Thread: jdbc connection

jdbc connection

From

"michel verplancke"

Date:

23 January 2003, 18:49:57

Please can you help me

I try to connect a java application from a windows W2K to a Linux postgresql with a very simple query, which is "select * from table".

The error message is "connection is closed, operation is not permitted"

here is the class definition

import java.sql.*;

public class JdbcQuery {
    private Connection con = null;
    public int recordnb = 0;
    private Statement stmt = null;
    private ResultSet result = null;

    private String driver = "org.postgresql.Driver";
    private String url = "jdbc:postgresql://COMPUTERNAME:5432/DATABASE";
    private String username = "michels";
    private String password = "";

boolean ConnectPostgresql(String Valquery) {
try   // Attempt to load the JDBC driver
    {
     Class.forName(driver);
     }
    catch( Exception e ) // error
    {
  JOptionPane.showMessageDialog(null, "Failed to load the following JDBC driver : " + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
     }
    try
    {
  con = DriverManager.getConnection ( url, username, password);
  stmt = con.createStatement();
    }
   catch ( Exception e)
    {
   JOptionPane.showMessageDialog(null, "Problems connecting to " + url + ":" + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
   }
     if( con != null)
      {
        try { con.close(); }
        catch( Exception e2 ) {}
     }
   try
    {
  result = stmt.executeQuery(Valquery);           IT's HERE THAT I GET THE PROBLEM !!!!!!!
    }
    catch (Exception e)
  {
   JOptionPane.showMessageDialog(null, "Problems with resultset : " + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
  }
return true;
  }

int GetRecordnb()
{
    try
    {
  result.last();
  recordnb = result.getRow();
  result.beforeFirst();

    } // end try
   catch ( Exception e)
    {
        System.err.println( "problems in GetRecordnb managing resultset" );
        System.err.println( e.getMessage() );
     if( con != null)
      {
        try { con.close(); }
        catch( Exception e2 ) {}
     }
    } // end catch
  return recordnb;
}

// alternative (donne le même résultat que la manière précédente)

// System.out.println(result.getFetchSize());

ResultSet GetRecordData()
{
return result;
}

void CloseConnection()
{
  try { stmt.close(); }
        catch( Exception e ) {}
        try { con.close(); }
        catch( Exception e ) {}
      }

} // end class

If I try the same query from the Cygwin psql it works !!

Does somebody have an idea ?

Thanks

michel.verplancke@wanadoo.be

Re: jdbc connection

From

"Mykola Dudar"

Date:

29 January 2003, 03:34:48

Thats my code - works perfectly on WXP.

import java.sql.*;

public class tst_jdbc
{
public static void start ()
       throws SQLException
{
    // Load the JDBC driver
    DriverManager.registerDriver(new org.postgresql.Driver());

    String url = "jdbc:postgresql://COMPUTERNAME/DATABASENAME";
    String userName = "USERNAME";
    String password = "PASSWORD";

Connection conn =
DriverManager.getConnection (url, userName, password);

// Create a Statement
Statement stmt = conn.createStatement ();

// Select the all rows

ResultSet rset = stmt.executeQuery ("select * from TABLENAME");

    while (rset.next ())
      System.out.println (rset.getString (1));
} // start();
public static void main (String args [])
       throws SQLException
{
    start ();
}
}

----- Original Message -----
From: michel verplancke
To: pgsql-jdbc@postgresql.org
Sent: Sunday, January 19, 2003 12:03 PM
Subject: [JDBC] jdbc connection

Please can you help me

I try to connect a java application from a windows W2K to a Linux postgresql with a very simple query, which is "select * from table".

The error message is "connection is closed, operation is not permitted"

here is the class definition

import java.sql.*;

public class JdbcQuery {
    private Connection con = null;
    public int recordnb = 0;
    private Statement stmt = null;
    private ResultSet result = null;

    private String driver = "org.postgresql.Driver";
    private String url = "jdbc:postgresql://COMPUTERNAME:5432/DATABASE";
    private String username = "michels";
    private String password = "";

boolean ConnectPostgresql(String Valquery) {
try   // Attempt to load the JDBC driver
    {
     Class.forName(driver);
     }
    catch( Exception e ) // error
    {
  JOptionPane.showMessageDialog(null, "Failed to load the following JDBC driver : " + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
     }
    try
    {
  con = DriverManager.getConnection ( url, username, password);
  stmt = con.createStatement();
    }
   catch ( Exception e)
    {
   JOptionPane.showMessageDialog(null, "Problems connecting to " + url + ":" + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
   }
     if( con != null)
      {
        try { con.close(); }
        catch( Exception e2 ) {}
     }
   try
    {
  result = stmt.executeQuery(Valquery);           IT's HERE THAT I GET THE PROBLEM !!!!!!!
    }
    catch (Exception e)
  {
   JOptionPane.showMessageDialog(null, "Problems with resultset : " + e.getMessage(), "Error ! ", JOptionPane.PLAIN_MESSAGE);
  return false;
  }
return true;
  }

int GetRecordnb()
{
    try
    {
  result.last();
  recordnb = result.getRow();
  result.beforeFirst();

    } // end try
   catch ( Exception e)
    {
        System.err.println( "problems in GetRecordnb managing resultset" );
        System.err.println( e.getMessage() );
     if( con != null)
      {
        try { con.close(); }
        catch( Exception e2 ) {}
     }
    } // end catch
  return recordnb;
}

// alternative (donne le même résultat que la manière précédente)

// System.out.println(result.getFetchSize());

ResultSet GetRecordData()
{
return result;
}

void CloseConnection()
{
  try { stmt.close(); }
        catch( Exception e ) {}
        try { con.close(); }
        catch( Exception e ) {}
      }

} // end class

If I try the same query from the Cygwin psql it works !!

Does somebody have an idea ?

Thanks

michel.verplancke@wanadoo.be