전체 url이 http://trandent.com/board/Spring/detail/774 인 경우
1. domain 가져오기
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<c:set var="baseURL" value="${fn:replace(req.requestURL, fn:substring(req.requestURI, 0, fn:length(req.requestURI)), req.contextPath)}" />
-> ${baseURL} = http://trandent.com
2. path 가져오기
<c:set var="path" value="${requestScope['javax.servlet.forward.servlet_path']}" />
-> ${path} = /board/Spring/detail/774
3. result
${baseURL}${path} = http://trandent.com/board/Spring/detail/774
