java.sql.SQLException: Before start of result set

[Rax Wer]

Hello All,

I am creating a simple servlet, which is retrieving a value from the database. i am using eclipse IDE.

Here is the code.

  

import java.io.IOException;
import java.io.*;
import java.sql.*;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Servlet implementation class Ex
 */
public class Ex extends HttpServlet 
{
	
       /**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	Connection conn1;
       PrintWriter out;
       ResultSet rs ;        
       //Statement Stmt;
  
       public void init()
        {
          conn1 = null;
          out = null;
          rs = null;   
          //Stmt=null;

        }

         
      public  void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException 
          {
		
         out.println("alsdj asldk aslkd jas"); 
	    String url1 = "jdbc:mysql://localhost:3306/";
	    String dbName1 = "forum";
	    String driver = "com.mysql.jdbc.Driver";
	    String userName = "root"; 
	    String password = "root";
	    String ss="ransa";
	    out = res.getWriter();
		
	  try 
 
           {  String userid = null;
	      Class.forName(driver).newInstance();
	      conn1 = DriverManager.getConnection(url1+dbName1,userName,password);
	      Statement Stmt ;
	      String sql="SELECT userid from user where username='"+ss+"';";
	      Stmt=conn1.createStatement(); 
	       rs = Stmt.executeQuery(sql);
		  
		 while(rs.next())
		     {	    

                          userid=rs.getString(1);
                     }
	    
		 out.println(userid);
	      conn1.close();
	      rs.close();
	      Stmt.close();
	  
	    } 

          catch (Exception e) 
 
            {
	       out.println(e);
	       e.printStackTrace();
	    }
	
	
	}

}
  

Getting an error:



java.sql.SQLException: Before start of result set
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:910)
at com.mysql.jdbc.ResultSet.checkRowPos(ResultSet.java:692)
at com.mysql.jdbc.ResultSet.getStringInternal(ResultSet.java:5476)
at com.mysql.jdbc.ResultSet.getString(ResultSet.java:5420)
at Ex.doGet(Ex.java:39)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Unknown Source)


I do not understand, where i am wrong. Name of database, table, fileds are all right.
No typing error.

Please any help me with this thing.

[Campbell Ritchie]

Have you called next() before using the ResultSet? Try this Java™ Tutorials Page for more details.

[Campbell Ritchie]

Is the code throwing the Exception actually quoted here; it says at doGet but I can't seem to find doGet in your quoted code?

[Rax Wer]

Campbell Ritchie wrote:Is the code throwing the Exception actually quoted here; it says at doGet but I can't seem to find doGet in your quoted code?

Yes it is the same error, no doubt in that.

[Rax Wer]

Thanks for replying....

Campbell Ritchie wrote:Have you called next() before using the ResultSet? Try this Java™ Tutorials Page for more details.

I am a beginner to this, can you please write the thing you are actually suggesting. So that it can be Corrected properly..

[Jan Cumps]

(As Campbell Ritchie says)

The exception hapended in Ex.doGet
You posted the code of Ex.doPost

[edit: mistyped name]

[Rax Wer]

Hello Everyone..
I am not using doGet method at all. Posted the same code i sun and the error produced.. Thats why i am not getting the thing that if doPost is used there, why m getting

Error:
at Ex.doGet(Ex.java:39)

Also there no such errorneous code on line 39.

[Jan Cumps]

Can you check if the Ex class executed by your servlet container is compiled from the Ex class code that you show us?