WebAppResourceLoader

aeden (Anthony Eden) — Sun, 17 Apr 2005 07:41:59 GMT

The following code is for loading Velocity resources (i.e. Velocity files) from a web application's ServletContext.



import java.io.InputStream;



import javax.servlet.ServletContext;



import org.apache.commons.collections.ExtendedProperties;

import org.apache.velocity.exception.ResourceNotFoundException;

import org.apache.velocity.runtime.resource.Resource;

import org.apache.velocity.runtime.resource.loader.ResourceLoader;



public class WebAppResourceLoader extends ResourceLoader {



    private static ServletContext context = null;



    public void init(ExtendedProperties extendedProperties) {



    }



    private static ServletContext getServletContext() {

        return context;

    }



    public static void setServletContext(ServletContext context) {

        WebAppResourceLoader.context = context;

    }



    /**

     * @see org.apache.velocity.runtime.resource.loader.ResourceLoader#getResourceStream(java.lang.String)

     */

    public InputStream getResourceStream(String name)

            throws ResourceNotFoundException {

        InputStream result = null;



        if (name == null || name.length() == 0) {

            throw new ResourceNotFoundException("No template name provided");

        }



        try {

            if (!name.startsWith("/"))

                name = "/" + name;



            result = getServletContext().getResourceAsStream(name);

        } catch (NullPointerException npe) {

            throw new ResourceNotFoundException("ServletContext not found");

        } catch (Exception fnfe) {

            throw new ResourceNotFoundException(fnfe.getMessage());

        }



        return result;

    }



    public boolean isSourceModified(Resource arg0) {

        return false;

    }



    public long getLastModified(Resource arg0) {

        return 0;

    }



}

Then to initialize Velocity:



    WebAppResourceLoader.setServletContext(servletContext);

    Properties props = new Properties();

    props.setProperty("resource.loader", "webapp");

    props.setProperty("webapp.resource.loader.description", 

        "Load from the ServletContext");

    props.setProperty("webapp.resource.loader.class",

        "package.WebAppResourceLoader");

    Velocity.init(props);

From then on out you can use #parse directives such as:



#parse("/WEB-INF/something.vm")

DZone Snippets: velocity code

WebAppResourceLoader