When importing CSS stylesheets by <h:outputStylesheet>, the stylesheet is imported and processed by the FacesServlet through /javax.faces.resource/*. Look at the generated <link> element pointing to the stylesheet in question and you’ll understand.
You have to change all url() dependencies to use #{resource['library:location']} instead. JSF will then auto-substitute it with the right path. Given your folder structure, you need to replace
.c2 {
background: url("/resources/images/smiley.jpg");
}
by
.c2 {
background: url("#{resource['images/smiley.jpg']}");
}
Assuming that your webapp context name is playground and that your FacesServlet is mapped on *.xhtml, then the above should end up in the returned CSS file as follows
.c2 {
background: url("/playground/javax.faces.resource/images/smiley.jpg.xhtml");
}
Noted should be that the JSF implementation will for determine only during the first request on the CSS file if it contains EL expressions. If it doesn’t then it will for efficiency not anymore attempt to EL-evaluate the CSS file content. So if you add an EL expression to a CSS file for the first time, then you’d need to restart the whole application in order to get JSF to re-check the CSS file.
In case you wanted to reference a resource from a component library such as PrimeFaces, then prefix the library name, separated with :. E.g. when you’re using PrimeFaces “Start” theme which is identified by primefaces-start
.c2 {
background: url("#{resource['primefaces-start:images/ui-bg_gloss-wave_50_6eac2c_500x100.png']}");
}
This will be generated as
.c2 {
background: url("/playground/javax.faces.resource/images/ui-bg_gloss-wave_50_6eac2c_500x100.png.xhtml?ln=primefaces-start");
}
See also:
- How to reference CSS / JS / image resource in Facelets template?
- Changing JSF prefix to suffix mapping forces me to reapply the mapping on CSS background images
Unrelated to the concrete problem, the way how you use the library is not entirely right. It’s meant to be the common identifier/subfolder of all related CSS/JS/image resources. The key idea is to be able to change the entire look’n’feel by just changing the library (which can be done by EL). You seem however to be relying on the default library. In that case, you could just omit the library from your <h:outputStylesheet> and #{resource}.
<h:outputStylesheet name="css/style.css" />