Re: jdbc connection

----- 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