How to use relative paths without including the context root name?
JspServletsResourcesRelative PathContextpathJsp Problem Overview
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?
Jsp Solutions
Solution 1 - Jsp
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:
Solution 2 - Jsp
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>
Solution 3 - Jsp
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.
Solution 4 - Jsp
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="${pageContext.request.contextPath}/jsp/sample.jsp">....</a>
It's worth to get familiar with tags
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
There is also jsp method to do it like below, but better way like above:
<link rel="stylesheet" href="<%=request.getContextPath()%>/style/sample.css" />
<script type="text/javascript" src="<%=request.getContextPath()%>/js/sample.js"></script>
To simply make a link:
<a id=".." class=".." href="<%=request.getContextPath()%>/jsp/sample.jsp">....</a>
Solution 5 - Jsp
This could be done simpler:
<base href="${pageContext.request.contextPath}/"/>
All URL will be formed without unnecessary domain:port but with application context.
Solution 6 - Jsp
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">