关于Head First Servlet and JSP问题

web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4"> --><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> form.html
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Beer Selection Page</title>
</head><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>light
<option>amber
<option>brown
<option>dark
</select>
<br>
<br>
<center>
<input type="submit">
</center>
</form>
</body>
</html>BeerSelect.java
package com.example.web;[color=#FF0000]import com.example.model.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;public class BeerSelect extends HttpServlet
{
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
// response.setContentType("text/html");
// PrintWriter out = response.getWriter();
// out.println("Beer Selection Advice<br>");
String c = request.getParameter("color");
// out.println("<br>Got beer color " + c);BeerExpert be = new BeerExpert();
List result = be.getBrands(c);// Iterator it = result.iterator();
// while (it.hasNext())
// {
// out.print("<br>try: " + it.next());
// }request.setAttribute("styles", result);
RequestDispatcher view = request.getRequestDispatcher("result.jsp");
view.forward(request, response);
}
}[/color]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>
<head>
<title>Beer Recommendations JSP</title>
</head><body>
<h1 align="center">Beer Recommendations JSP</h1>
<p><%
List sytles = (List)request.getAttribute("styles");
Iterator it = sytles.iterator();
while (it.hasNext())
{
out.print("<br>try: " + it.next());
}
%>
</body>
</html>以上代码当编译BeerSelect.java时出错会提示com.example.model文件不存在可是明明导进来了啊，求高手回复！