Include another JSP file

在JSP中，有兩種 include

<%@include file="includes/header.jsp" %>

What you’re doing is a static include. A static include is resolved at compile time, and may thus not use a parameter value, which is only known at execution time.

What you need is a dynamic include:

<jsp:include page="..." />

Note that you should use the JSP EL rather than scriptlets. It also seems that you’re implementing a central controller with index.jsp. You should use a servlet to do that instead, and dispatch to the appropriate JSP from this servlet. Or better, use an existing MVC framework like Stripes or Spring MVC.

• 第一種, 沒有 page= 的include會在編譯時期（轉換成servlet）就將file include進來，最後只會有一個.class檔案.
• 第二種, 有 page= 的include, 在編譯時期並不會被編譯，是在client request時，才會動態的去載入在去編譯。

---

如果要帶參數, You can use parameters like that

<jsp:include page='about.jsp'>
    <jsp:param name="articleId" value=""/>
</jsp:include>

and

in about.jsp you can take the paramter

<%String leftAds = request.getParameter("articleId");%>

---

You can use Include Directives

<%
 if(request.getParameter("p")!=null)
 { 
   String p = request.getParameter("p");
%>    

<%@include file="<%="includes/" + p +".jsp"%>"%>

<% 
 }
%>

or JSP Include Action

<%
 if(request.getParameter("p")!=null)
 { 
   String p = request.getParameter("p");
%>    

<jsp:include page="<%="includes/"+p+".jsp"%>"/>

<% 
 }
%>

資料來源:
https://stackoverflow.com/questions/9110148/include-another-jsp-file