How to use multiple ViewResolvers in Spring?

Question

I am working on a web app where I have most of my pages making use of apache tiles (2.1.2), but a few of them need to just be plain jsps.

I am having a problem in that both an InternalResourceViewResolver and a UrlBasedViewResolver will try to resolve the view no matter what, so that no matter which ordering I use, it will either fail on the plain JSP pages, or on the tiles pages.

Here is the config:

<bean id="tilesViewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver">
    <property name="viewClass" value="org.springframework.web.servlet.view.tiles2.TilesView"/>
    <property name="order" value="0"/>
</bean>

<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/"/>
    <property name="suffix" value=".jsp"/>
    <property name="order" value="1"/>
</bean>

To make it more clear what I am trying to do, I need to be able to have view states like this:

<view-state id="someState" view="/someDir/foo"><!--render foo.jsp -->
    <transition on="foo" to="bar"/>
</view-state>

<view-state id="someState" view="something.core"><!--render tile defintion named 'something.core' -->
    <transition on="foo" to="bar"/>
</view-state>

Does anyone know how to configure things so that I can get it to render tiles definitions and plain jsps?

Answer 1

It looks like you're on the right track, but the thing to bear in mind is that some view resolvers behave as if they have always resolved the view. You need to make sure to put such resolvers last in your ordering. I believe the Tiles view is one such.

Edit: whoops... yes, the other poster is correct, both of these resolvers will do 'always match' so you can't use them both in a chain. Another alterative would be to try to extend the TilesView to do a simple JSP render if it cant find a configured tile view.

Answer 2

As you say, you cannot chain these together. The javadoc for both states clearly that they must both be at the end of the resolver chain.

I suggest that if you really need to use these togather, then you write a simple custom implementation of ViewResolver which takes the view name, and decides which of your two "real" view resolvers to delegate to. This assumes that you can tell which resolver to call based on the view name.

---

So you'd define a custom ViewResolver like this:

public class MyViewResolver implements ViewResolver {

    private ViewResolver tilesResolver;
    private ViewResolver jspResolver;

    public void setJspResolver(ViewResolver jspResolver) {
        this.jspResolver = jspResolver;
    }

    public void setTilesResolver(ViewResolver tilesResolver) {
        this.tilesResolver = tilesResolver;
    }

    public View resolveViewName(String viewName, Locale locale) throws Exception {
        if (isTilesView(viewName)) {
            return tilesResolver.resolveViewName(viewName, locale);
        } else {
            return jspResolver.resolveViewName(viewName, locale);
        }
    }

    private boolean isTilesView(String viewName) {
 .....
    }
}

You'd need to implement the isTilesView method to decide which resolver to delegate to.

In the XML config, define this new view resolver, and make sure it appears before the other ones.

<bean class="MyViewResolver">
    <property name="tilesResolver" ref="tilesViewResolver"/>
    <property name="jspResolver" ref="viewResolver"/>
</bean>