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