jsp跳转问题,不能显示数据库数据，并且不能跳转

展示商品不跳转也不显示后台数据

• https://ask.csdn.net/new?word=&spm=1001.2014.3001.5354#
  • https://ask.csdn.net/new?word=&spm=1001.2014.3001.5354#goods
    https://ask.csdn.net/new?word=&spm=1001.2014.3001.5354#添加商品信息

  •             <li class="nav-item"><a class="nav-link" data-toggle="collapse" href="#goodstype">商品类型管理 </a>                <div id="goodstype" class="collapse" data-parent="#menu">                    <div class="list-group">                        <a href="#" class="list-group-item list-group-item-action" id="getgoodstype">查看商品类型</a>                        <a href="#" class="list-group-item list-group-item-action" id="addGoodsType">添加商品类型</a>                    </div>                </div></li>        </div>    </ul>    <div id="content-wrapper" class="d-flex flex-column">            <nav class="shadow mb-3 navbar navbar-expand navbar-while bg-while static-top justify-content-end">              <ul class="navbar-nav">                <li class="nav-item"><a href="#">admin </a></li>              </ul>        </nav>        <iframe class="dv_content flex-grow-1" frameborder="0" scrolling="yes">                      </iframe>        <footer>           <div class="container bg-white mb-3 p-3">             <div class="copyright text-center">版权所有&copy; 东华理工大学长江学院 2020</div>           </div>        </footer>    </div></div>