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{span:style=font-size:2em;font-weight:bold} JAX-RS : Redirection {span}

{toc}

h1. With RequestDispatcherProvider

[RequestDispatcherProvider|http://svn.apache.org/repos/asf/cxf/trunk/rt/frontend/jaxrs/src/main/java/org/apache/cxf/jaxrs/provider/RequestDispatcherProvider.java] is a JAXRS MessageBodyWriter which can redirect to JSP pages, named or default servlets. It can be used to serve all the responses from a given resource class or restricted to serving a limited set of classes only using a classResources map property. Note that this classResources property can also be used

Starting from CXF 2.5.0 and 2.4.4 it is also possible to specify thethat nameonly ofresponses theto keyrequests whichwith JSPmatching pages or other downstream servletsURIs that will use to access a response objectbe processed.

At the moment, this provider is statically configured to support text/html content types, but it can be easily configured to support other content types if needed.  

Please see this [beans.xml|http://svn.apache.org/repos/asf/cxf/trunk/systests/jaxrs/src/test/resources/jaxrs_dispatch/WEB-INF/beans.xml]. As you can see, it is possible to redirect to either to static resources such as book.html (possibly for providing some default response) or dynamic resources such as JSP pages. It is also possible to redirect to named servlets. 

Note that the only required property is a 'requestPath' one and its value should start with a forward slash but it does not have to point to an existing web application resource such as book.html; it can also have values like "/other/services/", possibly in a combination with a 'dispatcherName' property.

Finally, a servletContextPathHere are some examples. Lets assume we have a book.war web application deployed.

{code:xml}
<jaxrs:server id="bookservice1" address="/bookstore1">
    <jaxrs:serviceBeans>
      <bean class="org.apache.cxf.systest.jaxrs.BookStoreDispatch"/>
    </jaxrs:serviceBeans>		  
    <jaxrs:providers>
       <ref bean="dispatchProvider1"/>
    </jaxrs:providers> 
</jaxrs:server>

<bean id="dispatchProvider1" class="org.apache.cxf.jaxrs.provider.RequestDispatcherProvider">
      <property name="resourcePath" value="/book.html"/>
</bean>

{code}

The above redirects the response to a default book.html page which is available directly in the /webapps/book folder. Typically one would do it to return some static confirmation to the client. For example, consider a POST form request that has been processed by a given JAX-RS method and the only thing that needs to be done now is to return the HTML confirmation view. Note that JAX-RS MessageBodyWriters are not invoked if the resource method returns no custom object - which is not needed in the case of the static confirmation, so for RequestDispatcherProvider be able to redirect to book.html one should simply introduce say an EmptyConfirmation bean with no properties and return it from the resource method.

Here is another example (omitting jaxrs:server declaration for brewity):

{code:xml}

<bean id="dispatchProvider1" class="org.apache.cxf.jaxrs.provider.RequestDispatcherProvider">
      <property name="resourcePath" value="/book.jsp"/>
</bean>

{code}

The only difference from the previous example is that "/book.jsp" will be delegated to with the task of creating a view. This is a more interesting example and we presume that the resource method returns say an instance of the "org.bar.Book" bean:

{code:java}
@Path("/books")
public Resource {
    @GET
    @Produces({"text/html", "application/xml"})
    @Path("{id}")
    public Book getBook(@PathParam("id") String id) {
        // return the book
    }
}
{code}

RequestDispatcherProvider will make an instance of Book available as an HttpServletRequest attribute named "org.bar.Book" by default. this can be customized. If a "beanName" property is set, for example to "book", then book.jsp will access a Book instance as a "book" attribute. If you have say 2 resource methods returning instances of different bean classes, possibly for different view handlers then a beanNames map property can be used, for example: 

Also note how non-intrusive RequestDispatcherProvider is as far as writing the JAX-RS resource code is concerned, you simply list supported media types in @Produces as usual. 

Finally, a 'servletContextPath' property can be used to have some other ServletContext (as opposed to the current one) be used for RequestDispatcher look-ups. If set then the current ServletContext.getContext(servletContextPath) will be used to get the needed ServletContext.



h1. With CXFServlet

Please see the "Redirection" section on the [Servlet Transport|Servlet Transport] page.

Note that both CXFServlet and JAXRS RequestDispatcherProvider can work together effectively on executing the redirection requests as described at that page.

If you have CXFServlet listening on "/" (thus effectively catching all the requests) and also would like to use RequestDispatcher, then make sure that a 'dispatcherName' property is also set, for example :
{code:xml}
<bean id="dispatchProvider" class="org.apache.cxf.jaxrs.provider.RequestDispatcherProvider">
    <property name="dispatcherName" value="jsp"/>
    <property name="resourcePath" value="/WEB-INF/jsp/test.jsp"/>
    <property name="scope" value="request"/>
</bean> 
{code}

If resources which are redirected to can be made public (i.e, moved out of /WEB-INF) then alternative option (instead of adding a 'dispatcherName' property to RequestDispatcherProvider and still have CXFServlet listening on '/') is to configure both RequestDispatcherProvider and CXFServlet to redirect to resources such as "/jsp/test.jsp".

h1. Custom Redirection

One can borrow some of the code from RequestDispatcherProvider and do the custom redirection from CXF in interceptors or custom invokers, if you will try to do it then you will also need to set an AbstractHTTPDestination.REQUEST_REDIRECTED property with a 'true' value on a current input message.