Still baffled by a CONNECTion problem

From: "Peter Cook" <ttpcook(at)hotmail(dot)com>
To: pgsql-jdbc(at)postgresql(dot)org
Subject: Still baffled by a CONNECTion problem
Date: 2005-10-08 07:34:39
Message-ID: BAY103-F31AFB9DF052576CD5CE9BEB7870@phx.gbl
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It appears my first appeal for help wasnt clear enough.

I want to connect my Java Application running on Windows 2000 to my
postgresql database.

From what I understand and have read there are AT LEAST 2 things I need to
do.

(1) Have the application load the relevant JDBC driver and

(2) Make a connection.

With respect to (1), despite numerous attempts I have been unable to resolve
the ClassNotFound exception.

I have set the CLASSPATH environment variable as follows:
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;C:\PROGRA~1\ULTRAE~1;C:\Program
Files\Java\jdk1.5.0_04\bin;C:\Program Files\PostgreSQL\8.0\jdbc

I have written some test code in Java to load the Driver, as follows:
public void displayClasspath()
{
String driverPath = "C:\\Program Files\\PostgreSQL\\8.0\\jdbc";
String classpath = System.getProperty("java.class.path");
_displayTextArea.append("Classpath = " + classpath + "\n");

classpath = classpath + ";" + driverPath +
"\\postgresql-8.0-311.jdbc3.jar";
System.setProperty("java.class.path", classpath);
_displayTextArea.append("Classpath = " + classpath + "\n");

System.setProperty("jdbc.drivers", driverPath);
String drivers = System.getProperty("jdbc.drivers");
_displayTextArea.append("Drivers = " + drivers + "\n");

// 1. Load the jdbc.odbc database driver class
try
{
File driverDir = new File(driverPath);
if ( driverDir.isDirectory() )
_displayTextArea.append("DriverDir is a directory \n");
else
_displayTextArea.append("DriverDir is NOT a directory \n");

File dFile = new File(driverPath +
"\\org\\postgresql\\Driver.class");
if ( dFile.isFile() )
_displayTextArea.append("Driver is a file \n");
else
_displayTextArea.append("Driver is NOT a file \n");

String driver = "org.postgresql.Driver";
driverPath = driverPath + "\\" + driver;

Class.forName(driver);
}
catch (ClassNotFoundException cnfe)
{
System.out.println("ClassNotFoundException.");
}
}

The output from this code is as follows:
Classpath = C:\Eclipse\Workspace\Test
Classpath = C:\Eclipse\Workspace\Test;C:\Program
Files\PostgreSQL\8.0\jdbc\postgresql-8.0-311.jdbc3.jar
Drivers = C:\Program Files\PostgreSQL\8.0\jdbc
DriverDir is a directory
Driver is a file

So:
- for some unknown reason my Eclipse editor has reset my CLASSPATH
- but despite this I am able to programmatically adjust the CLASSPATH
property to suit
- Java recognized the directory where I have installed the JAR file as a
valid directory and is able to locate the relevant driver file

WHY WONT IT LOAD the DRIVER?????

With respect to (2) creating a connection.
From what I have read I need to set the PostMaster to run with a -I flag
to enable TCP/IP communication.
However the Postmaster is started somewhere in the boot sequence, and I
dont know how to adjust its startup.

HOW DO I DO THIS?

IS THERE SOMETHING ELSE I NEED TO DO???

I think I can work out the connection parameters and make the connection IF
I CAN RESOLVE THESE QUESTIONS.

Yours Sincerely

Peter Cook

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