Is request.getContextPath() necessary?

Question

I used to start a URL with request.getContextPath() for navigating any JSP files inside of the application. Since I can't pass it into a Javascript, I have a URL without it. The approach seems working so far. Does that mean that it isn't necessary to start a URL with request.getContextPath() ?

Answer 1

Using request.getContextPath() is handy if you are running a webapp that is not at the root context. For example, you can have 1 application running at the root context with 5 other apps on the same url running under their own context path - 1 url : multiple apps.
How your app is setup depends on how you use request.getContextPath(). For instance I use it frequently for path references in html snippets in my JSPs:
<script src="<%=request.getContextPath()%>/scripts/myDateFunction.js"></script>
<link rel="stylesheet" type="text/css" href="<%=request.getContextPath()%>/styles.css">Now no matter what context this runs under, I'll be garanteed it will look for the file under the requested context at it's root context:
http://localhost:8080/ = root context = "/"
http://localhost:8080/myApp/ = webapp "myApp" = "myApps" root context is "/myApp" + "/"
scripts lives in myApp:
myApp.war
-> /scripts/myDateFunctions.js
If I were to move my web application to a different context then I don't need any code changes as the request will always retrieve for me the correct context.
You can't exactly pass it to Javascript, but you can embed it in the javascript:
<script language="Javascript">
function goPage(pageName) {
     document.location="<%=request.getContextPath()%>/admin/myPage.jsp";
</script>When the server writes this to the browser it will replace the <%=request.getContextPath()%> with the correct value.
Regards,
Anthony