EL表达式中的取值顺序问题

<%
   pageContext .setAttribute(“a”,”page”);
   request.setAttribute("a", "request");
   session.setAttribute("a", "session");
   application.setAttribute(“a”,”application”);%＞
%>


${a}                  --对应pageContext 
${requestScope.a}     --对应request
${sessionScope.a}     --对应session
${applicationScope.a}   --对应application
 
搜索顺序：page-->request-->session-->application