jsp学习之动态标签

<jsp:useBean id="counterBean"
             scope="request"
             class="bean.CounterBean" />　　　这段代码等效下面注释中的代码

<%--
<%
 bean.CounterBean counterBean = (bean.CounterBean)request.getAttribute("counterBean");
 if(counterBean == null) {
  counterBean = new bean.CounterBean();
  request.setAttribute("counterBean", counterBean);
 }
%>
--%>

 scope="request"
只有当scope="page" 时bean只是把类new了个新类，不进行属情的取值．