[問題] compile java檔時遇到錯誤-package does not exist

[RichFU (小富哥~~~)]

各位前輩好，小弟最近開始學習servlet
在做 Head First 第三章的範例時compile java檔遇到問題無法解決，
可以幫忙一下嗎？詳情如下

目錄架構為:

java檔
D:\Java\SCWCD\beerV1\src\com\sample\model\BeerExpert.java
package com.sample.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);
        }

}

D:\Java\SCWCD\beerV1\src\com\sample\web\BeerSelect.java

package com.sample.web;

import com.sample.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;charset=big5");
                PrintWriter out = response.getWriter();
                out.println("Beer suggest list<br>");
                String c = request.getParameter("color");

                BeerExpert be = new BeerExpert();
                List result = be.getBrands(c);
                Iterator it = result.iterator();
                while(it.hasNext()){
                        out.print("<br>try it: "  + it.next() );
                }
        }
}


compile步驟如下：
(1)於D:\Java\SCWCD\beerV1目錄下compile BeerExpert.java 成功compile
   且class檔位於：
   D:\Java\SCWCD\beerV1\classes\com\sample\model\BeerExpert.class
(2)再於D:\Java\SCWCD\beerV1目錄下compile BeerExpert.java compile卻失敗…

以下是錯誤訊息

D:\Java\SCWCD\beerV1>javac -d classes src/com/sample/web/BeerSelect.java
src/com/sample/web/BeerSelect.java:3: package com.sample.model does not exist
import com.sample.model.*;
^
src/com/sample/web/BeerSelect.java:17: cannot find symbol
symbol  : class BeerExpert
location: class com.sample.web.BeerSelect
                BeerExpert be = new BeerExpert();
                ^
src/com/sample/web/BeerSelect.java:17: cannot find symbol
symbol  : class BeerExpert
location: class com.sample.web.BeerSelect
                BeerExpert be = new BeerExpert();
                                    ^
3 errors

請問這是哪邊錯了呢？一直找不出來……可以請前輩們幫忙解答一下嗎？謝謝！

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◆ From: 123.240.166.19
推 H45:顯然是 classpath 之設定有誤...
→ RichFU:請問該如何設定呢？我環境變數classpath設:
→ RichFU:C:\Tomcat 5.5\common\lib\servlet-api.jar還有什麼須設呢?
→ RichFU:似乎成功了耶！感謝H前輩 ^^