Spring 2.5 managed servlets: howto?

Correct me if anything is wrong.

As I understand, all Spring functionality, namely DI works when beans are got thru

Spring Context, ie getBean() method.

Otherwise, none can work, even if my method is marked @Transactional and I will

create the owning class with a new operator, no transaction management will be provided.

I use Tomcat 6 as a servlet container.

So, my question is: how to make Servlet methods managed by Spring framework.

The issue here is that I use a framework, and its servlets extend the functionality of

basic java Servlets, so they have more methods. Still, web.xml is present in an app as usual.

The thing is that I do not control the servlets creation flow, I can only override a few methods

of each servlet, the flow is basically written down in some xml file, but I control this process

using a graphical gui.

So, basically, I only add some code to a few methods of each Servlet.

How to make those methods managed by Spring framework? The basic thing I need to do is

making these methods transactional (@Transactional).

comment to Bozho: @Bozho Let's see.

In these servlets' methods I work with framework capabilities, let's say special variables that are got and saved in the current session.

And what is needed, is looping through those framework-based collections while saving some values in a database.

What you suggest is introducing a new very complex object, so that it could be passed to a service layer. (Service layer will not know anything about framework, its classes and objects kept in current Session!

First, we "wrap" framework based collections to such a object, so copy everything into it.

Then, again, the Service layer method should e开发者_Go百科ither save changes in a database or, worse case, return a new complex object so that Servlet framework method could update framework variables depending on the result of Service layer method execution.

It is a workaround but do you think it is a good idea?

You can also define your servlets directly in the Spring application context. You'll need a "proxy" servlet registered in web.xml and delegating to the servlet instance which is configured as bean in the applicationContext.xml. Proxy servlet is configured with the name of the target servlet bean, it discovers this bean via WebApplicationContextUtils.getRequiredWebApplicationContext().getBean(...) and delegates all the processing to the target servlet. In this case an instance of your servlet is completely managed by Spring.

I'd suggest restructuring your code - making servlet methods transactional is not a good thing to do. Put the transactional logic in a separate, service class, and either

• obtain these spring-managed classes by WebApplicationContextUtils.getRequiredWebApplicationContext().getBean(..) or
• in your servlet init() method obtain the ApplicationContext with the above method and call appCtx.getAutowireCapableBeanFactory().autowireBean(this). This way you can inject the transactional classes in your servlet as if it was spring-managed.

Now, you can do all this, but it is definitely not a beautiful way to go. I'd suggest using Spring MVC or any other MVC framework (which support spring integration of its components)

If this is all not possible, as a last resort I think you can use @Configurable (on your servlets) with a <context:load-time-weaver/>.

You should take a look how Spring proxy filters: http://grepcode.com/file/repository.springsource.com/org.springframework/org.springframework.web/3.0.2/org/springframework/web/filter/DelegatingFilterProxy.java

In theory you could easily make the same sort of proxy for servlets and DispatcherServlet is sort of a proxy.