java web 编写资料

(1)在Servlet中放回一个参数aa，在界面上显示出aa所对应的值，比如显示“取款100元整”

request.setAttribute("aa", "取款"+QuKuanJinE + "整！");
            // ////////跳转界面
            request.getRequestDispatcher("QuKuan.jsp").forward(request,response);

<tr>
            <td colspan="3" align="center"><font color="#FF0000">${aa}</font>
                <input type="button" value="返回"
                onclick="window.location='index.jsp'"></td>
        </tr>