Update Database from jsp

I want to update my oracle database column from a text box ,so whenever I input some text value in the text box and click UPDATE button the database field should be updated . I have a drop down menu also ,so when ever I select the drop down and enter in the text box that field should be updated. I have written the code but its not working . Please help me out its Urgent.

<%@ page language="java" import="java.sql.*" %> <%@ page import = "java.io.*"%>

   <% 

      String id = request.getParameter("ID");
     int num=Integer.parseInt(id);

       String url= request.getParameter("URL");


     %>

    <%

    try{

    Connection conn = null;

    Class.forName("oracle.jdbc.OracleDriver"); 

    conn = DriverManager.getConnection("jdbc:oracle:thin:SCOTT/tiger@computer_1:1521:orcl");

    Statement st= null;

    st=conn.createStatement();
    st.executeUpdate("UPDATE TEST_LINKS SET URL= '"+url+"'WHERE ID= '"+num+"' ");

      }
    catch(Exception e){
    System.out.println(e);
        }
      %>