[CLUE-Tech] Java, PostgreSQL and JDBC help needed

Jeffery Cann fabian at jefferycann.com
Thu Jun 5 22:20:08 MDT 2003


Since you didn't tell us which class was not found, it's hard to say if your 
problem is your CLASSPATH or not.

Post the command line that you are using to run your program.  My guess is 
that since you have this PostgreSQLtest class in package JDBCTest, you forgot 
to do this:

$ java JDBCTest.PostgreSQLTest

Also, make sure your path to this package is in your CLASSPATH.  A simpler 
approach is to gid rid of the package statement in your .java file and then 
do:

$ java PostgreSQLTest

Jeff

On Thursday 05 June 2003 10:02 pm, Joseph Thomas wrote:
> Hello,
>
> I need some help here. I am a student and dont know alot about Linux yet. I
> am trying to be able to program in Java in linux.
> I am running Red Hat 9, PostgreSQL 7.3.2
> I have the J2SDK 1.3.1 installed and working.
> I have set up a database in PostgreSQL and am able to run queries on it.
> The trouble I am having is that I cannot get my program to connect to the
> DB, I am recieving a Class not found exception.
> I have the .jar for pgsql in my CLASSPATH set in my $HOME/.bash_profile and
> it seems to be working.
> Here is my code I am using:
>
> package JDBCTest;
> import java.sql.*;
>
> class PostgreSQLTest
> {
>   public static void main (String[] args)
>   {
> 	try
> 	{
> 	  Driver driver = (Driver)
> 		Class.forName("postgresql.Driver").newInstance();
>
> 	  DriverManager.registerDriver(driver);
>
> 	  String     url = "jdbc:postgresql:javatest";
> 	  Connection con = DriverManager.getConnection(url, "postgres", "");
> 	  Statement  stm = con.createStatement();
>
> 	  stm.setQueryTimeout(10);
> 	  ResultSet  rs  = stm.executeQuery("select col1 from test");
>
> 	  rs.next();
>
> 	  System.out.println(rs.getString(1));
>
> 	} catch (SQLException e) {
>
> 	  System.out.println("Exception!");
> 	  System.out.println(e.toString());
> 	}catch (ClassNotFoundException e) {
>
> 		  System.out.println("Exception!");
> 		  System.out.println(e.toString());
> 	}catch (InstantiationException e) {
>
> 			  System.out.println("Exception!");
> 			  System.out.println(e.toString());
> 	}	catch (IllegalAccessException e) {
>
> 			  System.out.println("Exception!");
> 			  System.out.println(e.toString());
> 	}
>   }//main()
> } //class
>
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