Accessing URL mappings of a servlet in Tomcat with only static functions

Question

I need to use URL-mapping for my servlet which is set in web.xml. Currently I can read the mappings with the following code in the processRequest function.

Iterator<String> urlMappings = this.getServletContext().getServletRegistration(MyServletClass.class.getSimpleName()).getMappings().iterator();
while (urlMappings.hasNext()) {
    System.out.println(urlMappings.next());
}

However getServletContext function is not static and therefore I cannot read it without an instance of the servlet. That is also OK but if there is a way to do this with only static functions I will prefer that solution. Any help?

I am using Tomcat 8.0.3 and JDK 1.8

Answer 1

Add a ServletContextListener to your web.xml. This will be called when your webapp is loaded. In the contextInitialized() method you can store the ServletContext in a static variable for example for later use. Then you will be able to access the ServletContext in a static way:

class MyListener implements ServletContextListener {

    public static ServletContext context;

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        context = sce.getServletContext();
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        context = null;
    }

}

Add it to web-xml like this:

<web-app>
    <listener>
        <listener-class>
            com.something.MyListener
        </listener-class>
    </listener>
</web-app>

And you can access it from anywhere like this:

MyListener.context.getServletRegistration(
    MyServletClass.class.getSimpleName()).getMappings().iterator();

Note:

You might want to store it as private and provide a getter method, and also check for null value before using it.