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From "Wagoner, Mark" <MWago...@wildflavors.com>
Subject RE: DB2 and servlet ??? Help !!!
Date Thu, 01 Aug 2002 18:02:02 GMT
I think you are attempting to output the value if there is nothing in the
result set.

> if(!rs.next())

The .next() method will return true if it was able to fetch a row.  You are
saying, "if there is no row then..."

-----Original Message-----
From: Nishant_Awasthi@progressive.com
[mailto:Nishant_Awasthi@progressive.com]
Sent: Thursday, August 01, 2002 1:57 PM
To: Tomcat Users List
Subject: RE: DB2 and servlet ??? Help !!!



Hello John

"firstnme" is the correct column name...
What bugs me is if you see my servlet code which I am again attaching...
I try to put try and ctach every where possible so that
I can at least printStackTrace() .
But to my surprise...I am not getting any exception...or stack trace...
instead I am getting simple HTML output ...
I am attaching what
1. I see in browser
2. servlet code

 BROWSER OUTPUT
-------------------------------
paramater passed is 012


Count is0
Found the JDBC driver

Driver is properly loaded and registered
Connection URL is good
Retrieve some data from the database...
Received results:

Count is0
God Please help

--------------SERVLET CODE-------------
import java.sql.*;
import java.lang.*;
import java.io.*;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;


public class Ndb2Websphere extends HttpServlet {

      Statement stmt;
                ResultSet rs;
               int count =0;

    public void doGet (HttpServletRequest req, HttpServletResponse res)
     throws ServletException, IOException
    {


              res.setContentType("text/html");

     ServletOutputStream out = res.getOutputStream();

             String emp = req.getParameter("empnumber");
             out.println("paramater passed is "+emp +" <BR>");
                  out.println("<BR><BR>Count is"+ count);
                 try{
          Class.forName("COM.ibm.db2.jdbc.net.DB2Driver");
           out.println("<BR>Found the JDBC driver <BR>");
                     }
                     catch( Exception e)
                     {
          //        e.printStackTrace();
                            out.println("\nDriver class not found
exception");
             }
                     finally
                      {
                           out.println("<BR>Driver is properly loaded and
registered ");
                      }

               try{
                Connection con = null;


                           String url;

                       out.println("<BR>Connection URL is  good");


                        try{
                   con = DriverManager.getConnection
("jdbc:db2://10.3.13.34/SAMPLE","db2admin","db2pwd");
                        }
                        catch( Exception e4)
                        {
                                   e4.getMessage();
                e4.printStackTrace();
                        }


              // retrieve data from the database

                           out.println("<BR>Retrieve some data from the
database...");

                        try{
                stmt = con.createStatement();
                                rs = stmt.executeQuery("SELECT empno from
db2admin.employee");
          }
                         catch( Exception e5)
                         {
                                       e5.getMessage();
                e5.printStackTrace();
                         }

                   out.println("<BR>Received results:");

                         try{
                                 if(!rs.next())
                                   {
                                                   count = count +1;
                                     String a = rs.getString(1);

                           out.println(" empno is " + a );
                    out.println("<BR><BR>While Count is"+ count);
                   }
           }
                           catch( Exception e6)
                           {
                                   e6.printStackTrace();
                           }
                           out.println("<BR><BR>Count is"+ count);

               rs.close();
                       stmt.close();
                            con.close();

                }
                catch (SQLException e1)
                {
                       e1.getMessage();
                       e1.printStackTrace();
                }
                catch( Exception e)
                {
                       e.getMessage();
               e.printStackTrace();
                }
                finally
                {
                        out.println("<BR>God Please help");
                }
      }
    public void doPost (HttpServletRequest req, HttpServletResponse res)
    throws ServletException, IOException
    {
        doGet(req,res);
    }


}
----------------------------------------------------------------------------
--------

Nishant Awasthi






 

                    "Turner,

                    John"                To:     'Tomcat Users List'

                    <JTurner@AAS.        <tomcat-user@jakarta.apache.org>

                    com>                 cc:     (bcc: Nishant Awasthi)

                                         Subject:     RE: DB2 and servlet
??? Help !!!     
                    08/01/2002

                    01:50 PM

                    Please

                    respond to

                    "Tomcat Users

                    List"

 

 







Is "firstnme" the name of your column?  Or should it be "firstname"?  If
that's an error, there should be a SQLException thrown, but I don't know
the
behavior fo DB2...it may just be that you get null back.  In any case,
besides printing a stack trace, I would output something to the browser on
a
SQLException just so you can see what's going on.

John Turner
jturner@NOSPAM.aas.com

-----Original Message-----
From: Nishant_Awasthi@progressive.com
[mailto:Nishant_Awasthi@progressive.com]
Sent: Thursday, August 01, 2002 1:47 PM
To: soap-user@xml.apache.org; tomcat-user@jakarta.apache.org;
tomcat-dev@jakarta.apache.org
Subject: DB2 and servlet ??? Help !!!


Hello everyone...

I am trying to connect the run a simple servlet to retrieve the
query results from DB2 database.

1. Before writing a servlet, I wrote a simple java file and was successful
in retrieving the
contents from DB2 UDB.

2. Then I just converted the same JAVA file into servlet by adding Servlet
API and syntax in it.
3. It compiles fine.
4. Then from a web page I try to pass one parameter to my servlet.
5. The servlet doesnot retrieve any records from the database which
initially it was bringing
    when I wrote simple java file.

Code of my servlet is as:
----------------------
import java.sql.*;
import java.lang.*;
import java.io.*;

public class Ndb2Tomcat{

   public static void main(String args[]) {


  try{
     Class.forName("COM.ibm.db2.jdbc.net.DB2Driver");
     }
     catch( ClassNotFoundException e2)
     {
      System.out.println("\nJDBC Driver class not found exception");
     }
     catch( Exception e)
     {
       System.out.println("\nDriver class not found exception");

    }
    try{
       Connection con = null;
      String url = "jdbc:db2://100.3.13.34/SAMPLE";
       con = DriverManager.getConnection(url,"db2admin", "db2pwd");

        // retrieve data from the database
       System.out.println("Retrieve some data from the database...");

       Statement stmt = con.createStatement();
       ResultSet rs = stmt.executeQuery("SELECT * from db2admin.employee
order by firstnme");

       System.out.println("Received results:");

       while (rs.next())
       {
          String a = rs.getString(1);
          String str = rs.getString(2);
          System.out.print(" empno= " + a);
          System.out.print(" firstname= " + str);
          System.out.print("\n");
       }
       rs.close();
      stmt.close();
       con.close();
     }
     catch (SQLException e1)
     {
          e1.printStackTrace();
     }

   }

----------------------------------------------------------------------------

--------

Nishant Awasthi





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