I need to run some code when my application is deployed into a web container — and that class needs to be injectible by the Spring container.
I tried implementing ServletContextListener and registering the class as a listener, but injection wouldn't work.
What's the idiomatic way of doing this?
To make your class injectible by Spring container, you can extend SpringBeanAutowiringSupport.
Related
I have a Vaadin (v23) app deployed as a war that provides a UI to other wars running in the same Tomcat instance. I now have a need to expose a couple of public endpoints in the Vaadin app via a REST API, but all of the examples I've found assume an app built on Spring-boot, which this isn't. Is there any way of adding a simple, public API to the Vaadin app without having to resort to rebuilding it as a Spring-boot application?
I using tried spring-webmvc with #RestController and overriding startup configurations, but all attempts to navigate to the API are ignored.
Thanks for the helpful comments. I ended up doing it the old-fashioned way, via a static inner class of my MainView:
#WebServlet("/api/*")
public static class CustomFormServlet extends HttpServlet {
...
}
It's an inner class to share some things with MainView. I'm sure there's better ways, but it works and it's only to serve a couple of public endpoints.
We are using plugin architecture for one of our projects and we decided to use Spring pf4j for the same.
When we load the plugin via extensions - the application context is not able to find the beans created using #component in the plugin project- but the beans declared in #configuration classes are injected properly when we configure the plugin using register method - Is there anyway to scan and load the spring components in the plugin?
#Component in plugin is registered to main ApplicationContext via SpringExtensionFactory, make sure you set it up correctly in DefaultPluginManager correctly.
If you are going to use pf4j in SpringBoot, I would suggest you take a look sbp project. It is built upon pf4j and provides better integration with SpringBoot.
I'm currently trying to shift my existing dynamic web project to Spring boot project and it uses web.xml for servlet mapping. I understand that spring would ignore the web.xml file, what should be the correct approach for spring to use the existing web.xml? And yes, I still need to stick to using web.xml for this project.
I'm kinda new to this, please guide me through! Thanks!
I suppose that you need to stick with a web.xml because your container uses an older version of Servlet than 3.0.
Spring Boot is built on Servlet 3.0. You have to update your main class to extend SpringBootServletInitializer and override configure method, which tells spring to use its Servlet 3.0 support. Embedded containers like Tomcat need Servlet 3.0, so if you want to start your project during the development process (including JUnit tests) in embedded containers, I think, from what I know, the only way is to rewrite your web.xml to Servlet 3.0 java config. But if you really want to deploy you app in an older container, you still can by using spring-boot-legacy module. It allows you to use web.xml for older containers; only thing you have to do is to add
org.springframework.boot.legacy.context.web.SpringBootContextLoaderListener in your web.xml.
For more information about deploying war in an old container, take a look at Spring Boot's official documentation.
Spring Boot uses Servlet 3.0 APIs to initialize the ServletContext
(register Servlets etc.) so you can’t use the same application out of
the box in a Servlet 2.5 container. It is however possible to run a
Spring Boot application on an older container with some special tools.
If you include org.springframework.boot:spring-boot-legacy as a
dependency (maintained separately to the core of Spring Boot and
currently available at 1.0.2.RELEASE), all you should need to do is
create a web.xml and declare a context listener to create the
application context and your filters and servlets.
This is a very old question, but I'm currently on the same situation and I will share my experience.
I extended the SpringBootServletInitializer class to create my #SpringBootApplication, and it will INCLUDE your web.xml configuration by default. I'm still able to declare or edit existing servlet mapping, and it will be taken in account.
I have a web project, and I depoly it on tomcat easily. Infact I have a WebAppInitializer class that implements WebApplicationInitializer (this class it's really fat), as you know every application server that supports servlet 3.0, it can easily detect it and try to boot it. Now I wonder that it could be possible to use spring boot starter and without any further configuration, I pass my WebAppInitializer to it and spring boot based on my WebAppInitializer boots my project?
I just want to use the approach of spring-boot to deploy application on Tomcat and I don't want to use other spring-boot's facilities.
Yes, it's an old question. But I do not see an accepted answer and the one closest to a working one only has a link to an external resource. So here it is.
https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-embedded-container-context-initializer
28.4.2 Servlet Context Initialization
Embedded servlet containers do not directly execute the Servlet 3.0+
javax.servlet.ServletContainerInitializer interface or Spring’s
org.springframework.web.WebApplicationInitializer interface. This is
an intentional design decision intended to reduce the risk that third
party libraries designed to run inside a war may break Spring Boot
applications.
If you need to perform servlet context initialization in a Spring Boot
application, you should register a bean that implements the
org.springframework.boot.web.servlet.ServletContextInitializer
interface. The single onStartup method provides access to the
ServletContext and, if necessary, can easily be used as an adapter to
an existing WebApplicationInitializer.
Scanning for Servlets, Filters, and listeners
When using an embedded
container, automatic registration of classes annotated with
#WebServlet, #WebFilter, and #WebListener can be enabled by using
#ServletComponentScan.
[Tip] #ServletComponentScan has no effect in a standalone container,
where the container’s built-in discovery mechanisms are used instead.
I've tried it. It works
In my use case I have project containing a few dozens of webapps, designed to run on Tomcat as WAR. Lots of logics was neatly crafted into WebApplicationInitializers and it seemed there should be an easier way to reuse all this. Adding implements ServletContextInitializer to those initializers and exposing them as beans through #Configuration classes lit my webservers up with SpringBoot's embedded Tomcat.
http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-create-a-deployable-war-file describes precisely how to do it
From the Spring Boot docs:
Servlet 3.0+ applications might translate pretty easily if they already use the Spring Servlet 3.0+ initializer support classes. Normally all the code from an existing WebApplicationInitializer can be moved into a SpringBootServletInitializer. If your existing application has more than one ApplicationContext (e.g. if it uses AbstractDispatcherServletInitializer) then you might be able to squash all your context sources into a single SpringApplication. The main complication you might encounter is if that doesn’t work and you need to maintain the context hierarchy. See the entry on building a hierarchy for examples. An existing parent context that contains web-specific features will usually need to be broken up so that all the ServletContextAware components are in the child context.
So yes, it's possible but you need to convert it to SpringBootServletInitializer, which seems to be quite similar.
How can i tell a application server to call a method in my stateless ejb so that I can print some message during deployment. If I annotate the method with #PostConstruct then it is not working. I also added static block still not working. I dont want to use MBean. Also my ear does not have any web project. So I can not use any servlet and its init method to print such messages.
Server we are using is Jboss.
thanks
There is no such mechanism in EJB 3.0.
Eager / auto loading of EJB / load EJB on startup (on JBoss)