java通过commons-fileupload实现多张图片的上传（jsp页面）

<div id="middle">
                  <div id="form">
                  <form action="ProductInfoServlet?tag=add" method="post" enctype="multipart/form-data" >
                    <h2>三只松鼠--新增</h2>
                   <table align="center">
                   <tr>
                   <td width="90px"  class="td">类型：</td>
                   <td width="200px" >
                     <select name="typename">
                          <option>---请选择--</option>
                          <c:forEach items="${tlist }" var="type" varStatus="status">
                          <option value="${type.typeId}">${type.typeName }</option>
                          </c:forEach>
                         </select>
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">品牌：</td>
                   <td width="200px" >
                     <select name="brand">
                          <option>---请选择--</option>
                          <option >三只松鼠</option>
                         </select>
                    </td>
                   </tr>
                    <tr>
                   <td width="90px"  class="td">名称：</td>
                   <td>
                   <input type="text" name="produceName" id="name">
                    </td>
                   </tr>
                    <tr>
                   <td width="90px"  class="td">详情介绍：</td>
                   <td>
                   <textarea cols="20px" rows="1px" name="details"></textarea>
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">价格：</td>
                   <td>
                  <input type="text" name="price" id="price">
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">库存：</td>
                   <td>
                  <input type="text" name="stock" id="price">
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">大图:</td>
                   <td>
                  <input type="file" name="bigfile" id="price">
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">小图1:</td>
                   <td>
                  <input type="file" name="smallfile1" id="price">
                    </td>
                   </tr>
                   <tr>
                   <td width="90px"  class="td">小图2:</td>
                   <td>
                  <input type="file" name="smallfile2" id="price">
                    </td>
                   </tr>
                    <tr>
                   <td width="90px"  class="td">小图3:</td>
                   <td>
                  <input type="file" name="smallfile3" id="price">
                    </td>
                   </tr>
                   <tr>
                   <td colspan="2"><input type="submit" value="新增">   <input type="button" value="取消"></td>
                   </tr>
                    </table>
                 </form>
                 </div>
	           </div><div id="middle">
                  <div id="fo