Any clever ways of handling the context in a web app?

Question

In Java, web apps are bundled in to WARs. By default, many servlet containers will use the WAR name as the context name for the application.

Thus myapp.war gets depl

Answer 1

For HTML pages, I just set the HTML tag. Every relative link (i.e. not starting with scheme or /) will become relative to it. There is no clean way to grab it immediately by HttpServletRequest, so we need little help of JSTL here.

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

${req.requestURL}
${req.requestURI}



  
    
    
    
  
  
    
    link
  

This has in turn however a caveat: anchors (the #identifier URL's) will become relative to the base path as well. If you have any of them, you would like to make it relative to the request URL (URI) instead. So, change like

jump

to

jump

---

In JS, you can just access the element from the DOM whenever you'd like to convert a relative URL to an absolute URL.

var base = document.getElementsByTagName("base")[0].href;

Or if you do jQuery

var base = $("base").attr("href");

---

In CSS, the image URLs are relative to the URL of the stylesheet itself. So, just drop the images in some folder relative to the stylesheet itself. E.g.

/css/style.css
/css/images/foo.png

and reference them as follows

background-image: url('images/foo.png');

If you rather like to drop the images in some folder at same level as CSS folder

/css/style.css
/images/foo.png

then use ../ to go to the common parent folder

background-image: url('../images/foo.png');

See also:

• Is it recommended to use the html tag?