I'm starting new application. I would like to have all business logic and domain classes separeted in standalone module (something like remote EJB). This is because of the app will have at least two (later more may be) clients - Desktop, Web (Spring MVC).
Is this possible with Spring? Or should I use EJB and Spring only for MVC in web app client?
Thank you for reply.
Yes, this can be done. You'll either put the resulting jar as a library in your full application, or host is separately and use some remoting system (hessian, soap, rmi, ...) to interface between them. Spring can help with that as well.
Related
I have had lots of trobule trying to get my head around how to solve this scenario:
We have an integration application that uses Camel for integration. This application also has a REST Api that exposes some services providing information about the application, for instance listing the active routes etc.
I have created a user interface for this using AngularJS that connects to these rest services. My main problem is how can I package this application as a self contained jar-file that provides the user interface and all the camel integration.
My working theory: Use a separate Jetty server to serve the Angular JS files and let Camel expose the REST services. The problem with this is CORS since the REST services reside on another port than the jetty server serving the Web UI.
Some requirements for the solution:
Must be a single self contained jar-file.
The camel integration is the main purpose, the Web UI is secondary
and only used for trouble shooting. No need for a high performance
web container since the Web ui is used by only a handful of users.
I have been struggling with this for a couple of days now and it feels like I am over complicating the solution. Help on how to solve this is greatly appreciated.
You could take a look at hawtio
http://hawt.io/
as that is how we do that, hawtio is a web console for java, and has plugins for Camel. Its built using angularjs, and uses REST to communicate with the local or remote Java JVMs. To make the REST calls easier we use Jolokia.
Jolokia requires an agent to be embedded in the JVM, eg where Camel runs. Then that helps with CORS et all. http://jolokia.org/reference/html/security.html#d0e2490
I am pretty new to spring and currently I was able to create a complete web service with spring-ws. Now I want to separate the functionalities of my web service in to two separate web services. But except the service layer there are other spring components (business layer) which are common to both of these services.
So my question is there a way to make spring web service depend on another spring project (business layer)? If you can provide such example or a tutorial where a spring web service depends on another spring project it will be really helpful.
Thanks in advance.
UPDATE
I could achieve above by building my business layer as a jar file and adding it as a dependency to the service. But now my supervisor wants me to deploy the business layer in a separate server. But I could not find any information on how to handle communication here between web service and the business layer. Any idea?
We are currently developing a web application for college and we would like some advice from a more experienced developer.
We have a backend using Hibernate to operate on a MySQL database. Another project is the web UI that uses the API delivered by the backend (registering user, fetching data associated with certain profiles etc.). We use the JSF framework (RichFaces) for the UI. Everything is built using Maven.
The technology we can't decide on is for the communication between UI and logic modules. The first option is to use ApacheCXF to provide SOAP webservices that UI can be a client of. The second option is to use EJBs to invoke backend methods from the UI module.
What approach is more widely-used? As far as we read on the Web, using EJB is faster than SOAP webservices. On the other hand, we don't have any experience with EJBs using Tomcat (we would prefer using Tomcat since it seems to be a cheaper option, however we don't know what we would have to do in order to use EJBs with Tomcat). Additionally, working with webservices since the beginning will allow us to add support for different platforms (for example, Android).
Another aspect which we are discussing is about how should the application be deployed. The alternatives we have considered right now are:
Deploy it as a single WAR project (which would solve the problem we have about communicating the UI with the backend of our application).
Deploy two WAR projects in the same server using webservices for communication between the projects. (We have a prototype using this approach deployed on a Tomcat server)
Deploy a WAR project and EJB project.
Deploy an EAR project which would contain the references to the WAR and EJB projects. (We have a prototype using this approach deployed on a Glassfish server)
The project right now is starting, so we will only be handling a couple hundreds of users right now. However, if the project succeeds we would need to deal with a couple million of users.
Any advice would be appreciated. Thanks.
Edit: So any advice about how the project should be deployed? Is it necessary to use EAR? Is there any advantage if we deploy the project as an EAR module?
Edit 2: We found the advice we needed on this thread: Deploying java applications (Tomcat/Glassfish)
First things first. I would avoid using Web Services if there's no need for it. If you feel that you might need to call this system from external programs and platforms, then go for it. Even then, I would only use the web service interface for external integration, and still have an internal EJB implementation.
EJBs are awesome for enterprise applications. I would highly recommend that you look into that. They provide support for EJB Pooling, Transactions, Aspect oriented programming, Security, Stateful sessions, Java Messaging, JNDI etc. And you can inject them directly inside a Managed Bean (JSF). You said that you will eventually handle millions of users, so I assume that you will want your application to run as fast as possible, I don't think SOAP web services will be a good fit. Remember that SOAP web services encode messages as text, so if your application will be sending binary files etc, then you'll suffer significant performance issues.
As far as deployment goes I would go with an EAR, or a WAR for the JSF and and EAR backend. you can use Injection to pull the classes you need, even remotely, from multiple web applications and other EAR apps.
I'm not sure why you say Tomcat is Cheaper. Glassfish open source edition is a fully functioning JavaEE6 Server and its free. JBoss is also JavaEE compliant and is free. both of them are used in lots of production environments. I find glassfish to be much more user friendly, and would recommend it to EJB noobs :)
I also started with Tomcat, but now I don't use it at all. why use the servlet container only, when you can have the whole shabang? hope this helps.
we use ApacheCXF at work and its has SOAP and Restful. Reliable and relatively easy to setup. I am not sure why you want to use glassfish maybe it's preference but you can implement your projects in eclipse too. It's really that is up to you and your team and the requirements and skill sets your team may have to build and support, that a side CXF webservice+apache + eclipse with maybe two war files would be a good path.
I wouldn't use web services in this case. You can use managed beans as controllers.
Put the logic into EJBs, views into rich faces and control the flow using managed beans.
If you use maven you can generate a project with the structure of EAR (war for web module and jar for ejbs). I don't remember the name of an archetype but you can find it easily.
I have an existing Java application (Spring based) that currently does NOT have a web interface, nor does it run in a web container. It packages up nicely with a start program and just works.
What I need to do is add an administrative web interface for some administrative type things, retrieving real time metrics, and perhaps some graphs to give the users a warm fuzzy feeling knowing that everything is working. As we are a Spring shop, and some of our web applications already use Spring MVC it only makes sense to us, however, I'm not happy with the suggestions I've had from our internal Spring folks on how I should procede.
What would be the ideal way to bolt on this web interface?
Convert my application to a web application and have a web container launch the application. I not too keen on this approach is the web tier is really secondary to the primary application.
Create a separate project that packages as a war, embed Jetty in my existing app and have it load the war. I think I can use the context loader listener to make the root context of my application the parent to the web application spring context. This would involve breaking up my Maven project into 2 projects I believe. I can't use an existing web technology for communication between the web tier and the primary application as my primary application is not web enabled.
Embed Jetty and put the Spring MVC stuff directly in my app. While I've done this approach before, it does involve some ugliness - for instance exploding the JSP tag libs into my jar.
Any thoughts on some clean separation here?
Also of note, my current jar contains some utility applications which some shell scripts launch. Going a pure WAR route would make this not so easy, since I can't juse point java at my war file and choose a class to execute.
Thanks.
If it's true that web is just a minor addition the application, migrating it to WAR and deploying in servlet container might be an overkill. Embedding web server/servlet container looks much simpler, although it doesn't have to be Jetty or Tomcat. You can use web server built into JDK or write one on top of netty or even raw sockets. But that's a hell to maintain.
Yet another solution to springs to mymind when reading:
web interface for some administrative type things, retrieving real time metrics, and perhaps some graphs
Maybe you don't need an interface, but monitoring infrastructure instead? Check out JMX (Spring has great support for JMX) - and write a second web application that simply connects to your standalone Java app via JMX and displays the metrics in fancy way. Another approach is to expose JMX via Jolokia, which translates JMX to REST services.
This approach has several advantages:
monitoring API is universal, and you get it for free
you don't have to use web client, monitoring application is completely decoupled,
finally changes to your original application are minimal. Check out this proof of concept: 1, 2.
It really depends on the structure of your existing Java/Spring app and how much of an API it provides. I've done something similar to this and I approached it by creating a separate Spring MVC project and then specified the existing Java app as a JAR dependency.
This is easy with Maven (or Ivy, etc) and provides nice decoupling. The trick is to be able to write service classes in the Spring MVC app which then access data via your dependent Spring app via a simple DAO class. That's why I stated at the beginning, that it depends on the structure of your original Java app. It has to be able to provide an API for data access that you can then plug your DAO (impl) into.
If this is not easily done, then the next option I'd suggest is simply converting your Spring app to a Spring MVC app. I've worked on another app where we did this. Using Maven, its possible to specify that the build can create either a war file or a jar file (or both). So it can be deployed as either a webapp (via war) or a normal app (via jar). Yes, the jar version has a bit of bloat but its a worthwhile compromise.
The question of embedding Jetty or using Tomcat via a war file is a completely separate issue that has its pros and cons. It shouldn't affect the approach you take in architecting the web app in the first place.
I'm wondering if it is possible to create XML-RPC server component within EJB module without servlets. I know EJB typically uses RMI as communication protocol but what if I want to omit RMI. What if i want to exchange data between EJB and web module (WAR) or other clients by different way like XML-RPC.
Can EJB-module work as stand-alone unit which will expose its state and services as XML-RPC server?
I still can do EJB module connected with WAR via RMI while this WAR will expose those services via servlet. Then other WARs or whatever-they-are clients can call this first WAR. Is this right or there is some other possibility?
What you probably want is to use Spring Remoting to expose your EJBs via for instance JAX-WS. Spring will create automatically servlets for handling the requests for you. The bad news is that you have to call your EJBs from the remoting services you build - meaning some boilerplate code. It should be quite straight forward though.
An other possibility you might take a look at is Restlet which can be used to build restful services.
In EJB3, your service beans are just annotated POJOs. You can simply annotate the same POJOs with #WebService (and the rest of this family of annotations) to expose the same services as web services.
I realize this isn't strictly what you asked for as the implementation for services exposed in this way is JAX-WS which uses SOAP messages. But I think it achieves your intent.