request往jsp页面传输数据为null,但是xml的url路径下是有数据的

//servlet
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/html;charset=UTF-8");
List productList=null;
try {
productList = service.FindAllProduct();
} catch (SQLException e) {
e.printStackTrace();
}
if(productList!=null) {
//request域中存数据
req.setAttribute("productList", productList);
//转发给jsp
req.getRequestDispatcher("/admin/product/list.jsp").forward(req, resp);
}else{
System.out.println("查询失败");
}
}

    //jsp
    <%
                            System.out.println(request.getAttribute("productList"));
                        %>
                        <c:forEach items="${requestScope.productList}" var="product" varStatus="vs">
                            <tr onmouseover="this.style.backgroundColor = 'white'"
                                onmouseout="this.style.backgroundColor = '#F5FAFE';">
                                <td style="CURSOR: hand; HEIGHT: 22px" align="center"
                                                          width="18%">${vs.count}</td>
                                <td style="CURSOR: hand; HEIGHT: 22px" align="center"
                                    width="17%"><img width="40" height="45" src="${pageContext.request.contextPath}/${product.pimage}"></td>
                                <td style="CURSOR: hand; HEIGHT: 22px" align="center"
                                    width="17%">${product.pname}</td>
                                <td style="CURSOR: hand; HEIGHT: 22px" align="center"
                                    width="17%">product.shop_price</td>
                                <td style="CURSOR: hand; HEIGHT: 22px" align="center"
                                    width="17%">${product.is_hot==1?"是":"否"}</td>
                                <td align="center" style="HEIGHT: 22px"><a
                                        href="${ pageContext.request.contextPath }/admin/product/edit.jsp">
                                    <img
                                            src="${pageContext.request.contextPath}/images/i_edit.gif"
                                            border="0" style="CURSOR: hand">
                                </a></td>
                                <td align="center" style="HEIGHT: 22px"><a href="#"> <img
                                        src="${pageContext.request.contextPath}/images/i_del.gif"
                                        width="16" height="16" border="0" style="CURSOR: hand">
                                </a></td>
                            </tr>
                        </c:forEach>

debug一下productList = service.FindAllProduct(); 这个productList是不是空的，可能是解析XML的问题