I have just returned to Spring after 5 years of gap and it seems lot is changed. I have a task to create a REST Service using Spring with hibernate as an ORM, So far I am able to run a basic Rest Service using embedded jetty and able to make GET/POST calls, the next is to integrate hibernate into it so that the data fetch/Sent operation actually use MySQL instead of sending hard-coded response(which I have done currently).
The issue is earlier I used to work on Spring MVC using Tomcat where we had web.xml to define the dispatcher servlet and application-context which in turn were used to define hibernate config and other beans declaration, but now having embedded jetty I am not finding a way to integrate hibernate to my REST app, Is the way to add configuration is changed from XML to class based config. I searched over internet but maybe I am out of words or not using correct keywords, in short, Have no luck finding some solution to integrate hibernate to my Spring app which is using embedded jetty.
Could some please breif me about the recent changes or point me to the right tutorial ?
Any help appreciated, thanks in advance !
ps - I have used this example to progress so far https://github.com/pethoalpar/SpringMvcJettyExample
Yes , lot of changes in these 5 years and one of the game-changer is spring-boot
If you want to build a brand new project especially if you want to run the web application on the embedded container such as Jetty , you can check out spring-boot.It already provides integration with Jetty , hibernate and Spring MVC REST service.
The end result is that you just need to change a little bit configuration (most probably the DB connection info) and you can quickly get a production-ready REST service backed by JPA/Hibernate which can just run without any XML configuration anymore.
There are tons of tutorials in Internet talking about how to do it . You should easily find them out such as this using the keywords something likes "springboot webservice hibernate jetty" etc.
Related
I've started learning Spring Boot coming from a NodeJS/Express background and I'm wondering what's the difference between the server that we create ourselves in an express app that listens on a certain port, and the Tomcat server in a spring application also called a container ? Why can't we do the same in a spring boot application where we create the server ourselves ?
const app = express();
app.listen(3000, () => console.log("Server listening on port 3000"));
Welcome to the Spring Ecosystem. We hope you enjoy your stay!
My first bit of advice, forget everything you know about Express because Spring is very different. I have not used Express in a while, but I remember it had a very programmatic approach. While that is possible in Spring, the most popular approach is declarative with annotations. Or, if you are old and like old technology, you can configure everything with XML.
What's Tomcat? Tomcat is a implementation of various Jakarta EE (formally Java EE) specifications. Depending on the Spring Boot version, you may see packages that start with jakarta or javax. Tomcat implements, Jakarta Servlet, Server Pages, Expression Language, WebSocket, Annotations, and Authentications. You can read more about each specification here. Note: Spring Boot by itself does not necessary use all of these modules and mostly Spring has many abstraction layers on top of them anyway, so you rarely will work with Tomcat directly. Specifically, spring-boot-starter-tomcat is the Spring module that uses Tomcat, and is most often included as a transitive dependency through spring-boot-starter-web.
Now, to answer your question...
Spring Boot Web configures Tomcat for you. You can definitely override this behavior! One basic way is through configuration properties. Anything under server.tomcat. A good IDE should autocomplete and show you the options. You can also change the address and port of the Tomcat server with server.address and server.port. Another popular property developers change is server.error.whitelabel.enabled. They set it to false and provide their own error page. Here is a great example. By the way, Baeldung offers a lot of free Spring tutorials and guides. It is a great place to get started. They also offer paid courses with certifications.
FYI, you do not have to use Tomcat. Read more here.
I am creating an internal CLI that is communicating with a PostgreSQL database and the easiness to create a no-code repository is one of the features that convince me to choose Spring data JPA.
However, I am not able to find some tutorial or GitHub repository to set up a Spring data JPA project without an entire spring boot application.
On the project https://github.com/spring-projects/spring-data-book/tree/master/jpa there is no main entry point, so the code is not runnable and by the way, it was updated 8 years ago ...
This other StackOverflow thread Spring Data JPA without Spring Boot does not help me because the guy could run his spring application on Google Cloud Platform finally (that was the cause of why he ask how to setup sping data jpa without spring boot).
I don't know how to start, if you have any ideas I will be happy to discuss with someone who is more experienced than me.
Thank you.
This might help if no more complete tutorial turns up https://docs.spring.io/spring-data/jpa/docs/1.5.0.RELEASE/reference/html/repositories.html
Look for this section
Standalone usage
You can also use the repository infrastructure outside of a Spring container, e.g. in CDI environments. You still need some Spring libraries in your classpath, but generally you can set up repositories programmatically as well. The Spring Data modules that provide repository support ship a persistence technology-specific RepositoryFactory that you can use as follows
In particular it says you can use a factory to generate repositories:
RepositoryFactorySupport factory = … // Instantiate factory here
UserRepository repository = factory.getRepository(UserRepository.class);
So adding the spring parts that contain the spring data classes may be enough for this level and if you want to have DI, too, you likely need to combine them with the respective spring dependencies and configure a regular spring application.
I have examples of both working individually, now trying to merge so that I have both capabilities / entry points.
Not surpised it is confused about the application contexts to load.
I want to know if this is even possible and if so any examples?
I know it is doable with spring boot however not wanting to move to that just yet.
I am attempting the impossible?
"Spring MVC (with embedded Jetty)" usually means an HTTP endpoint running in its own JVM (I suppose you have a main method that starts Jetty). Once you have that started, you can integrate it as any other HTTP endpoint in Spring Integration.
If you want them both to run in the same JVM, that probably means you don't want to make use of HTTP as you can invoke methods directly on your #Controllers or #Services.
Or perhaps I'm missing something here... ?
I'd go for Spring Boot. Version 1.1.6 was just released. I'm currently also migrating an "old" SI application to be based upon Spring Boot. I suggest you give http://start.spring.io a try. Migration should not be too difficult.
I want to use spring's dependency injection for now(other core functionalites later maybe) in tomcat application.
I want to set up spring 2.5.5 in tomcat7, But don't have clarity on how to do this.
Specifically I am confused because I don't know whether to use Spring MVC or use just spring in tomcat.
I found this question helpful: Tomcat with Spring, But still didn't get the whole scenario on how to setup tomcat with spring.
You can do either, using just core spring with tomcat is fine. MVC provides additional functionality.
Take a look at the spring source examples on github, and read their docs.
(BTW I thouroughy spring-MVC component - it really saves time developing webapps)
I'm currently developing a small EJB application running on IBM Websphere Application Server 7 (Java EE 5). The app mainly consists of one MDB listening for incoming MQ messages which are transformed and stored in a DB. Currently I'm using a lot of Singleton/Factories to share configurations, mappings, datasource lookups etc. But this actually leads to some very hard to test code. The solution might be using a (simple) DI framework like guice/spring to inject the different instances. The question is: Where to place the initialization/ setup code? Where is the main entry point of the application? How can I inject instances into the MDBs?
it might be worth looking at backing off from using Guice, and trying to work with the injection mechanisms already available with Java EE 5.
Regarding finding a suitable "startup point", unfortunately the EJB specification does not define a way where you can have a bean run at startup. However, the web profile of the EE spec does have one -- you can add a WAR to your application, and set a servlet listener component:
http://java.sun.com/javaee/5/docs/api/javax/servlet/ServletContextListener.html
You can set this to start whenever the application is loaded and started by the container (WebSphere). Watch out for classloader issues though.
Using Spring, you can do it via EJB3 interceptors, see http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/ejb.html#ejb-implementation-ejb3
Useful info on caveats are in the javadoc, make sure you read it: http://static.springsource.org/spring/docs/3.0.x/api/org/springframework/ejb/interceptor/SpringBeanAutowiringInterceptor.html