title: Java Servlet DB Query with Ajax - slow query time and querystring not always fully passed to the servlet
body: <p>I'm trying to create a AJAX based SQL query with Java EE and Servlets. I'm using Glassfish 3.01 and MS SQL server with Jquery on the client side. 
  I put everything together, and bind my ajax function to the textfield's onkeyup event. But sometimes When I put 'teststring' into the textbox only "teststrin" passed to the Servlet. So basically the last char disappears and therefore the query result is not correct.
  Not to mention when the resultset contains large amount of data the query is pretty slow. Could you please check if I'm doing something wrong on the server and client side?  </p>
  
  <p>On the client side I have this JQuery function:
  <pre>
    function ajaxSearch(sstring) {</p>
  
  <p>if (sstring.length &lt; 3)
    {
        $("#external").html("<p>at least 3 chars please....</p>")
    }
    else
    {
      $('#loading').ajaxStart(function() {
        $(this).show()
        $("#external").hide()
      });</p>
  
  <pre><code>$('#loading').ajaxComplete(function() {
    $(this).hide()
    $("#external").show()
  });
  
  $.ajax({
      type:"GET",
      url: "/myApp/getStd",
      dataType: "application/x-www-form-urlencoded",
      data: "sstring="+escape(sstring),
              async: true,
      success: function(data){
          $("#external").html(data);
  
      }
   })
  </code></pre>
  
  <p>}
  }</p>
  
  <p>On the server side I have this:</p>
  
  
  @WebServlet(name="getStd", urlPatterns={"/getStd"})
      public class getStd extends HttpServlet {
     @Override
     public void doGet (HttpServletRequest req, HttpServletResponse res) throws           ServletException, IOException {
              Connection conn = null;
              Statement stmt = null;  
              ResultSet rs = null;
              ArrayList rows = new ArrayList();
              res.setCharacterEncoding("UTF-8");
              res.setContentType("text/html");
              PrintWriter out =  res.getWriter();
              String sql=null;
              String test= req.getParameter("sstring");
      try{
              InitialContext cxt = new InitialContext();
              if (cxt == null) {
               throw new Exception("Uh oh -- no context!");}
             DataSource ds = (DataSource) cxt.lookup( "jdbc/Sample" );
             conn = ds.getConnection();
             stmt = conn.createStatement();
             sql="Select * from MYDB.dbo.testdb where myField like '%"+req.getParameter("sstring")+"%';";
             rs = stmt.executeQuery(sql);
  
             while(rs.next()){
              stdRecord cols = new stdRecord();
              cols.setTeljel(rs.getString("Field1"));
              cols.setTitle(rs.getString("Field2"));
              cols.setICS(rs.getString("Field3"));
              cols.setREF(rs.getString("Field4"));
              rows.add(cols);
             }
  
             req.setAttribute("std", rows);
             req.setAttribute("query",test );
             req.getRequestDispatcher("/showRes.jsp").forward(req, res);
             // close everything to free up resources
             rs.close();
             rs = null;
             stmt.close();
             stmt = null;
             conn.close(); /
             conn = null;  
             rows=null;
          } catch (SQLException e) {
              e.printStackTrace(out);
          } catch (Exception e) {
              e.printStackTrace(out);
         } finally {
              if (rs != null) {
                try { rs.close(); } catch (SQLException e) { ; }
                rs = null;
      }
             if (stmt != null) {
              try { stmt.close(); } catch (SQLException e) { ; }
              stmt = null;
      }
            if (conn != null) {
             try { conn.close(); } catch (SQLException e) { ; }
             conn = null;
      }
  
         }
      }
    }
  
  
  </pre>
  
  <p>Thanks in advance. </p>