What are the significant differences defining spring configurations (beans and datasources) in Java using the #Configuration Annotation instead of XML config files. Matter of taste or is there more?
The most important difference between XML and Java config is that you have to recompile your java configuration if it changes.
With XML, you can (though you shouldn't, but maybe for hotfixes) just edit the file and add something, for example, a logger, a filter, other bean, etc., and just restart your application.
With Java, you would have to edit the source code, recompile either only the configuration .java files or the whole project and redeploy it.
Otherwise, it's a matter of taste. You can (or will be able to in 4.0) do everything in XML or everything in Java or mix it up.
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New to Spring Boot here, long-time Spring Framework user though.
I'm looking for a way to split my externalised configuration into multiple .properties files, for better readability and manageability.
I already saw this SO answer: having the ability to specify a list of configuration file names in spring.config.name (which, by the way, doesn't seem to be mentioned in Boot reference documentation, correct me if I'm wrong) would solve my problem perfectly, however that configuration property can be specified only via system properties or environment variables. If I try to specify it inside my application.properties file, it gets ignored. The same happens for spring.config.additional-location. I understand this happens because, when application.properties is read, it's too late to tell Spring Boot to search for different externalised configuration file names. However this is not a proper solution, because the way I split my configuration should be an "implementation detail" that the consumer of my application shouldn't be aware of, so I don't expect the consumer to specify an external parameter otherwise my application breaks out-of-the-box.
I think that a way to do this should be provided. Perhaps some import mechanism for .properties files or the ability to specify spring.config.name even in application.properties (some known and reasonable limitations would be acceptable).
The best I could find out is to use #PropertySource, but this is not profile aware: unless you use some ugly nested class hack, or you put spring.profiles.active variable in the resource name (which will break if multiple profiles have been activated), you won't get the benefit you have for application.properties profile-specific files.
I was not able to find an "official way" to do this, apart from some statements from Spring Boot devs that say that they're rather promoting the use of a single (possibly giant...) externalised configuration file. It seems like this position is not so popular, judging from the post reactions on GitHub, and IMHO it really seems to be a basic feature missing. I have been working with multiple properties files in Spring Framework (using XML configuration) for years and I never felt that having an only huge file would have been better.
If I understand it right, in Boot 1.x this was in some way possible using the location attribute of #ConfigurationProperties, which is however missing in Boot 2.x.
Any suggestion?
Have you tried with Spring Profile?
What you can do is create application-file1.properties/yml, application-file2.properties/yml and put it in config location and then add spring.profile.active=<your env profiles>,file1,file2.
It will load the files.
This profile entry can be in bootstrap.yml, or JVM args to application, in Manifest-<env>.yml in case of Pivotal Cloud Foundry. Not sure on AWS and other cloud provider.
Hope this will help.
I mean the Eclipse preference under Window|Preferences|Spring|Beans Support
"Disable Auto Config Detection".
When this option is not checked, I notice a delay when saving Java files:
Building Workspace...
Loading ...ServerApplication
or
Loading ...DaoConfig
These messages are for Spring Boot main application classes (ServerApplication) or Spring configuration classes with #ComponentScan (DaoConfig) which are located in the workspace.
This can take a few seconds, which is a bit annoying.
When I check the above preference option, I don't notice the delay for loading these classes (at least for the Spring Boot main classes).
What are the consequences of disabling Auto Config Detection, e.g. what does this option really do, what functionality do I loose? Any pointers to documentation?
Can I speed up the save process without having to disable Auto Config Detection?
In STS3, the IDE creates an internal model of your Spring application, so that it can display a nice overview of your Spring elements in the Spring Explorer view, provide content-assist in Spring XML config files and more. In order to build up this internal Spring beans model, it needs to know where to start from when building that model. You can define those entry points manually in the properties for each project: Spring -> Beans Support. That preference allows you to define Spring XML config files and/or Spring-annotated configuration classes to be used by the IDE internally to build up that model.
In addition to that there is a mechanism to detect those files (Spring XML config files and Spring Boot application configuration annotations) automatically, so that you don't need to configure them manually. But the result is the same. Those files/classes end up being configured to be used by the IDE to built this internal model.
I guess that the delay that you see comes from building this internal beans model - this is at least what the messages indicate that you mentioned.
So far for the background. You can disable that auto-config mechanism and you don't need to configure those files/classes manually. This will result in the Spring Explorer, for example, not showing anything meaningful for those projects.
As an alternative and in case you are working mostly with Spring Boot projects, I would strongly recommend to switch to the all-new Spring Tools 4 (also available as a ready-to-use Eclipse distribution). It provides a slightly different set of features and is implemented in a different way, so that it doesn't need the expensive internal bean model creation. You should give it a try. And if you are missing something that you love in STS3 that is not yet part of Spring Tools 4, let us know.
It looks, from the source code, that Katharsis-spring module will only work with spring boot.
My question then, is it possible to configure a spring project in xml and load Katharsis without spring boot?
If so, how would you need to configure katharsis in spring xml?
Has anyone done this before and willing to share an example?
Thanks.
Only work with Spring boot? That doesn't seem possible. Just #Import(KatharsisConfigV2.class) on any configuration in your code and it should work.
As for xml config: By design, if it can be done in code it can be done in config.
Try that and let me know how you make out
With version 2.8.1 of katharsis, it is quite a challege to get this configured just in xml. So I looked at the master branch of the project and found that there are going to be some new features which will make it easier to configure with spring xml. I have created a sample project here you can use as reference for configuration:
Sample Spring/Katharsis Project with XML configuration
In the sample project I added the SpringServiceDiscovery class, and modified the KatharsisBoot class to make the configuration easier. With the next release of this project, I should be able to remove these 2 classes completely, and use the classes that come with katharsis.
The beans I needed to add to my root-context.xml file were the following:
io.katharsis.spring.KatharsisFilterV2
io.katharsis.spring.ErrorHandlerFilter
com.springkatharsisxml.katharsis.boot.KatharsisBoot
io.katharsis.queryParams.QueryParamsBuilder
io.katharsis.resource.registry.ConstantServiceUrlProvider
io.katharsis.queryParams.DefaultQueryParamsParser
io.katharsis.module.CoreModule
io.katharsis.resource.field.ResourceFieldNameTransformer
io.katharsis.spring.boot.KatharsisSpringBootProperties
I also needed to expose the jackson objectMapper bean, as it's not done so by default in xml.
I also used the org.springframework.web.filter.DelegatingFilterProxy for the katharsisFilter and errorHandlerFilter.
I'm just learning Spring Security, and a lot of Spring's documentation appears to use Java-based bean configuration (as opposed to XML.) Overall, this seems to be the way a lot of their projects are going. However, portions of their documentation tend to start with Java configuration and then switch to XML config later on. I found a blurb in one document (http://docs.spring.io/spring-security/site/docs/3.2.0.RELEASE/reference/htmlsingle/) stating the following:
Spring Security’s Java Configuration does not expose every property of every object that it configures. This simplifies the configuration for a majority of users. . . . While there are good reasons to not directly expose every property, users may still need more advanced configuration options. To address this Spring Security introduces the concept of an ObjectPostProcessor which can used to modify or replace many of the Object instances created by the Java Configuration.
Can everything that can be done in XML configuration be done with Java config? Is there a definite direction that the Spring community is taking overall in terms of configuration style?
You can choose either java based or xml based configuration.Stick to one, don't mix both.But don't forget to use the annotation based configuration.You just need to annotate spring managed components with #component,#service etc.You don't need to have that bean defenition in xml or java class.
<context:annotation-config/>
<context:component-scan base-package="com.package"/>
or
#Configuration
#ComponentScan({"com.foo.bar", "org.foo.bar"})
http://docs.spring.io/spring-security/site/docs/3.2.0.RC2/reference/htmlsingle/#jc
You can use Java or XML based. But there is a thing
Usage of xml based configuration is decreasing in newer versions of Spring.
Like #EnableAutoConfiguration tag...
With this, web applications doesnt need any XML conf even web.xml
I started learning spring today and i have a question regarding what happens to the annotations when java files with annotations is compiled ?.
The reason i am asking this is because of the fundamental difference i see when we choose to use the xml approach vs the annotations approach , and what i think is the philosophy of spring. The way i understand is spring says that all your java classes can be simple pojo's and all the spring related config should be kept independent (Like xml file.)
In case of developing spring application using xml *.java files have no idea about spring container and are compiled in to .class without any spring related dependencies.
But now when we annotate the .java file and the file is compiled the compiled file now has all spring related dependencies hard baked in to it and no longer are your classes simple pojo's.
Is this correct ? I am not sure if i am missing some thing here.
Annotations can be considered as metadata of a class or its element (method, field, local variable...). When you put annotation, you don't implement any behaviour. You just give additional info on an element.
That way, Spring, which is in charge of instanciating its bean can collect the info with reflection (see also this site) and process it.
To conclude, your Spring beans still remain POJO and there is no difference with the XML way (...from that point of view) since Spring gets from annotations the information it would have got from XML .
I think you are right and your question is justifiable, that's the way how I think about it too.
Not only compiled code but also dependency on spring jars bother me. Once you use this annotations your resulting jar depends on spring library.
It's reasonable to store beans in model according to DDD but spring is some kind of infrastructure layer so I didn't like the dependency.
Even if you would use XML, it's useful for few placed to use attributes. E.g. #Required attribute which is useful to verify that linked bean was injected. So, I've decide to use constructor dependency injection to omit this attribute, see my article. I completely leave out the dependency on spring in the code.
You can probably find such mind hook for many annotation you want/force to use.
You can use annotations only for your configuration classes, without marking them actual bean classes. In such scenario if you not use spring you just not load configuration classes.