Re: Connection Problem with JDBC

I'm sorry- I didn't look closely enough at the code you placed in your
original post. (I should have wondered why there were so many exceptions to
catch.)

I'd suggest replacing this chunk of code:

            Driver driver = (Driver)
                Class.forName("org.postgresql.Driver").newInstance();
            DriverManager.registerDriver(driver);

with this:

            Class.forName("org.postgresql.Driver");


Then you can also eliminate the two exception handlers that you just added.

I think all of the other code that you have in that section is only
necessary if you're loading the driver after passing it as a parameter to
the jvm.

-NickF





> -----Original Message-----
> From: Steven Murphy [mailto:stevenmurphy@hotmail.com]
> Sent: Monday, February 25, 2002 9:58 AM
> To: nickf@ontko.com; pgsql-jdbc@postgresql.org
> Subject: RE: [JDBC] Connection Problem with JDBC
>
>
> I have added the extra handlers to the catch SQL exception part
> of the code,
> but when I compiled the program I got the following error :-
>
> ConnectDemo.java:19: unreported exception
> java.lang.IllegalAccessException;
> must be caught or declared to be thrown
>             Class.forName("org.postgresql.Driver").newInstance();
>                              ^
> 1 error
>
> Below is the code that I added :-
>
>        } catch (SQLException se) {
>           System.err.println( se.getMessage() );
>        } catch (ClassNotFoundException cnfe) {
>           System.err.println( cnfe.getMessage() );
>        } catch (InstantiationException ie) {
>           System.err.println( ie.getMessage() );
>           System.exit(-1);
>        }
>
> Do you know what might be causing this error?
>
> Cheers
> Steve.
>
> ---------------------------------------------------------------
>
> From: "Nick Fankhauser" <nickf@ontko.com>
> Reply-To: <nickf@ontko.com>
> To: "Steven Murphy" <stevenmurphy@hotmail.com>,
> <pgsql-jdbc@postgresql.org>
> Subject: RE: [JDBC] Connection Problem with JDBC
> Date: Mon, 25 Feb 2002 09:04:22 -0500
>
>
> In the place where you catch the SQL exception, you just need to add a
> couple more exception handlers, so it would look like this:
>
>        } catch (SQLException se) {
>            System.err.println( se.getMessage() );
>        } catch (ClassNotFoundException cnfe) {
>            System.err.println( cnfe.getMessage() );
>        } catch (InstantiationException ie) {
>            System.err.println( ie.getMessage() );
>
> Then try to compile again.
>
> -NickF
>
>  > -----Original Message-----
>  > From: Steven Murphy [mailto:stevenmurphy@hotmail.com]
>  > Sent: Monday, February 25, 2002 9:02 AM
>  > To: nickf@ontko.com; pgsql-jdbc@postgresql.org
>  > Subject: Re: [JDBC] Connection Problem with JDBC
>  >
>  >
>  > Hi all,
>  >
>  > I have added the code to load the drivers using Class.forName in
>  > main, but
>  > when I compile the code I get the following errors :-
>  >
>  > ConnectDemo.java:27: unreported exception
>  > java.lang.ClassNotFoundException;
>  > must be caught or declared to be thrown
>  >             Class.forName("org.postgresql.Driver").newInstance();
>  >                      ^
>  > ConnectDemo.java:27: unreported exception
>  > java.lang.InstantiationException;
>  > must be caught or declared to be thrown
>  >             Class.forName("org.postgresql.Driver").newInstance();
>  >                              ^
>  > 2 errors
>  >
>  > Here is how the program looks now I have added the Class.forName bit :-
>  >
>  > // Import the JDBC classes.
>  > //
>  > import java.sql.*;
>  >
>  > public class ConnectDemo {
>  >
>  >   public static void main(String[] argv) {
>  >
>  >       if (argv.length < 3) {
>  >           usage();
>  >       }
>  >       String url  = argv[0];
>  >       String user = argv[1];
>  >       String pass = argv[2];
>  >
>  >       // Invoke getConnection() to create the
>  >       // connection object.
>  >       //
>  >       Connection conn;
>  >       try {
>  >             Driver driver = (Driver)
>  >                 Class.forName("org.postgresql.Driver").newInstance();
>  >             DriverManager.registerDriver(driver);
>  >           conn = DriverManager.getConnection(url, user, pass);
>  >           System.out.println("Connection successful.");
>  >           System.out.println("Connection as String: " + conn);
>  >       } catch (SQLException e) {
>  >           System.err.println( e.getMessage() );
>  >           System.exit(-1);
>  >       }
>  >
>  >   }
>  >
>  >   static void usage() {
>  >
>  >       System.err.println("Usage:");
>  >       System.err.print("java -Djdbc.drivers=DRIVERCLASS PROGRAM ");
>  >       System.err.println("URL USER PASS");
>  >       System.exit(-1);
>  >
>  >   }
>  >
>  > Do I need to import some other things to get this to work?
>  > Sorry I'm a bit of a novice with all of this.
>  >
>  > Cheers
>  > Steve.
>  >
>  > --------------------------------------------------------------------
>  >
>  > From: "Nick Fankhauser" <nickf@ontko.com>
>  > Reply-To: <nickf@ontko.com>
>  > To: "Steven Murphy" <stevenmurphy@hotmail.com>,
>  > <pgsql-jdbc@postgresql.org>
>  > Subject: Re: [JDBC] Connection Problem with JDBC
>  > Date: Mon, 11 Feb 2002 15:44:04 -0500
>  >
>  >  > The command I am using to run the program is
>  >  > java -Djdbc.drivers=org.postgresql.Driver ConnectDemo
>  >  > jdbc:postgresql:javatest postgres ' '
>  >
>  > I think if it was a classpath problem, you'd be getting a
>  > "ClassNotFoundException" I believe the "No Suitable Driver"
>  > indicates that
>  > among the drivers you have loaded, none matches the database url
>  > passed to
>  > DriverManager.getConnection. ...But the command & url above look
>  > just fine &
>  > I can't see any opportunity in your program for the url to get mangled.
>  >
>  > Have you tried loading the drivers using Class.forName in main?
>  > I'm not sure
>  > what it would tell us if it worked, but if it didn't work that
>  > way, I think
>  > I'd download the driver again.
>  >
>  > -Nick
>  >
>  >
> --------------------------------------------------------------------------
>  > Nick Fankhauser  nickf@ontko.com  Phone 1.765.935.4283  Fax
> 1.765.962.9788
>  > Ray Ontko & Co.     Software Consulting Services
> http://www.ontko.com/
>  >
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