36-2: Servlet EL

1. EL 에 대하여 설명하시오.

• Expression Language
• It can print java literals.
• It can set and get with the 4 scopes in jsp.

2. 아래의 EL 객체를 예를 들어 설명하시오.

• pageContext
• pageScope
• sessionScope
• param

//code1 page1
	application.setAttribute("application_name", "application_value");
	session.setAttribute("session_name", "session_value");
	pageContext.setAttribute("page_name", "page_value");
	request.setAttribute("request_name", "request_value");

//code2 page2
	${applicationScope.application_name} <br/>
	${sessionScope.session_name} <br/>
	${pageScope.page_name} <br/>
	${requestScope.request_name} <br/>

<!-- code3 -->
<%
	String id = request.getParameter("id");
	String pw = request.getParameter("pw");
%>
	${param.id} 
	${param.pw}
	${param["id"]}
	${param["pw"]}

• param: It calls the value from the name.