how to create servlet

package com.controller;

import java.io.IOException;

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

import com.beans.SampleBean;
import com.dao.*;
/**
 * Servlet implementation class Controller
 */
public class Controller extends HttpServlet {
    private static final long serialVersionUID = 1L;
    String searchNameGlobal=null;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Controller() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub

        if(request.getParameter("page").equalsIgnoreCase("create"))
    {
        SampleBean sample=new SampleBean();
        sample.setFname(request.getParameter("fname")); 
        sample.setLname(request.getParameter("lname"));
        sample.setAge(Integer.parseInt(request.getParameter("age")));
        sample.setGender(request.getParameter("gender"));
        sample.setPhone(request.getParameter("phone"));
        DbAccess newAccess=new DbAccess();
        try
        {
            newAccess.createStudent(sample);
        }
        catch(Exception e)
        {
            System.out.println("Error in controller create");
        }

    }
    else if(request.getParameter("page").equalsIgnoreCase("view"))
    {
        SampleBean sampleView=new SampleBean();
        DbAccess dbAccess=new DbAccess();
        try
        {
            String searchName=request.getParameter("fname");

            sampleView=dbAccess.viewStudent(searchName);
            request.setAttribute("result", sampleView);
        }
        catch(Exception e)
        {
            System.out.println("Error in view controller");
        }
        RequestDispatcher rd=request.getRequestDispatcher("/jsp/ViewDetails.jsp");
        rd.forward(request,response);
    }
    else if(request.getParameter("page").equalsIgnoreCase("update"))
    {
        SampleBean sampleView=new SampleBean();
        DbAccess dbAccess=new DbAccess();
        try
        {
            searchNameGlobal=request.getParameter("fname");

            sampleView=dbAccess.viewStudent(searchNameGlobal);
            request.setAttribute("result", sampleView);
        }
        catch(Exception e)
        {
            System.out.println("Error in update controller");
        }
        RequestDispatcher rd=request.getRequestDispatcher("/jsp/UpdateDetails.jsp");
        rd.forward(request,response);
    }
    else if(request.getParameter("page").equalsIgnoreCase("updatedetails"))
    {

        SampleBean sampleUpdate=new SampleBean();
        sampleUpdate.setFname(request.getParameter("fname")); 
        sampleUpdate.setLname(request.getParameter("lname"));
        sampleUpdate.setAge(Integer.parseInt(request.getParameter("age")));
        sampleUpdate.setGender(request.getParameter("gender"));
        sampleUpdate.setPhone(request.getParameter("phone"));
        DbAccess dbAccess=new DbAccess();
        try
        {

            dbAccess.updateStudent(sampleUpdate,searchNameGlobal);
        }
        catch(Exception e)
        {
            System.out.println("Error in update controller");
        }
    }
    else if(request.getParameter("page").equalsIgnoreCase("delete"))
    {
        DbAccess accessObject=new DbAccess();
        try
        {
            String deleteName=request.getParameter("fname");
            accessObject.deleteStudent(deleteName);
        }
        catch(Exception e)
        {
            System.out.println("Error in delete controller");
        }
    }
    }


}
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