Removing Record

Question

String login="",title="",subject="";
          int co_id=0,i,watch_id=0,remove=0;
          String aa=req.getParameter("remove");
          if(aa !=null){
          remove=Integer.parseInt(aa);
          String sql="delete from watchlist where watch_id="+remove;
          PreparedStatement ps=cnn.prepareStatement(sql);
          ps.executeUpdate();
          cnn.commit();
          ps.close();
          }else{
          if(login !=null){
          login=req.getParameter("login");
          String sql="select co_id from co_login where login='"+login+"'";
          PreparedStatement ps=cnn.prepareStatement(sql);
          rs=ps.executeQuery();
          if(rs.next()){
          co_id=rs.getInt(1);
          out.println("<table border=0 width=100%><tr><td><table border=0 cellspacing=9 cellpadding=1 align=center>"+
          "<tr bgcolor=#E7E1E1><td><font color=blue><b>Title</b></font></td><td><font color=blue><b>Subject</b></font></td><td><font color=blue><b>Action</b></font></td></tr>");
          String sql5="select watch_id,title,subject from watchlist where co_id="+co_id;
          PreparedStatement ps5=cnn.prepareStatement(sql5);
          rs=ps5.executeQuery();
          while(rs.next()){
          watch_id=rs.getInt(1);
          title=rs.getString(2);
          subject=rs.getString(3);
          out.println("<tr><td>"+title+"</td><td>"+subject+"</td><td>"+
          "<a href=http://localhost:5050/examples/servlet/viewFavorite?remove="+watch_id+">[ Remove ]</a>     "+
          "<a href=javascript:history.back()>[ Back ]</a></td></tr>");
          ps.close();
          ps5.close();
}I am trying to delete a record and to show the same page. it delete the record but blank page appears. can you help me
TIA

Answer 1

cotton.m knows me - I'm one of those guys who freaks
out. 8)
I might feel a little better if this code was in a
JSP. This is example is far worse. It looks like a
snippet of servlet code that actually writes
hardcoded HTML to the servlet output stream.
But wait, it gets worse.
S/he's even hardcoded page navigation into the
generated HTML. If the navigation changes, the app
has to be recompiled.
Your JDBC is bad; your servlet code is worse. If you
continue this way, you'll live to regret it in
maintainence.
Learn JSTL. And MVC-2. There are a million
frameworks for web MVC out there. You can even roll
your own easily if you don't want to depend on
someone else. (I did once, for education's sake.)
Just don't do this. It's been discredited ever
since the earliest invention of the servlet.
%duffymo: know what you say about this code??
String subject="",message="",offer_id="",coid="";
          int offerid=0,co_id=0;
          message=req.getParameter("message");
          offer_id=req.getParameter("offerid");
          coid=req.getParameter("co_id");
          if(offer_id !=null && coid !=null){
          offerid=Integer.parseInt(offer_id);
          co_id=Integer.parseInt(coid);
String sql="select subject from oi where oi_id="+offerid;
PreparedStatement ps=cnn.prepareStatement(sql);
          rs=ps.executeQuery();
          if(rs.next()){
          subject=rs.getString(1);
out.println("<center><br><b>Subject</b><font color=olive><b> "+subject+"</b></font>");
out.println("<form action='http://localhost:5050/examples/servlet/reply'>"+
"<textarea class=khan rows=18 cols=70 name=message></textarea><br>"+
"<input type=button class=khan onClick='javascript:history.back()' value=' Back '>"+
"<input type=submit class=khan  value=' Send '></form>");
     if(message !=null){
          String sql5="insert into oi_reply(oi_id,co_id,message) values("+offerid+","+co_id+",'"+message+"')";
          PreparedStatement ps5=cnn.prepareStatement(sql5);
          ps5.executeUpdate();
          res.sendRedirect("http://localhost:5050/examples/servlet/displayOffers");
     }