Migrating an existing spring jersey servlet2.5, Jersey2.3 webapp to springboot - spring

Evaluating to port an existing mid to large sized multi module JEE application, this consists servlet 2.5, Jersey for rest and Spring 3.2.9 (JDK8, Maven 3. currently we build a war file and deploy it on to aws. My objective for this exercise is to be able to use spring-boot to create a self contained executable jar that can be installed on AWS and this would help us just run on cloud with java -jar
Is it possible to use spring boot considering the project is not using spring-web module, it is more traditional Servlet2.5 statically declaring all servlets and filters in web.xml
which approach is better, adding spring boot as a parent or dependency.
Any experience and info our senior spring community members have in this kind of migration.

This is absolutely possible to do even if you're not using Spring Web MVC.
You can use spring-boot-starter-parent like a BOM POM, so you can import its dependencies without having to change your POM's parent.
Take a look at the Spring Boot documentation for migrating a web.xml application to Spring Boot. The main points here for traditionally deployed servlets and filters are:
A #Bean of type Servlet or ServletRegistrationBean installs that bean
in the container as if it was a <servlet/> and <servlet-mapping/> in
web.xml.
A #Bean of type Filter or FilterRegistrationBean behaves
similarly (like a <filter/> and <filter-mapping/>.

Related

Spring boot - unable to use web.xml with WAR deployment

I am not able to use web.xml with spring boot in war deployment.
I am aware that there are ways of converting web.xml using #Configuration, but I must stick with web.xml for now. I was following the official document, here: http://docs.spring.io/spring-boot/docs/current/reference/html/howto-traditional-deployment.html#howto-create-a-deployable-war-file-for-older-containers
I was able to deploy my application in WAR file, but it was not using web.xml.
Maybe I am not following the step 85.2 correctly, as I am not sure what it means by "load an applicationContext via a DispatcherServlet":
85.2 Create a deployable war file for older servlet containers
Older Servlet containers don’t have support for the
ServletContextInitializer bootstrap process used in Servlet 3.0. You
can still use Spring and Spring Boot in these containers but you are
going to need to add a web.xml to your application and configure it to
load an ApplicationContext via a DispatcherServlet.
Can you guide me or point me to any examples or working sample project using web.xml in spring boot? I am using weblogic server.

Force Spring Boot to use servlet mapping in web.xml

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.

How to set up Spring multi maven module using spring boot

I would like to evolve my Spring application with a better architecture. The technologies I'm using are : spring portfolio ( spring mvc, spring test, spring Web, spring core, spring rest...)
Today I'm using packaging to structure the different layers of my application: models, services, api and of course web where I have my controllers.
I would like to know how can I use the power of spring boot to make a multi module maven architecture with an xml spring configuration for a Web application. I read that spring boot have an embedded tomcat and since I'm using eclipse with a separate tomcat server I would like to deploy my application on it and I think that this can create a problem.
I already found some links on github with this type of projects most of them are not elaboring an architecture of a Web application and use a class for spring configuration with the embedded tomcat that spring boot offers.
Thank you
Ps: sorry for my bad English
What you mean by multi module. If you want to build your jar for multiple environment you can use maven profile for it. Spring boot is nothing but a spring project which ease the configurations for you.
Regarding deployment to your own server, you have to convert the jar to war. Read "What about the Java EE Application Server" section of below link.
https://spring.io/blog/2014/03/07/deploying-spring-boot-applications

Least intrusive way to add Spring task scheduling to a non-Spring web project?

How should I add Spring task scheduling to a non-Spring war project? Currently, the web project only has a maven dependency to org.mitre.dsmiley.httpproxy:smiley-http-proxy-servlet. It's just a simple proxy servlet now. SpringBoot is probably not a good fit for this problem as I want to keep the war artifact the deployment model. I do not want to run it embedded in a stand-alone container. I'm looking for the least intrusive approach. Any suggestions?
If you are planning to deploy the app to a server that supports Servlet 3.0, then it is actually quite easy to use Spring Boot in a traditional, war deployment model.
What you need to do is:
Extend SpringBootServletInitializer, which in turn implements WebApplicationInitializer and can configure the servlet context.
Specify the war packaging in your pom.xml (which you probably already have)
Set the provided scope for the spring-boot-starter-tomcat dependency, so that an embedded server is not created when your application runs.
See the reference guide for more details.

Override Spring jar in Weblogic 12c

We have been facing an issue while overriding the Spring jar in Weblogic 12c. Basically we need to write a bean based on some 3rd party API calling their interfaces. Now they use Spring 2.5 jar for their own implementation. Since Weblogic inherently supports Spring 3.0 jar. As a result when we write our bean wrapping their interfaces and deploy it, it doesn't work. We replicated the issue by replacing Spring 2.5 jar with Spring 3 in local environment.
If we modify the server classpath to load the Spring 2.5 jar (preceding Spring 3.0), entire soa-infra application goes down, so what We wanted to know if it is possible to override the Spring jar only for our application itself? While loading the application it will override the Spring 3.0 jar with Spring 2.5 in the application context but server will keep using Spring 3.0?
Any ideas/suggestions highly appreciated!
Thanks,
Bhaskar
Try using prefer-application-packages in your weblogic.xml file.
<container-descriptor>
<prefer-application-packages>
<package-name>org.springframework</package-name>
<prefer-application-packages>
</container-descriptor>

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