I am working on an application where I would like to include dynamic XHTML content from a stream. To handle this I wrote a taghandler extension which dumps the dynamic XHTML content to output component as
UIOutput htmlChild = (UIOutput) ctx.getFacesContext().getApplication().createComponent(UIOutput.COMPONENT_TYPE);
htmlChild.setValue(new String(outputStream.toByteArray(), "utf-8"));
This works fine for XHTML content which has no JSF tags. If I have JSF tags in my dynamic XHTML content like <h:inputText value="#{bean.item}"/>
, then they're printed as plain text. I want them to render as input fields. How can I achieve this?
Essentially, you should be using an <ui:include>
in combination with a custom ResourceHandler
which is able to return the resource in flavor of an URL
. So when having an OutputStream
, you should really be writing it to a (temp) file so that you can get an URL
out of it.
E.g.
<ui:include src="/dynamic.xhtml" />
with
public class DynamicResourceHandler extends ResourceHandlerWrapper {
private ResourceHandler wrapped;
public DynamicResourceHandler(ResourceHandler wrapped) {
this.wrapped = wrapped;
}
@Override
public ViewResource createViewResource(FacesContext context, String resourceName) {
if (resourceName.equals("/dynamic.xhtml")) {
try {
File file = File.createTempFile("dynamic-", ".xhtml");
try (Writer writer = new FileWriter(file)) {
writer
.append("<ui:composition")
.append(" xmlns:ui='http://java.sun.com/jsf/facelets'")
.append(" xmlns:h='http://java.sun.com/jsf/html'")
.append(">")
.append("<p>Hello from a dynamic include!</p>")
.append("<p>The below should render as a real input field:</p>")
.append("<p><h:inputText /></p>")
.append("</ui:composition>");
}
final URL url = file.toURI().toURL();
return new ViewResource(){
@Override
public URL getURL() {
return url;
}
};
}
catch (IOException e) {
throw new FacesException(e);
}
}
return super.createViewResource(context, resourceName);
}
@Override
public ResourceHandler getWrapped() {
return wrapped;
}
}
(warning: basic kickoff example! this creates a new temp file on every request, a reuse/cache system should be invented on your own)
which is registered in faces-config.xml
as follows
<application>
<resource-handler>com.example.DynamicResourceHandler</resource-handler>
</application>
Note: all of above is JSF 2.2 targeted. For JSF 2.0/2.1 users stumbling upon this answer, you should use ResourceResolver
instead for which an example is available in this answer: Obtaining Facelets templates/files from an external filesystem or database. Important note: ResourceResolver
is deprecated in JSF 2.2 in favor of ResourceHandler#createViewResource()
.
My solution for JSF 2.2 and custom URLStream Handler
public class DatabaseResourceHandlerWrapper extends ResourceHandlerWrapper {
private ResourceHandler wrapped;
@Inject
UserSessionBean userBeean;
public DatabaseResourceHandlerWrapper(ResourceHandler wrapped) {
this.wrapped = wrapped;
}
@Override
public Resource createResource(String resourceName, String libraryName) {
return super.createResource(resourceName, libraryName); //To change body of generated methods, choose Tools | Templates.
}
@Override
public ViewResource createViewResource(FacesContext context, String resourceName) {
if (resourceName.startsWith("/dynamic.xhtml?")) {
try {
String query = resourceName.substring("/dynamic.xhtml?".length());
Map<String, String> params = splitQuery(query);
//do some query to get content
String content = "<ui:composition"
+ " xmlns='http://www.w3.org/1999/xhtml' xmlns:ui='http://java.sun.com/jsf/facelets'"
+ " xmlns:h='http://java.sun.com/jsf/html'> MY CONTENT"
+ "</ui:composition>";
final URL url = new URL(null, "string://helloworld", new MyCustomHandler(content));
return new ViewResource() {
@Override
public URL getURL() {
return url;
}
};
} catch (IOException e) {
throw new FacesException(e);
}
}
return super.createViewResource(context, resourceName);
}
public static Map<String, String> splitQuery(String query) throws UnsupportedEncodingException {
Map<String, String> params = new LinkedHashMap<>();
String[] pairs = query.split("&");
for (String pair : pairs) {
int idx = pair.indexOf("=");
params.put(URLDecoder.decode(pair.substring(0, idx), "UTF-8"), URLDecoder.decode(pair.substring(idx + 1), "UTF-8"));
}
return params;
}
@Override
public ResourceHandler getWrapped() {
return wrapped;
}
static class MyCustomHandler extends URLStreamHandler {
private String content;
public MyCustomHandler(String content) {
this.content = content;
}
@Override
protected URLConnection openConnection(URL u) throws IOException {
return new UserURLConnection(u, content);
}
private static class UserURLConnection extends URLConnection {
private String content;
public UserURLConnection(URL url, String content) {
super(url);
this.content = content;
}
@Override
public void connect() throws IOException {
}
@Override
public InputStream getInputStream() throws IOException {
return new ByteArrayInputStream(content.getBytes("UTF-8"));
}
}
}
}
来源:https://stackoverflow.com/questions/20268860/include-dynamic-content-containing-jsf-tags-components-from-stream