How do you have your GWT project setup? Do you have a single project for the client side and separate project for the server side? Can you share your experience with organizing projects for a GWT front end, spring backend system? I am looking to use Spring + GWT + Tomcat + Hibernate for this project.
Unless you have a really good reason to split the client and server side into multiple projects, you should go with just one project.
Otherwise, you'll need your server-side project to be dependent on your client-side project since any data objects that are shared will need to be part of the client (so gwt can create a javascript version of them). This intuitively strikes me as backward.
Alternatively, you could create 3 projects; one server, one client, and one with all the shared classes. But doing that will give you two projects that gwt has to compile which you'll then have to wire back together. Unless you have to deal with some weird gwt-based legacy code integration issue, I can't see what this would get you.
Of the two significant gwt-based projects I've worked on (using the same technology stack you refer to), I have used a single project.
I use a single project for a GWT client and Tomcat backend and it works great. I love the convenience of making a quick change in protocol to both sides and then having a single build step.
The war directory in a GWT project can do all of the non-GWT stuff you're used to, with arbitrary directories and files, so it's really convenient to mix JSP, HTML, and normal JavaScript right in with GWT.
Related
I like Dart, I have been playing with it for a while. I'd like to integrate with my Maven web app project based on Spring Boot.
I suppose the correct way is to use dart-maven-plugin. But I'm not sure how to properly glue it in place. Spring Boot has its own structure, Maven as well and Dart makes that none the better.
I will need probably the entry point for Dart part, means Spring Boot templates folder needs to include the html resources from Dart.
I would appreciate any idea, best practices.
PS: the aforementioned dart-maven-plugin is not really vivid, should I be afraid using it at all, as I don't see any progress there, compared to Dart itself.
UPDATE
So this can be solution(note I have only one so called "entry point"- .dart file so far)
normal Dart structure in src/main/dart
user dart-maven-plugin's pub build command into ${project.build.directory}/dart
maven-resources-plugin:copy-resources from ${project.build.directory}/dart/web to ${project.build.directory}/classes/public/
make war
I'm still able to use Intellij's Dart integration from src/main/dart.
The Spring Boot maps classes/public/ folder to / so the dart file and html files are loaded properly.
It's not ideal, but it works so far. Please fell free to write down any comments.
I have tried a few times to use dart in a maven project myself and always ran into some problems. Right now I'm developing my dart apps in a separate module that I build with pub which connects to the maven based java backends with rest.
This has several advantages for me, for example:
I can use pub and avoid problems with outdated maven plugins
I use the serving mechanism that fits best for the static dart code and assets (in my case a docker image with nginx)
I have a clean separation of backend and frontend code with a tailored REST API
As I like the microservice approach I also use spring session together with zuul (via spring-cloud).
If you want to combine dart with generated html from for example JSPs or another templating engine, then this isn't a good approach for you. But IMHO dart is not yet very well suited for these kind of architectures.
I have some years of experience with maven projects, even with multi modules ones (which has made me hate the multi modules feature of maven (so the disclaimer is now done)) and even if I really like maven there is something I cannot get a clear answer about :
What is a typical usecase of a multi module maven project ? What is the added value of such a structure compared to simple dependencies and parent pom ?
I have seen a lot of configuration of multi module projects but all of them could have clearly been addressed by creating a simple structure of dependency library living their own life as deliverables (even with a parent pom, as a separate deliverable : factorising depedencies and configuration) and I haven't found any usecase where I can clearly see an added value of the multi module structure.
I have always found that this kind of structure brings an overkilling complexity with no real benefit : where am I missing something ? (to be truly honest, I can get that some ear can benefit from this kind of structure but except from that particular usecase, any other real use and benefit ?)
Here's a real life case.
I have a multi-module project (and to your rant... I haven't seen any complications with it.) The end result is a webapp but I have different modules for api, impl, and webapp.
12 months after creating the project I find that I have to integrate with Amazon S3 using a stand-alone process run from a jar. I add a new module which depends on api/impl and write my code for the integration in the new module. I use the assembly plugin (or something like it) to create a runnable jar and now I have a war I can deploy in tomcat and a process I can deploy on another server. I have no web classes in my S3 integration process and I have no Amazon dependencies in my webapp but I can share all the stuff in api and impl.
3 months after that we decide to create a REST webapp. We want to do it as a separate app instead of just new URL mappings in the existing webapp. Simple. One more module, another webapp created as the result of the maven build with no special tinkering. Business logic is shared easily between webapp and rest-webapp and I can deploy them as needed.
The major benefit of multi modules are
one single maven command to build all your modules at once.
and the most important : maven take care of the build order for you.
configuring your CI-server is also very easy: one single jenkins job to build everything.
I already worked in a project with about 30 submodules. Sometimes, you need to change something in more than module, and running one single command and being sure that everything that need to be compiled is compiled in the correct order is a must.
EDIT
Why 30 submodules ?
Huge framework with lot's a features, lot's of developers, separation of features on a module base. It's a real life use case and the separation of the code into module was really meaningful.
I think you are correct in that most project that use multi modules, actually don't need them.
At where I work we use multimodule projects (and I think that for a good reason). We have something similar to a service oriented architecture, so each application
A client module
An interface module (which has shared objects between the client and implementation)
an implementation module
a war module
I agree that putting that implementation and war module in the same actual module would be ok, but the (arguably) benefit of this is that is very clear division between the classes that solve the problem and how the application communicates with the external world.
In previous projects that involved just a web application, I've tried to put everything in the same module, as it made testing easier, given the modules I was using.
Multi modules can help you with re-use your code.
It's one of the best benefits you'll feel in work.
Imagine if you have 3 web projects with a security layer, You'll have to copy paste your code 3 times and trying connect it with each project.
But what if you create a security module a project with a specific job.
It'll be easy to use it by injecting it to your app and then boom it works.
Also as mentioned in #ben75's answer the one maven build command and the correct order of building all your used jars. You'll think no more about which depends on another.
I find maven modules extremely useful for the following reasons:
Architecture layering and boundaries
For example, I make a maven module application-contract which contains the interfaces my presentation layer sees. So I have UI->Presenter-> application-contract <-application-impl <- infrastructure -> domain. This way, I know that my presentation/UI layer will not have access to classes from my Domain/application layers. If domain classes are not in classpath when I code in UI, I cant use them. And I like it this way (utilizing the class path restrictions). Perhaps Java 9 modules can solve this problem too, but (unfortunately) I have work with Java 8.
Running tests in one module each time
When I change code to a layer which is a module (as mentioned previously) I can run its tests only, without re-runing tests from code I did not change. This gives me speed. My presentation layer tests need ~3 seconds (for 300 tests). Every time I change code to a Presenter or whatever below application layer, I don't want my database H2 integration tests to run. Or My Image processing tests to run. Because these do IO and they are slow.
Building
Pretty much the same thing. When I change code to UI, i have only to build and deploy UI stuff (my UI is in Java).
More of a standard practice questions:
Is there any difference in deploying an app as EAR vs WAR? How do you decide? (I know WAR is just a web application may or may not have Java EE features like messaging)
Lets say I have a Spring MVC application stack with Hibernate (MySQL DB), should this be deployed as a War or EAR?
When do we need to worry about JBoss deployment descriptors, if I am not using EJBs. (Just Spring MVC). Lets assume I have JMS as well. Do we need to configure/update/create any other JBoss related config files?
When we package our application EAR/WAR, it include EVERYTHING that we need for our app. Is there a scenario where we need to keep some config / xml files outside of this archive in a specified JBoss folder?
Is it common practice to deploy directly from Eclipse or better to use Ant, etc? Advantage / Disadvantage?
Obviously, I am a newbie :-). Trying to understand this.
1.
This is not always an easy decision, but for beginners and for small projects I would say it's nearly always a WAR. The reason for using an EAR is mainly to isolate a business layer from a UI/Web layer. See this question for more details: How can one isolate logical layers of an Java EE application
2.
I might be mistaken but I think that Spring people typically prefer WARs.
3.
JBoss (vendor) specific deployment descriptors are mostly needed to configure so-called "administered objects" and security. Sometimes they can be used for extra features that are not covered by the Java EE specification (e.g. setting the web root for a WAR). Administered objects are typically data sources (connection to a database) and JMS destinations (queues and topics).
In the traditional Java EE approach these have to be created as far away from the code as possible, which typically means a system admin would create them inside the target AS using some kind of GUI or admin console. In this setup, you as developer would throw a WAR with "unresolved dependencies" over the wall, and a system admin (or "deployer") would then spend days figuring out what those unresolved dependencies should be.
If the communication is relatively good between developers and deployers, the WAR or EAR might be thrown over the wall together with a readme-file, that at least gives some insight into which resources are needed. Depending on the organization the development team might not get any access or feedback about how those "unresolved dependencies" have been resolved. E.g. a data source with a max of 5 connections may have been created, but this may be insufficient if some code does say 10 parallel queries. Without the development team knowing the exact data source configuration, some classes of runtime problems and performance issues may be relatively hard to solve.
To mitigate these problems, some vendors, for some artifacts, offer the developer to create those "unresolved dependencies" instead using proprietary deployment descriptors which are then embedded in the WAR or EAR. For simple local JMS destinations this is then in most cases the end of it, but for data sources there is a little bit more to it. Namely, there has to be a mechanism to switch between data sources for different stages such as Dev, Beta, QA, Production etc. Additionally, it's rarely a good idea to have production passwords in the source code.
If you have a simple app that you want to try out locally, stages and production passwords are not a concern. If you deploy for a (large) company it is.
In Java EE 6 you can define a data source using a standard descriptor (web.xml, ejb-jar.xml or application.xml), and in Java EE 7 you can do the same for JMS destinations. There is no standard way to configure those based on stage, but there is a glimmer of hope that Java EE 8 will address this (see e.g. JAVAEE_SPEC-19). Vendors are not universally happy with those standardized methods, and their main documentation will almost always extensibly tell you how to do those things using their proprietary tools and descriptors, and if you're lucky as a small note tell you there's a standardized way (and then sometimes downplay that or scare you by saying it's not recommended to be used in production).
4.
See answer to 3 mostly. One option to solve the problem of how to switch between stages and keep production passwords out of the WAR/EAR, is to have the full definition of said data source inside the AS (inside JBoss in your case). Every AS installation is tied to a specific server in this setup. If data sources need to be updated, removed or new ones added, you have to communicate with your operations team (if any). As said, depending on your organization this can be anything between trivial and practically impossible.
5.
When developing you most often use your IDE to do a deployment. For production you would never do that. For production you may build with Ant (or Maven) and deploy via something like Jenkins, or e.g Chef.
Check here : .war vs .ear file
If you read the preceeding response, you'd guess that "WAR" it is.
Deployment descriptor are needed to manage the modules of JBoss, if you don't have any conflict or don't need any tweaking, you won't need any deployment descriptor.
You may need to play with some JBoss file if you want to add modules to JBoss, or configure datasources, etc. Read the JBoss documentation for more info.
You can deploy from eclipse during your development phase, but as your other environments (qualification, production, test, etc) should be separeted from your developing one and that they won't have any eclipse installed on them, you should get used to manage your server from the command line and drop your war's in the right directories.
It's a short answer, but I hope it will help.
Read JBoss documentation for more info.
Just a general question on any techniques used to seperate your web application for customer specific requirements. At the moment I have one web application but I need to add new functionality for one customer thats not needed by another. I know spring 3 comes with new support for profiles but I'm just curious if anyone has had a similar problem and how they went about solving it particularly using spring mvc and maven as a build management tool
The proper way to do this would be as follows:
Have a web assembly module. This module will build a war file containing the proper features extracted into separate modules simply defined as dependencies. My advice is to have a separate web assembly project per client. This way you will keep things neat for yourself, avoid mix-ups (such as releasing features to clients who haven't paid for them) and have an overall easier maintenance.
Furthermore decide whether to do your version separation at the level of the version tag or classifier:
The version tag you can use in order to separate things in branches.
The classifier tag you can also use to separate configurations specific to your clients.
I've got a Spring MVC application and I've decided that I'd like to try using GWT for the front end. I'd like to continue using MVC as I'll also be using Spring Security and some other springy stuff.
I'm aware of the GWT-SL project, and I guess I'll use it. The documentation is light on examples unfortunately.
What I'm wondering now is.... how do I reconfigure my project so that I can use GWT? I'm assuming that I'll lose the ability to run in hosted mode, and I suppose that's ok. Do I just add the GWT and GWT-SL jars, reconfigure my web.xml, and add a package to my project for the GWT code?
I'm using Eclipse 3.4. My existing project is standard web project.
With the new version of the GWT plugin, you'd have all the benefits of the hosted mode browser without having to modify any options. The GWTHandler from the GWT-SL will take care of your rpc call mapping. However, you will have a problem with your existing domain objects structure. You will either have to put them in GWT's 'client' package, or mirror your existing domain objects to enable them to be compiled to javascript. I have been looking for a stable non-invasive framework for doing this, but have yet to find one. Gilead looks promising, but you will have to extend its classes on your domain.
I have posted a view month ago my simple project (3 classes) how to integrate GWT with existing Spring MVC application. Simple sample also provided.
Try it, it is clear and simple: http://code.google.com/p/gspring.
You won't lose hosted mode. I don't know if you're using the internal server for that - I use -noserver so I can't help you there.
Other than that, I guess the documentation is quite clear. Have you hit any specific problems?