how to connect jdbc

package com.tcs.ilp.Try.Controller;

import java.io.IOException; import java.io.PrintWriter; import java.util.ArrayList;

import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpSession;

import com.tcs.ilp.Try.Model.Beans; import com.tcs.ilp.Try.Model.MyHelper;

/** * Servlet implementation class Servlet1 */ public class Servlet1 extends HttpServlet { private static final long serialVersionUID = 1L;

/**
 * Default constructor. 
 */
public Servlet1() {
    // TODO Auto-generated constructor stub
}

/**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
{











}

/**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException 
{
    HttpSession session=request.getSession();
    PrintWriter out=response.getWriter();
    out.println("Entred post");
    String str2=request.getParameter("submit");
    out.println(str2);
    //ArrayList<Beans> c=new ArrayList<Beans>();
    String str=request.getParameter("username");
    String str1=request.getParameter("password");

    ArrayList<Beans> a=new ArrayList<Beans>();

    if(str2.equals("Login"))
            {
        System.out.println("Entred if");

    //System.out.println(a);
        int d;
    d=MyHelper.insert(str,str1);
    //Beans b=new Beans();
    a=MyHelper.view();


    session.setAttribute("registration",a);
    response.sendRedirect("Reg_users.jsp");
            }
    if(str2.equals("Update"))
    {
        MyHelper.update(str,str1);
    }
    if(str2.equals("logout"))
    {
        session.invalidate();
        System.out.println("Successfully Deleted");
    }
}

}