Spring

Spring is a JEE application framework. One of Spring main interest is to glue several components together, taking care of configuration and dependencies between those components. It also serves as a base framework for Grails.

Web Deployment Descriptor Configuration

• Due to the breaking of request path elements by the servlet container, it seems you cannot use a directory path mapping to Spring dispatcher servlet. Something like "/spring/*" is apparently not supported, since the servlet path is not what is expected by the dispatcher. Look here for more information.

• A recommended configuration is either to use extension mapping (*.html) or map everything to the SpringDispatcher by using the "/" mapping. This prevents the use of the default servlet though, so be careful.

Configuring Beans

Hibernate session factory & Data Sources

• The class to use to configure an Hibernate session factory is org.springframework.orm.hibernate3.LocalSessionFactoryBean. If you use Hibernate annotations, you must set configurationClass to "org.hibernate.cfg.AnnotationConfiguration". You can also use a subclass of LocalSessionFactoryBean to configure annotated classes (which allows you to not use an XML file at all, but configure everything through Spring).

• The data source can of course be configured with Hibernate XML configuration, but it is recommended to configure it as a Spring bean and set the session factory dataSource property to it. This allows any Spring configured data source object to be used, not only Hibernate connection providers.

Transaction Support

• It's important to be aware than for Spring managed transactions, rollback occur only if an unchecked exception is thrown. If a checked exception is thrown, the transaction does not rollback.

Locale Support

• Spring supports different mechanisms for determining the current locale (the locale associated to the current thread). Grails uses the cookie mechanism (with a fallback to the HTTP request Accept-Language header).

Obtaining the current HTTPServletRequest

• Obtaining this object in a domain object should generally considered as a bad practice, as it couples the object to an HTTP request. However this can be done using the following code (this works at least in Grails):

import org.springframework.web.context.request.RequestContextHolder as RCH
def request = RCH.currentRequestAttributes().currentRequest

Data Binding

• Spring supports custom data binding for certain classes through the use of PropertyEditors.