[java] What does this expression language ${pageContext.request.contextPath} exactly do in JSP EL?

The pageContext is an implicit object available in JSPs. The EL documentation says

The context for the JSP page. Provides access to various objects including:
servletContext: ...
session: ...
request: ...
response: ...

Thus this expression will get the current HttpServletRequest object and get the context path for the current request and append /JSPAddress.jsp to it to create a link (that will work even if the context-path this resource is accessed at changes).

The primary purpose of this expression would be to keep your links 'relative' to the application context and insulate them from changes to the application path.


For example, if your JSP (named thisJSP.jsp) is accessed at http://myhost.com/myWebApp/thisJSP.jsp, thecontext path will be myWebApp. Thus, the link href generated will be /myWebApp/JSPAddress.jsp.

If someday, you decide to deploy the JSP on another server with the context-path of corpWebApp, the href generated for the link will automatically change to /corpWebApp/JSPAddress.jsp without any work on your part.

Examples related to java

Under what circumstances can I call findViewById with an Options Menu / Action Bar item? How much should a function trust another function How to implement a simple scenario the OO way Two constructors How do I get some variable from another class in Java? this in equals method How to split a string in two and store it in a field How to do perspective fixing? String index out of range: 4 My eclipse won't open, i download the bundle pack it keeps saying error log

Examples related to jsp

Difference between request.getSession() and request.getSession(true) A child container failed during start java.util.concurrent.ExecutionException The superclass "javax.servlet.http.HttpServlet" was not found on the Java Build Path Using if-else in JSP Passing parameters from jsp to Spring Controller method how to fix Cannot call sendRedirect() after the response has been committed? How to include js and CSS in JSP with spring MVC How to create an alert message in jsp page after submit process is complete getting error HTTP Status 405 - HTTP method GET is not supported by this URL but not used `get` ever? How to pass the values from one jsp page to another jsp without submit button?

Examples related to el

Identifying and solving javax.el.PropertyNotFoundException: Target Unreachable Adding external resources (CSS/JavaScript/images etc) in JSP How does EL empty operator work in JSF? javax.el.PropertyNotFoundException: Property 'foo' not found on type com.example.Bean How to use && in EL boolean expressions in Facelets? How do I check two or more conditions in one <c:if>? The representation of if-elseif-else in EL using JSF Use JSTL forEach loop's varStatus as an ID What does this expression language ${pageContext.request.contextPath} exactly do in JSP EL? How to access at request attributes in JSP?