index.html

<html><body>
<h1 align = "center">Beer Selection Page</h1>
<form method="POST"
      action="SelectBeer.do">
  Select beer characteristics<p>
  Color:
  <select name="color" size="1">
    <option value="light"> light </option>
    <option value="amber"> amber </option>
    <option value="brown"> brown </option>
    <option value="dark"> dark </option>k
  </select>
  <br><br>
  <center>
    <input type="SUBMIT">
  </center>
</form></body></html>

web.xml

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
    <servlet-name>Ch3 Beer</servlet-name>
    <servlet-class>com.example.web.BeerSelect</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Ch3 Beer</servlet-name>
    <url-pattern>/SelectBeer.do</url-pattern>
  </servlet-mapping>
</web-app>

BeerSelect.java

package com.example.web;

import com.example.model.*;
import jakarta.servlet.*;
import jakarta.servlet.http.*;

import java.io.*;
import java.util.*;

public class BeerSelect extends HttpServlet {
    public void doPost(HttpServletRequest request,
                       HttpServletResponse response)
            throws IOException, ServletException {
        String c = request.getParameter("color");
        BeerExpert be = new BeerExpert();
        List result = be.getBrands(c);
        // response.setContentType("text/html");
        // PrintWriter out = response.getWriter();
        // out.println("Beer Selection Advice<br>");
        request.setAttribute("styles", result);
        RequestDispatcher view =
                request.getRequestDispatcher("result.jsp");
        view.forward(request, response);
    }
}

BeerExpert.java

package com.example.model;

import java.util.*;

public class BeerExpert {
    public List getBrands(String color) {
        List brands = new ArrayList();
        if (color.equals("amber")) {
            brands.add("Jack Amber");
            brands.add("Red Moose");
        } else {
            brands.add("Jail Pale Ale");
            brands.add("Gout Stout");
        }
        return (brands);
    }
}

result.jsp

<%@ page import="java.util.*" %>
<html>
<body>
<h1 align=“center“>Beer Recommendations JSP</h1>
<p>
    <%
        List styles = (List) request.getAttribute("styles");
        Iterator it = styles.iterator();
        while (it.hasNext()) {
            out.print("<br>try: " + it.next());
        }
    %>
</p>
</body>
</html>