javascript - How to setup a RequestHandler for images with VaadinServlet -

i want have requesthandler able dynamically create images @ mydomain/images/id8938748.jpg , @ same handle other traffic through standard vaadinservlet. understand need put requesthandler in vaadinservlet explained here extending such as:

public class mycustomservlet extends vaadinservlet  {         @override         protected void service(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception          {             getservice().addsessioninitlistener(new sessioninitlistener()              {                 @override                 public void sessioninit(sessioninitevent event) throws serviceexception                  {                     event.getsession().addrequesthandler(mycustomrequesthandlerforimages);                 }             });         } } 

my problem how register new mycustomservlet? looked @ doing in web.xml can't seem right.

my requesthandler simply:

@override public boolean handlerequest(vaadinsession session, vaadinrequest request, vaadinresponse response) throws ioexception  {     system.out.println("test it's being called"); } 

for web.xml have:

<servlet>     <servlet-name>mycustomvaadinservlet</servlet-name>     <servlet-class>         com.test.mycustomvaadinservlet     </servlet-class> </servlet>  <servlet-mapping>     <servlet-name>mycustomvaadinservlet</servlet-name>     <url-pattern>/images/*</url-pattern> </servlet-mapping> 

i have other servlet defined in ui code annotations:

public class myui extends ui {   @webservlet(value = "/*", asyncsupported = true)   @vaadinservletconfiguration(productionmode = false, ui = myui.class, widgetset = "com.mywidgetset")     public static class servlet extends vaadinservlet    {   }   ... } 

when call domain works expected , vaadin application works. when call domain/images or domain/images/randomtext empty page , system.out.println statements not outputted. requesthandler not called.

i have tried things mapping /images/* , /app/* didn't make difference...

if display images in vaadin ui using example image component, use resource. there several resource implementations available:

• themeresource: add file (e.g. image) theme , use reference image.
• Èxternalresource: file on url.
• classresource: file on classpath, vaadin servlet serves file browser.
• fileresource: file on filesystem of server. vaadin servlet serves file browser.

• streamresource: generate file inputstream. vaadin servlet serves file browser.

  image image = new image(); image.setsource(new themeresource("path/is/relative/to/the/theme/folder.png")); 

a valid alternative create regular servlet generates , serves files. cannot map vaadin servlet context root anymore. use externalresource reference files in vaadin code:

image image = new image(); image.setsource(new externalresource("/images/id8938748.jpg")); 

your servlet mapping example follows:

<servlet-mapping>   <servlet-name>myimageservlet</servlet-name>   <url-pattern>/images/*</url-pattern> </servlet-mapping>  <servlet-mapping>   <servlet-name>myvaadinservlet</servlet-name>   <url-pattern>/ui/*</url-pattern> </servlet-mapping>  <servlet-mapping>   <servlet-name>myvaadinservlet</servlet-name>   <url-pattern>/vaadin/*</url-pattern> </servlet-mapping>