Add attributes to the model of all controllers in Spring 3

You could write an org.springframework.web.servlet.HandlerInterceptor. (or its convenience subclass HandlerInterceptorAdapter)

@See: Spring Reference chapter:
15.4.1 Intercepting requests – the HandlerInterceptor interface

It has the method:

void postHandle(HttpServletRequest request,
                HttpServletResponse response,
                Object handler,
                ModelAndView modelAndView) throws Exception;

This method is invoked after the controller is done and before the view is rendered. So you can use it, to add some properties to the ModelMap

An example:

/**
 * Add the current version under name {@link #VERSION_MODEL_ATTRIBUTE_NAME}
 * to each model. 
 * @author Ralph
 */
public class VersionAddingHandlerInterceptor extends HandlerInterceptorAdapter {

    /**
     * The name under which the version is added to the model map.
     */
    public static final String VERSION_MODEL_ATTRIBUTE_NAME =
                "VersionAddingHandlerInterceptor_version";

    /**        
     *  it is my personal implmentation 
     *  I wanted to demonstrate something usefull
     */
    private VersionService versionService;

    public VersionAddingHandlerInterceptor(final VersionService versionService) {
        this.versionService = versionService;
    }

    @Override
    public void postHandle(final HttpServletRequest request,
            final HttpServletResponse response, final Object handler,
            final ModelAndView modelAndView) throws Exception {

        if (modelAndView != null) {
            modelAndView.getModelMap().
                  addAttribute(VERSION_MODEL_ATTRIBUTE_NAME,
                               versionService.getVersion());
        }
    }
}

webmvc-config.xml

<mvc:interceptors>
    <bean class="demo.VersionAddingHandlerInterceptor" autowire="constructor" />
</mvc:interceptors>