
:>
:>
:>
:>
:>
:>
:> ---------------------------(end of broadcast)---------------------------
:> TIP 6: Have you searched our list archives?
:>
:> http://archives.postgresql.org
:>

---------------------------(end of broadcast)---------------------------
TIP 6: Have you searched our list archives?

http://archives.postgresql.org

--
Dave Cramer <Dave@micro-automation.net>

Hi Jeffrey,

Thanks for your example code. I have compiled it without any problem, but
when I try to run I have the following:

$ javac TestPostgreSQL.java
$ java TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

$ java -classpath
/usr/local/pgsql/share/java/postgresql.jar:. TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

$ export CLASSPATH=/usr/local/pgsql/share/java/postgresql.jar:.
$ java TestPostgreSQL.class
Exception in thread
"main" java.lang.NoClassDefFoundError: TestPostgreSQL/class

As you can see I have this problem, whatever I try to do. So I thought my
JDBC driver wasn't properly compiled, so I have downloaded the 7.3 JDBC
driver from PostgreSQL.org (pg73jdbc1.jar) and run all the tests above,
always with the same problem.

What am I doing wrong??

Thanks in advance and
Best Regards,

Marcelo Pereira

-- Remember that only God and ^[:w saves.
__
(_.\ � Marcelo Pereira |
/ / ___ marcelo@pereira.com |
/ (_/ _ \__ [Math|99]-IMECC |
_______\____/_\___)___Unicamp_______________/

--- Jeffrey Melloy, with his fast fingers, wrote:

:> 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();
:>
:> }
:>
:>
:> }
:>
:>
:>
:>
:>
:>
:> ---------------------------(end of broadcast)---------------------------
:> TIP 6: Have you searched our list archives?
:>
:> http://archives.postgresql.org
:>

Hi Jeffrey, Dave and All,

Thanks for your answer, I got it running!

Thanks and Best Regards,

Marcelo Pereira

-- Remember that only God and ^[:w saves.
__
(_.\ � Marcelo Pereira |
/ / ___ marcelo@pereira.com |
/ (_/ _ \__ [Math|99]-IMECC |
_______\____/_\___)___Unicamp_______________/

--- Dave Cramer, with his fast fingers, wrote:

:> Marcelo,
:>
:> Just type
:>
:> java TestPostreSQL
:>
:> to run it
:>
:> Dave
:> On Wed, 2003-01-15 at 08:08, Marcelo Pereira wrote:
:> > Hi Jeffrey,
:> >
:> > Thanks for your example code. I have compiled it without any problem, but
:> > when I try to run I have the following:
:> >
:> > $ javac TestPostgreSQL.java
:> > $ java TestPostgreSQL.class
:> > Exception in thread
:> > "main" java.lang.NoClassDefFoundError: TestPostgreSQL/class
:> >
:> > $ java -classpath
:> > /usr/local/pgsql/share/java/postgresql.jar:. TestPostgreSQL.class
:> > Exception in thread
:> > "main" java.lang.NoClassDefFoundError: TestPostgreSQL/class
:> >
:> > $ export CLASSPATH=/usr/local/pgsql/share/java/postgresql.jar:.
:> > $ java TestPostgreSQL.class
:> > Exception in thread
:> > "main" java.lang.NoClassDefFoundError: TestPostgreSQL/class
:> >
:> > As you can see I have this problem, whatever I try to do. So I thought my
:> > JDBC driver wasn't properly compiled, so I have downloaded the 7.3 JDBC
:> > driver from PostgreSQL.org (pg73jdbc1.jar) and run all the tests above,
:> > always with the same problem.
:> >
:> > What am I doing wrong??
:> >
:> > Thanks in advance and
:> > Best Regards,
:> >
:> > Marcelo Pereira
:> >
:> > -- Remember that only God and ^[:w saves.
:> > __
:> > (_.\ � Marcelo Pereira |
:> > / / ___ marcelo@pereira.com |
:> > / (_/ _ \__ [Math|99]-IMECC |
:> > _______\____/_\___)___Unicamp_______________/
:> >
:> > --- Jeffrey Melloy, with his fast fingers, wrote:
:> >
:> > :> 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();
:> > :>
:> > :> }
:> > :>
:> > :>
:> > :> }
:> > :>
:> > :>
:> > :>
:> > :>
:> > :>
:> > :>
:> > :> ---------------------------(end of broadcast)---------------------------
:> > :> TIP 6: Have you searched our list archives?
:> > :>
:> > :> http://archives.postgresql.org
:> > :>
:> >
:> >
:> > ---------------------------(end of broadcast)---------------------------
:> > TIP 6: Have you searched our list archives?
:> >
:> > http://archives.postgresql.org
:> --
:> Dave Cramer <Dave@micro-automation.net>
:>
:>
:> ---------------------------(end of broadcast)---------------------------
:> TIP 2: you can get off all lists at once with the unregister command
:> (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
:>