Lagom by default uses Google Guice as implementation od DI pattern.
I would like to use Spring Framework instead.
Is it possible? IF so, how should it be done?
I have successfully integrated Akka with Spring (using hints from documentation and Internet), however I cannot find anything in documentation about integrating with Spring.
Possible? Yes. Will you be constantly swimming upstream, with reach upgrade break in new and unexpected ways requiring you to debug undocumented internal APIs? Most probably.
Lagom is built on Play, Play's DI support is ostensibly pluggable, when I wrote it I hacked together a proof of concept to ensure that Spring could be plugged into it. But it was only ever a proof of concept, neither I or the Play team ever had any desire or intention of maintaining it, so I published my work to GitHub:
https://github.com/jroper/play-spring
So that anyone for whom Spring support was important could continue where I left off. That was 3 years ago. In spite of a community of over a hundred thousand developers, no one ever took the work up. There's not a lot of work to do on the module itself, where most of the work would be is in Play and Lagom to fix areas where they have grown incompatible with Spring.
But really, why do you want to use Spring? The whole Lagom and Play ecosystems are built on Guice, saying you want to use Spring with Lagom is like saying you want to use a narrow gauge train in a country that only has standard guage rails, you're going to have to build yourself an entire new rail system to do so. What do you hope to achieve?
Related
I'm thinking about adding GraphQL functionalities to my Spring Boot application.
I found there are two artifacts for that.
One is com.graphql-java-kickstart:graphql-spring-boot-starter and the other is com.graphql-java:graphql-spring-boot-starter.
Which one should I choose?
These are different Starters (by different teams) providing different features, so there's no right or wrong answer. Here's a quick overview of what I'm aware is available:
The original starter made by the graphql-java team (com.graphql-java:graphql-spring-boot-starter) is now, I believe, defunct and superseded by the Spring GraphQL.
Spring GraphQL (org.springframework.boot:spring-boot-starter-web or org.springframework.boot:spring-boot-starter-webflux) is intended for schema-first development, is relatively simple and not very feature rich, but it's easy to use and works well with other Spring projects (like e.g. WebFlux and Spring Security).
If you want to go code-first (which I argue is still schema-first, just better), use graphql-spqr-spring-boot-starter, which will generate the GraphQL schema and an end-point for you, with no extra code needed. It's quickest way possible to expose Spring services. There's a sample project here. I'm the main author of that project, so this is a shameless plug, but I honestly believe it's lightyears ahead of other projects in terms of usability. The next version will be based on Spring GraphQL, so it should inherit most/all benefits as well (like e.g. RSocket support, which it currently lacks).
There's also DGS by Netflix (com.netflix.graphql.dgs:graphql-dgs-spring-boot-starter). It is also schema-first, has a plenty of features, but is also highly opinionated. I have no first-hand experience with it, but it is well documented, so you should have no problems finding what you need about it.
If you're already using graphql-java-tools (maintained by the Kickstart team), you'll likely want to go for com.graphql-java-kickstart:graphql-spring-boot-starter as they're intended to be used together. I have no clue how actively this project is maintained these days.
I was thrown into a CXF-based project in which the basic HowTo tutorials are easy to follow and implement but the moment there is a problem or a bug in the system, all kinds of exceptions are thrown without me understanding any of the relationship between the various components.
I know that CXF builds on top of Spring.
But I have no experience with Spring and I don't know how it works.
I have also seen references to JAXWS in the cxf.xml but I don't know how it is related to either Spring or CXF.
I can build a perfectly working (simple) CXF-based web service. Contract first, using wsdl2java in a pom.xml (copycatting a sample).
But the moment I face a problem, I am stumped, relying on some tips and clues gleaned from the web.
Ideally, I would like to have a tutorial that walks me through the history of how web services evolved from Java only, to J2EE, to JAXWS, to Spring, to CXF.
But I couldn't find any.
I did find the official Apache CXF documentation but it assumes a lot of prior knowledge that is more than just knowing the Java language.
Any recommendations on how to get to a point of truly understanding what I am doing when I build a web service?
A recommended book? Online tutorial?
Thanks.
Yip it is a bit of a learning curve but well worth it. As far as books are concerned you can try the following.
Apache CXF Web Service Development
Spring In Action
Please be aware that J2EE and Spring are not evolutionary linked to each other Spring was more a reaction to the heavy weight J2EE specification of old. CXF is a web services toolkit/API that can be used outside of J2EE as well.
I would suggest you also join the user lists of the CXF projects and ask questions there. Also why not post some of the code causing exceptions here so we can help you with more detail?
I know the title may seem like apples & oranges, but hear me out... :)
I'm building the architecture of an MVC app and considering what to use for the core of the controller / services. This stack will also serve as a RESTful API which will be equally as important as the UI.
I'm narrowing down my stack to be built with either Grails or JAX-RS (at this point I've ruled out other options and am not super interested in expanding this list). Either way I'll be using Groovy, and my model and views will be virtually unaffected by this choice, so that further levels some of the differences between the two. Here are the pros/cons that I've been pondering and was wondering if anyone had any other inputs or caveat experiences.
Grails
I am not going to use a ton of the built-in Grails features (GSP/SiteMesh, Hibernate, nearly all plugins), so I'm concerned that Grails might be a bit heavy for my purposes
I'm concerned that I won't have enough control over my ability to handle the REST API since it is very view-centric
I've seen inconsistencies in the quality of plugins to the point where I'm not sure I consider them much of a 'pro'
I love the convention-over-configuration & edit-and-refresh, to the point where I'd probably want to wire up something similar if I go with JAX-RS
I like the grails command line for everything it streamlines, but I'm concerned that it might get in my way since I'm not using as much of the stack
I like the scaffolding but since I'm not using Hibernate or GSP/SiteMesh it might not mesh well
JAX-RS
JAX-RS is made for REST. This will make my RESTful API really a snap to implement as I have complete control
Groovy is an important part of what makes Grails shine, so I'll benefit from that even in JAX-RS
I love how JAX-RS doesn't automatically pull in a bunch of other things so I can have more control of what components are in/out
unfortunately since it doesn't pull in everything else anything that I end up needing will require more work, whereas Grails might have a plugin
the grails command line and scaffolding will be missed; perhaps Maven can fill some gaps
It seems like the capabilities of each for creating actions and routing are pretty similar (although the implementation styles are different). In fact there are other SO questions wish touch upon this so I'm not too concerned.
I wrote a small REST service prototype in several frameworks last year (namely Grails, Play!, Spring MVC, Jersey, Restlet). My feeling about Grails in this concern was that although Grails supports REST style architecture, it isn't really made for it. I don't want to get religious here, so if you only want to map resources to URLs and HTTP verbs your fine, but if you want to dig deeper into REST with tight control over return codes, location headers, etc. you might still be able to do it with Grails, but it is probably better supported in a pure REST framework.
Grails also comes with a lot of dependencies, which might not be a problem if you're starting on a green field, but can cause problems when you have to integrate it with existing legacy components or frameworks.
From the two used REST frameworks, I liked Jersey more, as it just worked in my case and the documentation was good (although a bit focused on Maven and Netbeans).
Yeah, it does seem heavy to build on a MVC framework when you're not going to use the model or the view. While the autowiring and simplified configuration is super nice, Grails would still be providing a lot of extra stuff that you don't need.
I'd personally take the lighter approach and leave Grails out, using any standalone libraries or writing custom code which provide the features that you do want. There's a number of container projects listed on the Groovy site, perhaps Spring or one of the alternatives would add some value to your architecture.
I am just starting to learn about spring and was looking at the difference between Spring 3.0 and Spring 2.5.
Initially i was following this tutorial http://static.springsource.org/docs/Spring-MVC-step-by-step/index.html which is a step by step guide to developing a Spring MVC application. It is based on Spring 2.5 and i notice there are quite a few differences with Spring 3.0. I tried to find the equivalent tutorial that is based on 3.0 but couldnt find it.
The difference i notice with 3.0 is that there is a lot of use of annotations and a lot of things is done for you in the background. I am sure this is a good thing but i am wondering for the purpose of learning the framework should i continue with 2.5 so that i can understand what goes on behind the scenes before i use spring 3.0?
Please also if you can recommend a spring book that is suitable for a beginner i would appreciate it.
Thanks
I'd recommend to always use the latest version of a framework. Especially if you're starting on a new project. There are always (well usually) tons of improvements, and simplifications, and migrating to the latest version later may be a pain.
Spring has a great user manual (see http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/), and IMHO a book doesn't have an added value in this case. I found the Spring user manual always easy to read and understand, so don't get intimidated. I think this is definitely the best starting for beginners as well. You don't have to read it all. Only the sections of interest!
Note that Spring 3.x contains many other improvements such as SpEL (Spring Expression Language), improved web support (you already saw that), REST support, and more.
... should i continue with 2.5 so that i can understand what goes on behind the scenes before i use spring 3.0?
That's really up to you to decide, but if you are going down the Spring 3.x annotation-based route, it is not clear that you >>need<< to understand what is happening behind the scenes. Especially for run-of-the-mill applications.
I was not aware of the purchase of Spring by VMware. Do you think this might affect the open source aspect of Spring in that it might not be open source anymore?
First, the SpringFramework guys are thoroughly committed to open source (from what I can see). So a change would probably entail lots of developers leaving.
Second, most of the people who use Spring do so because it is open source, so a change would risk a major migration of (paying) customers away.
Third, turning Spring into a closed source product would be a politically awful move for VMware, and would likely have fallout for other VMware product lines.
Finally, and most importantly for people committed to using Spring: there is no way that the VMware could legally "undo" the open sourcing of current Spring releases. The best they could do would be say that Spring 4.0 etc was closed source. Anyone who wanted to would be free to continue distributing and using SpringFramework 1.0.x, 2.0.x, 2.5.x, 3.0.x and all associated open sourced technologies. And anyone would be free to create a "fork" of any of them to continue Spring open source development. The only possible issue would be the use of trademarks, and that is easily worked around.
Add that all up, and (IMO) there is nothing to worry about.
"Spring in Action", "Pro Spring", and "Spring Recipes" are the three that I'd recommend to anyone.
If you've never used Spring, I'd say that learning either one will suit your purposes. The majority of Spring 2.5 carries over to 3.0, so it's not wasted.
The books and tutorials haven't kept up with Spring 3.0. Another change between versions was the purchase of Spring by VMWare. They've separated paid support from open source, so it's hard to tell what the future will be for non-paying customers.
I have looked at Spring MVC a few times briefly, and got the basic ideas. However whenever I look closely it seems to require you already know a whole load of 'core Spring'. The book I have for instance has a few hundred pages before it gets onto Spring MVC... which seems a lot to wade through. I'm used to being able to jump in, but there's so much bean-related stuff and XML, it just looks like a mass of data to consume.
Does it simplify if you put the time in, or is Spring just a much bigger framework than I thought? is it possible to learn this side of it in isolation?
#John Spring just a much bigger framework than I thought? - probably so, at least I thought so.
is it possible to learn this side of it in isolation? - Yes , here is a good way to learn your way http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/spring-web.html
And also I'd recommend you read a book manning spring in action 2nd edition, I also was learning spring from zero, and now I'm comfortable with it after reading this book, of course you have to refer to reference every now and then.
Here is where you can get basic info about MVC concept if you are not already familiar with(its in php, but important thing is point not syntax)
http://net.tutsplus.com/tutorials/other/mvc-for-noobs/
EDIT
If you want to see MVC in action, with examples or other spring uses use this repository https://src.springframework.org/svn/spring-samples to checkout some projects , you'll see mvc-basic, mvc-ajax ..etc this is really good resource , you can checkout projects with Tortoise SVN on windows or subeclipse from eclipse
At least you need to understand the core Spring - dependency injection, application context configuration and so on. It's actually not too complex, just a bit hard to start. For an experienced developer it might make sense to take a look at some sample app for the basic setup.
ps. I've got this sample project for JSF/Spring/JPA/Hibernate combination. Not Spring-MVC, but may be still helpful.
I myself am trying to learn Spring MVC from NetBeans official documentation from here:
http://netbeans.org/kb/docs/web/quickstart-webapps-spring.html
Coming from ASP.Net/C#, it feels like there are so many steps to do in that simple example.
The great thing about Spring is that you can pick and choose what you use. If you want to use Spring, you don't have to jump in head first, you can just try it out by, say, using the Dependency Injection features, or by using the JDBC Template stuff. My recommendation would be to start small, and see how you like it.
To use the Web MVC stuff, you will need to understand Dependency Injection for configuring your controllers. You can choose to use the older more flexible XML-style configuration, or you can use the newer Annotations. Or you can mix and match. Starting with XML would probably be best as it will help you understand how stuff is working (it'd be like learning C and C++ before Java). Then you can move to using Annotations. Personally, I use XML to instantiate all my beans. I use the #Autowire annotation to inject dependencies. This seems to be the sweet spot for most flexibility and ease of use.