Include another JSP file

I am currently trying to learn JSP. My question is, at present I used to include the header and footer of the page using:

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

and

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

But now, I have separated the page content also. So, if user clicks on a page, say products, it has to load the JSP file which is situated in: includes/pages/products.jsp So, the link to the user is like: <a href="index.jsp?p=products">Products</a>.

So, I have to get the p value and display the page based on it.

Following is what I have done so far.

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

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

<% 
 }
%>

So, how do I place the value of variable "p" in position of "page_name" ?

Or, is there any other method that I could use ?

In PHP, we could use the include() or include_once(). I am bit stuck in this 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.

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"%>"/>

<% 
 }
%>

the different is include directive includes a file during the translation phase. while JSP Include Action includes a file at the time the page is requested

I recommend Spring MVC Framework as your controller to manipulate things. use url pattern instead of parameter.

example:

www.yourwebsite.com/products

instead of

www.yourwebsite.com/?p=products

Watch this video Spring MVC Framework

At page translation time, the content of the file given in the include directive is ‘pasted’ as it is, in the place where the JSP include directive is used. Then the source JSP page is converted into a java servlet class. The included file can be a static resource or a JSP page. Generally, JSP include directive is used to include header banners and footers.

Syntax for include a jsp file:

<%@ include file="relative url">

Example

<%@include file="page_name.jsp" %>

1.<a href="index.jsp?p=products">Products</a> when user clicks on Products link,you can directly call products.jsp.

I mean u can maintain name of the JSP file same as parameter Value.

<%
 if(request.getParameter("p")!=null)
 { 
   String contextPath="includes/";
   String p = request.getParameter("p");
   p=p+".jsp";
   p=contextPath+p;

%>    

<%@include file="<%=p%>" %>

<% 
 }
%>

or

2.you can maintain external resource file with key,value pairs. like below

products : products.jsp

customer : customers.jsp

you can programatically retrieve the name of JSP file from properies file.

this way you can easily change the name of JSP file

For a reason I don't yet understand, after I used <%@include file="includes/footer.jsp" %> in my index.jsp then in the other jsp files like register.jsp I had to use <%@ include file="footer.jsp"%>. As you see there was no more need to use full path, STS had store my initial path.