Where do Spring configuration files go in a maven WAR module?

Question

I've looked at a bunch of sample project and I can't seem to tease out a common best practice. I've seen Spring bean files sometimes go in the web-app/WEB-INF directory. I've seen this in conjunction with with a servlet definition in web.xml like this:

<servlet>
    <servlet-name>my-stuff</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/my-stuff-servlet.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

But I've also seen bean config files included within web.xml top level -- i.e. outside of a servlet. What does this mean? Is this for cross-servlet beans? Sometimes it's in the web-app/WEB-INF directory and sometimes its in src/main/resources. Also I've seen other bean files defined in WAR modules with just about everything in src/main/resources.

I've read and re-read the Spring documentation, but the only convention I found is that by default a servlets context config file should be in the web-app/WEB-INF directory named {servlet-name}-servlet.xml.

So what's the best practice and why?

Answer 1

Application contexts in Spring can form hierarchies where child context has access to beans defined in parent context.

A typical Spring MVC web application contains a hierarchy with two levels:

• Root web application context loaded by ContextLoaderListener. Config location of this context is applicationContext.xml by default and can be configured using <context-param> named contextConfigLocation, i.e. at the top level of web.xml. This context usually contains a core application logic.

• Servlet-specifc context loaded by DispatcherServlet. Its config location is by default <servletname>-servlet.xml and can be configured using <init-param> named contextConfigLocation, i.e. at servlet level. This context usually contains a Spring MVC-related stuff (controllers, etc) since DispatcherServlet is a part of Spring MVC.

The latter context is a child of the former.

If web application doesn't use Spring MVC as a presentation framework, it doesn't have DispatcherServlet and its context. Some extremely simple Spring MVC samples doesn't have ContextLoaderListener and the root context (however, you need root context for cross-servlet functionality such as Spring Security).

Config files of web application are by default located in webapp's root folder. However, they can be placed in the classpath (i.e. in src/main/webapp), in this case they are accessed via classpath: prefix. This may be useful if you are going to use some of these files in integration tests without servlet container. Also classpath: prefix may be useful when you want to load a config file from a separate artifact, i.e. from a jar file in /WEB-INF/lib.