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How to use relative paths without including the context root name?
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Solved jspservletsresourcesrelative-pathcontextpath
S

6

80

To working my static file (CSS, JS) I have to write absolute path like /AppName/templates/style/main.css. Is there any solution, that I could write relative path like style/main.css?

Saturn answered 21/1, 2011 at 22:18 Comment(2)
Why (and where) do you have to write the full path? Nearly anywhere I can think of, style/main.css should work. There may well be places where it doesn't, but without your telling people what you're actually trying to do, it's going to be very hit-or-miss whether people can help you. – Practical
I just want to link css file to my jsp page. I didn't write explain, becouse it was the simplest and only use I can image, so I think that everybody guess. Even so: I'm sorry. My mistake... – Saturn
A
169

If your actual concern is the dynamicness of the webapp context (the "AppName" part), then just retrieve it dynamically by HttpServletRequest#getContextPath().

<head>
    <link rel="stylesheet" href="${pageContext.request.contextPath}/templates/style/main.css" />
    <script src="${pageContext.request.contextPath}/templates/js/main.js"></script>
    <script>var base = "${pageContext.request.contextPath}";</script>
</head>
<body>
    <a href="${pageContext.request.contextPath}/pages/foo.jsp">link</a>
</body>

If you want to set a base path for all relative links so that you don't need to repeat ${pageContext.request.contextPath} in every relative link, use the <base> tag. Here's an example with help of JSTL functions.

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
...
<head>
    <c:set var="url">${pageContext.request.requestURL}</c:set>
    <base href="${fn:substring(url, 0, fn:length(url) - fn:length(pageContext.request.requestURI))}${pageContext.request.contextPath}/" />
    <link rel="stylesheet" href="templates/style/main.css" />
    <script src="templates/js/main.js"></script>
    <script>var base = document.getElementsByTagName("base")[0].href;</script>
</head>
<body>
    <a href="pages/foo.jsp">link</a>
</body>

This way every relative link (i.e. not starting with / or a scheme) will become relative to the <base>.

This is by the way not specifically related to Tomcat in any way. It's just related to HTTP/HTML basics. You would have the same problem in every other webserver.

See also:

Automatize answered 21/1, 2011 at 22:41 Comment(13)
i dont use pageContext.request.contextPath and i dont see when i really need it i can change the project properties in netbeans for context can you explain more – Muire
${pageContext... not working for me. Just generates something like localhost:8080/profile/$%7BpageContext.request.context%7D/css/profile/ – Pell
@Matt: upgrade to at least JSP 2.0 (released a decade ago). Alternatively, use <c:out>. Being a complete ignorant and having very legacy software isn't a fair reason to downvote, btw. – Automatize
Thanks Balus for the kind words. How do I tell what version of JSP I have? – Pell
I know this is kinda old, but how would I be able to use ${pageContext.request.contextPath} in a jquery/js variable and use it like that instead of typing out '${pageContext.request.contextPath}' for every link? – Ennead
@Vnge: just let JSP print it as a JS variable? – Automatize
Thanks, that makes sense! after a bit of googling i found out i can just print out the variable between ${ } just like the pageContext – Ennead
Beware that the <base> tag approach can break relative urls such as <a href="?var=foo"> (yes, these are valid). If placed in for example /page.html, they will resolve to /?var=foo instead of /page.html?var=foo. – Cletuscleve
@Natix: Break? It's intented as base URL of all relative URLs. See also a.o stackoverflow.com/a/1889957 Just don't use it if it doesn't fit your technical implementation. – Automatize
It works for me without fn substring part. Is there a need to use fn substring here? – Grime
${pageContext.request.contextPath} is now just ${#request.contextPath} – Habiliment
@ImpulseTheFox: Nope. That's only the case when you're using some sort of MVC framework on top of JSP/Servlets. – Automatize
That base tag is brilliant, had no idea it existed. Thanks for the wonderful answer, again. – Darreldarrell
D
21

Just use <c:url>-tag with an application context relative path.

When the value parameter starts with an /, then the tag will treat it as an application relative url, and will add the application-name to the url. Example:

jsp:

<c:url value="/templates/style/main.css" var="mainCssUrl" />`
<link rel="stylesheet" href="${mainCssUrl}" />
...
<c:url value="/home" var="homeUrl" />`
<a href="${homeUrl}">home link</a>

will become this html, with an domain relative url:

<link rel="stylesheet" href="/AppName/templates/style/main.css" />
...
<a href="/AppName/home">home link</a>
Dustproof answered 22/11, 2015 at 14:32 Comment(0)
F
3

This could be done simpler: 

<base href="${pageContext.request.contextPath}/"/>

All URL will be formed without unnecessary domain:port but with application context.

Falgout answered 24/10, 2016 at 22:50 Comment(0)
S
2

You start tomcat from some directory - which is the $cwd for tomcat. You can specify any path relative to this $cwd.

suppose you have

home
- tomcat
 |_bin
- cssStore
 |_file.css

And suppose you start tomcat from ~/tomcat, using the command "bin/startup.sh".

~/tomcat becomes the home directory ($cwd) for tomcat

You can access "../cssStore/file.css" from class files in your servlet now

Hope that helps, - M.S.

Singleness answered 21/1, 2011 at 22:37 Comment(0)
S
2

Instead using entire link we can make as below (solution concerns jsp files)

With JSTL we can make it like: To link resource like css, js:

     <link rel="stylesheet" href="${pageContext.request.contextPath}/style/sample.css" />
     <script src="${pageContext.request.contextPath}/js/sample.js"></script>

To simply make a link:

     <a id=".." class=".." href="${pageContext.request.contextPath}/jsp/sample.jsp">....</a>

It's worth to get familiar with tags

   <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

There is also jsp method to do it like below, but better way like above:

   <link rel="stylesheet" href="<%=request.getContextPath()%>/style/sample.css" />
   <script type="text/javascript" src="<%=request.getContextPath()%>/js/sample.js"></script>

To simply make a link:

   <a id=".." class=".." href="<%=request.getContextPath()%>/jsp/sample.jsp">....</a>
Scabble answered 21/8, 2014 at 0:34 Comment(0)
U
-1

This is a derivative of @Ralph suggestion that I've been using. Add the c:url to the top of your JSP.

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<c:url value="/" var="root" />

Then just reference the root variable in your page:

<link rel="stylesheet" href="${root}templates/style/main.css">
Unequaled answered 21/3, 2016 at 16:59 Comment(0)

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