Implement custom resources in JBoss Seam

When I was developing my Seam application I found it is hard to render a picture with byte array from database. You can use s:graphicImage to display a picture inside a web page. However I found that it is merely impossible to render a picture individually with facelets in.

The solution is to write a custom resource component. First you need to define a new class which extends org.jboss.seam.web.AbstractResource as your custom resource component. Register this component as resource provider like this:

 org.jboss.seam.core.Init.instance().addResourceProvider("your_component_name");

Normally you can declear this in a @Create method of a application scope component.

Then you can write your codes in getResource() method. I paste my codes here. Hope that it can give you a little help.

package net.ondev.demo; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import net.ondev.demo.ImageDao; import net.ondev.demo.ImageData; import org.jboss.seam.Component; import org.jboss.seam.ScopeType; import org.jboss.seam.annotations.Create; import org.jboss.seam.annotations.In; import org.jboss.seam.annotations.Logger; import org.jboss.seam.annotations.Name; import org.jboss.seam.annotations.Scope; import org.jboss.seam.annotations.Startup; import org.jboss.seam.annotations.intercept.BypassInterceptors; import org.jboss.seam.core.Init; import org.jboss.seam.log.Log; import org.jboss.seam.servlet.ContextualHttpServletRequest; import org.jboss.seam.web.AbstractResource; @Scope(ScopeType.APPLICATION) @Name("ImageResource") @Startup @BypassInterceptors public class ImageResource extends AbstractResource implements java.io.Serializable { //http://www.ondev.net/post/show/663 @Logger Log log; @Override public void getResource(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { // Wrap this, we need an ApplicationContext new ContextualHttpServletRequest(request) { @Override public void process() throws IOException { doWork(request, response); } }.run(); } protected void doWork(HttpServletRequest request, HttpServletResponse response) throws IOException { String pathInfo = request.getPathInfo().substring( getResourcePath().length() + 1); try { Integer imageId = new Integer(pathInfo); ImageDao imageDao = (ImageDao)Component.getInstance("imageDao"); ImageData image = imageDao.queryById(ImageData.class, imageId); response.addHeader("Cache-Control", "max-age=600"); // 10 minutes freshness in browser cache response.setContentType(image.getContentType()); response.setContentLength(image.getData().length) ; response.getOutputStream().write(image.getData()); response.getOutputStream().flush(); } catch (Exception e) { log.error(e); response.sendError(HttpServletResponse.SC_BAD_REQUEST, "Invalid image id"); } } @Create public void init(){ org.jboss.seam.core.Init.instance().addResourceProvider("ImageResource"); } @Override public String getResourcePath() { return "/images"; } }

Note that you need to add your Seam's resource path before the string you defined in getResourcePath(). For example, in this example, people can access the image via http://<your_domain>/seam/resource/images/<image_id>