How To Implement An Icon Streamer For Primefaces Graphicimage Component

This page render code samples for using primefaces graphic icon component. In this example nosotros are assuming that the byte information of an icon is stored inwards an entity too that entity is access past times its id. See the param id inwards #1.
The param id is read past times the streamer too purpose to fetch the entity that stores the byte[] data.
1.) In the JSF page, allow us define a graphicImage factor similar this:

<p:graphicImage id="serviceImage" cache="false"  value="#{customImageStreamer.image}" height="150"  width="150">  <f:param name="id" value="#{myService.entity.id}"></f:param> </p:graphicImage> 

2.) Let us define a generic icon streamer that nosotros tin sack extend.

 populace abstract course of educational activity ImageStreamer<T extends BaseEntity> {   populace StreamedContent getImage() throws IOException {   FacesContext context = FacesContext.getCurrentInstance();    if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {    // So, we're rendering the HTML. Return a stub StreamedContent hence    // that it volition generate correct URL.    homecoming novel DefaultStreamedContent();   } else {    // So, browser is requesting the image. Return a existent    // StreamedContent amongst the icon bytes.    Long id = Long.parseLong(context.getExternalContext().getRequestParameterMap().get("id"));    T obj = getPersistenceService().findById(id);    if (getImageArr(obj) != null) {     homecoming novel DefaultStreamedContent(new ByteArrayInputStream(getImageArr(obj)));    } else {     homecoming novel DefaultStreamedContent();    }   }  }   populace StreamedContent getImage(T obj) throws IOException {    // So, browser is requesting the image. Return a existent   // StreamedContent amongst the icon bytes.   if (getImageArr(obj) != null) {    homecoming novel DefaultStreamedContent(new ByteArrayInputStream(getImageArr(obj)));   } else {    homecoming novel DefaultStreamedContent();   }   }   protected byte[] downloadUrl(URL toDownload) {   ByteArrayOutputStream outputStream = novel ByteArrayOutputStream();   InputStream current = null;    stimulate {    byte[] chunk = novel byte[4096];    int bytesRead;    current = toDownload.openStream();     spell ((bytesRead = stream.read(chunk)) > 0) {     outputStream.write(chunk, 0, bytesRead);    }   } select grip of (IOException e) {    homecoming null;   } in conclusion {    if (stream != null) {     stimulate {      stream.close();     } select grip of (IOException e) {      homecoming null;     }    }   }    homecoming outputStream.toByteArray();  }   populace abstract PersistenceService getPersistenceService();   populace abstract byte[] getImageArr(T obj);  } 

3.) The actual course of educational activity implementation that streams the image. Note that it must endure applicationScoped.

@Named @ApplicationScoped populace course of educational activity StudentImageStreamer extends ImageStreamer {   @Inject  mortal StudentService studentService;   @Override  populace PersistenceService getPersistenceService() {   homecoming studentService;  }   @Override  populace byte[] getImageArr(Student obj) {   homecoming obj.getImageAsByteArr();  }  } 

If you lot bring approximately other course of educational activity that needs streaming for primefaces graphic image, too then but practice approximately other course of educational activity that extends ImageStreamer.

References:
http://stackoverflow.com/questions/8207325/display-dynamic-image-from-database-with-pgraphicimage-and-streamedcontent