Question

At many places in my web application I need a certain String which is :

request.getServletContext().getRealPath("/"); 
// I can only get this once the web-app starts

Sometimes a simple java class needs to know this string. I don’t want to pass each and every time this string to the class’s function. One way could be to stash this string in a file at the very beginning of the web application. Every time I would need this, simply read the file.But this doesn’t seem a pretty good option. Is there any other way out ?

May be I can store in the context.xml of the application. If it is possible how do I do that ?

If there is a better way please suggest.

I am using tomcat as the server.

Answer 1

Invoke run the following code when your application starts (e.g. with a ServletContextListener):

public void contextInitialized(ServletContextEvent sce) {
   ServletContextRootRealPath.set(sce.getServletContext().getRealPath("/"));
}

Then later whenever you need it you simply call

ServletContextRootRealPath.get()

Since it’s all static the variable is accessible JVM-wide to every code that runs in this JVM.

Utility class

public final class ServletContextRootRealPath {
  private static String path;

  private ServletContextRootRealPath() {
    // don't instantiate utility classes
  }

  public static void set(String rootRealPath) {
    path = rootRealPath;
  }

  public static String get() {
    return path;
  }
}