I have just started learning spring boot . In its official page I found out this term and I did not understand that what actually it meant in Spring boot context.
Spring Boot just decides on a set of default configured beans which you can override if you want.
For example if you include the spring boot starter pom for jpa, you'll get autoconfigured for you an in memory database, a hibernate entity manager, and a simple datasource. This is an example of an opinionated (Spring's opinion that it's a good starting point) default configuration that you can override.
See https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#using-boot-replacing-auto-configuration
Spring Boot, is Spring on steroids if you will. It's a great way to get started very quickly with almost the entire Spring stack. I'll try to summarize as what "Opinionated Defaults Configuration" would mean in practice from a programmer's perspective below:
Helps you to setup a fully working application(web app or otherwise) very quickly by providing you intelligent default configurations that you are most likely to be satisfied to start with.
It does so by something called "AutoConfiguration", where capabilities from the Spring ecosystem of products are "auto-magically" enabled in your application by adding certain dependencies to your classpath; adding such dependencies via maven or gradle is super easy.
Most auto-configuration respects your own configuration, and backs off silently if you have provided your own configuration via your own beans.
You would benefit most if you take the java config approach of configuring your Spring application.
Super silky integration of new capabilities in your application by developing your own auto-configuration components (via annotations!).
Tons of auto-configaration components available ranging from Databases(h2, derby etc.), servlet containers(tomact, jetty etc.) to email and websockets are available. It is easy to develop your own. The important thing is that others can use those technology enablements in their own components. Please feel free to contribute.
Helps write very clean code with all the heavy lifting taken care of you, so that you can focus more on your business logic.
Hope you have fun with Spring Boot; its absolutely among the very best of frameworks to have hit the market in the last decade or so.
It follows opinionated default configuration so it reduces the developer efforts. Spring boot always uses sensible opinions, mostly based on the class path contents. So it overrides the default configuration.
Related
My team currently has an old JSF 1.1 / Spring2 / Weblogic Monolith Application. As we start towards modernizing our application they want us to take our current architecture, as is, and basically shoe horn it into Spring Boot.
We aren't talking about breaking it down into micro-services at this point, but basically a lift from our current setup, taking Weblogic out of the picture, and running it in Spring Boot with Hikari Data Sources.
Can this be easily done? I haven't found a way to do it without extensive code changes and I don't mind suggesting a "Lets break it down into a micro-services in the next Product Increment" approach.
Outside of re-architecting our application (as we plan in the future) or doing quite a lot of code change, are there any other options?
If you do not use JavaEE for Weblogic, you can migrate your application to the Spring Boot easy enough. The main thing is the correct import of configuration, components, resources and properties. See: example.
If you used in your legacy project JPA or even JDBC to rewrite backend to Spring Data is not very difficult.
From my point of view the main difficulty is the JSF version you are using. I would refuse it, because: 1) it is not fully compatible with Spring boot and 2) it is already out of date today. It takes a lot of effort to put it into the Spring Boot and still it will not work completely. If there is no time and resources to change this view technology to another, you will have to finish it to Spring Boot.
I don't see other real alternatives
I've been learning spring boot for a while and as per my understanding, we use spring boot only to create the project along with dependencies and embedded servers. It doesn't have much of a role while working on the project or after the project is created.
I mean, if i were to work on an enterprise application for a company, chances are that, there is already a project created using springboot and I don't have to really use spring boot anywhere while working on that project.
Is my understanding correct?
I've tired googling, but did not find a clear answer.
No. You may still need to use the following spring-boot features after creating a project :
Externalise the application properties
Test the application using testing utilities and annotations provided by spring-boot
Use its auto-configuration feature to quickly configure if you need to enhance your application with other library/framework afterwards.
Use its developer tool to make you have a better Dev experience (e.g automatic restart the app when code changes , hot-reload static content etc.)
Use Actuator to monitor your application health and gather metrics.
I mean, if i were to work on an enterprise application for a company, chances are that, there is already a project created using springboot and I don't have to really use spring boot anywhere while working on that project.
I think you can say pretty much the same about any framework out there. I can't agree with this statement in general.
Every framework (including spring boot) provides a set of features that you may opt to use or not to use in your project.
So yes, for each existing microservice you'll have a #SpringBootApplication class.
Also probably set of configurations / practices how to work with configurations.
You'll already have also spring beans on existing project.
However software constantly evolves (otherwise it doesn't make sense to hire programmers, you know).
So when you (as a new employee) need to create a new micro service then, congratulations, you're using Spring boot features.
Other day-to-day tasks include (just a couple of example out of the head):
Create Integration Tests (#SpringBootTest)
Define new configuration Properties
Use Actuator
Use Metrics + define new metrics
Reconfigure Logging
Writing Liquidbase/Flyway migrations
Integrate new set of beans (Configurations)
Use Autoconfigurations
and so on and so forth.
If you want to really understand what you're doing while implementing these tasks you should know how do relevant features provided by spring boot work.
I have a set of projects in Spring framework and I have to Find the ones which can be converted to Spring boot.
Is there anything that is related to Spring framework and cannot be converted to spring boot ? In my research, I Could not Find something like that.
But does anyone know something, like a dependency, which would force the project to stay in Spring framework ?
Spring Boot uses the Spring Framework as a foundation and improvises on it. It simplifies Spring dependencies and runs applications straight from a command line. Spring Boot provides several features to help manage enterprise applications easily. Spring Boot is not a replacement for the Spring, but it’s a tool for working faster and easier on Spring applications. It simplifies much of the architecture by adding a layer that helps automate configuration and deployment while making it easier to add new features.
Most of the changes for migrating Spring Framework application to Spring Boot are related to configurations.This migration will have minimal impact on the application code or other custom components.Spring Boot brings a number of advantages to the development.
It simplifies Spring dependencies by taking the opinionated view.
Spring Boot provides a preconfigured set of technologies/framework to reduces error-prone configuration so we as a developer focused on building our business logic and not thinking of project setup.
You really don’t need those big XML configurations for your project.
Embed Tomcat, Jetty or Undertow directly.
Provide opinionated Maven POM to simplify your configurations.
Application metrics and health check using actuator module.
Externalization of the configuration files.
Good to refer this for migrating from Spring to Spring Boot application: https://www.javadevjournal.com/spring-boot/migrating-from-spring-to-spring-boot/
There are many people who advised me to use Spring Boot instead of Spring to develop REST web services.
I want to know what exactly the difference between the two is?
In short
Spring Boot reduces the need to write a lot of configuration and boilerplate code.
It has an opinionated view on Spring Platform and third-party libraries so you can get started with minimum effort.
Easy to create standalone applications with embedded Tomcat/Jetty/Undertow.
Provides metrics, health checks, and externalized configuration.
You can read more here http://projects.spring.io/spring-boot/
Unfortunately and I mean this out of personal frustration with Spring boot, I have yet to see any real quantified list, where the differences are explicitly outlined.
There is only qualifications such as the rubbish sentence "...opinionated view..." which are bandied about.
What is clear, is that SpringBoot has wrapped up groups of Spring annotations into its own set of annotations, implicitly.
Further obfuscating, and making the need for anyone starting out in SpringBoot to have to commit to memory what a particular SpringBoot annotation represents.
My reply therefore is of no quantifiable benefit to the original question, which is analogous to that of the SpringBoot authors.
Those behind Spring IMO deliberately set-out to obfuscate, which reflects the obtuseness of their JavaDoc and API's (see SpringBatch API's as an example, if you think I am flaming) that makes one wonder the value of their open-source ethos.
My quest for figuring out SpringBoot continues.
Update. 22-08-2022
Read this (https://docs.spring.io/spring-boot/docs/current/reference/html/using.html#using.auto-configuration) and you will figure out for yourself what "opinionated" means.
There are over 140 Config classes that Springboot can use for this opinionated view, depending on what is on your classpath.
yes, on your classpath.
Finally and bizzarely, the annotation #SpringBootApplication is a configuration annotation as it includes it.
Go figure :=)
Basically, Spring Boot is an opinionated instance of a Spring application.
Spring Boot is a rapid application development platform. It uses various components of Spring, but has additional niceties like the ability to package your application as a runnable jar, which includes an embedded tomcat (or jetty) server. Additionally, Spring Boot contains a LOT of auto-configuration for you (the opinionated part), where it will pick and choose what to create based on what classes/beans are available or missing.
I would echo their sentiment that if you are going to use Spring I can't think of any reasons to do it without Spring Boot.
Spring Boot is opinionated view of Spring Framework projects.Let's analyse it through one program taken from Spring Boot Documentation.
#RestController
#EnableAutoConfiguration
public class Example {
#RequestMapping("/")
String home() {
return "Hello World!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(Example.class, args);
}
}
It's a very basic REST API and you need to add Spring-boot-starter-web in your POM.xml for the same. Since you have added starter-web dependency, the annotation
#EnableAutoConfiguration guesses that you want to develop a web application and sets up Spring accordingly.
Spring Boot auto-configuration attempts to automatically configure your Spring application based on the jar dependencies that you have added. For example, if HSQLDB is on your classpath, and you have not manually configured any database connection beans, then Spring Boot auto-configures an in-memory database.
It's opinionated like maven. Maven creates a project structure for you which it thinks is the general pattern of projects like it adds src/main/java folder or resource folder for you.
Spring boot helps in faster development. It has many starter projects that helps you get going quite faster. It also includes many non functional features like: embedded servers, security, metrics, health checks etc. In short, it makes, spring based application development easier with minimally invading code(Less configuration files, less no of annotations).
Reference: https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/#boot-documentation-about
For developing common Spring applications or starting to learn Spring, I think using Spring Boot would be recommended. It considerably eases the job, is production ready and is rapidly being widely adopted.
Spring Boot is supposedly opinionated, i.e. it heavily advocates a certain style of rapid development, but it is designed well enough to accommodate exceptions to the rule, if you will. In short, it is a convention over configuration methodology that is willing to understand your need to break convention when warranted
For Spring Framework, you need to configure your project using XML configuration or Java configuration.
But for Spring Boot, these are preconfigured according to Spring team's view for rapid development. That is why Spring Boot is said to be an "opinionated view" of Spring Framework. It follows Convention over Configuration design paradigm.
Note: These configurations include view resolvers for MVC, transaction managers, way of locating container managed beans (Spring beans) and many more. And of course you can override any of these preconfigurations according to your need.
Spring Boot supports embedded servlet containers like Tomcat, Jetty or Undertow to create standalone applications, which Spring Framework doesn't.
Spring eliminate boilerplate code.
Spring-boot eliminates boilerplate configurations.
more
Ive been working now with the Spring Framework 3.0.5 and Spring Security 3.0.5 for several time. I know that Spring Framework uses DI and AOP. I also know that Spring Security uses DI, for example when writing custom handlers or filters. Im not sure whether Spring Security also uses AOP - so my first question is: does it?
Well, Id also like to know how Spring Security can be used for non-spring-based applications. Its written in their documentation that this is possible. Well, I wonder how - it seems like it uses DI, so how should it work in a simple java web application? I guess at least a web container which supports dependency injection is needed, correct? (Which one could that be?)
Thank you for answering :-)
[EDIT]
documentation says:
"documentation says: "Spring Security provides comprehensive security services for J2EE-based enterprise software applications. There is a particular emphasis on supporting projects built using The Spring Framework, which is the leading J2EE solution for enterprise software development. If you're not using Spring for developing enterprise applications, we warmly encourage you to take a closer look at it. Some familiarity with Spring - and in particular dependency injection principles - will help you get up to speed with Spring Security more easily.""
j2ee-based enterprise software applications......... emphasis on supporting projects using spring framework...... well this means it should be possible to work with it without Spring Framework itself!
?
AND:
Even though we use Spring to configure Spring Seurity, your application doesn't have to be Spring-based. Many people use Spring Security with web frameworks such as Struts, for example.
This is from the spring security homepage. well....
Does it use AOP ?
Yes spring-security uses AOP for its method security (you'd have to search the page to find it).
Can you use spring-security without spring ?
Generally no.
As you need to define spring beans for several spring-security elements.
But! You can use Acegi security without spring as far as I know. Which should give you close to the same functionality.
Can you secure a non-J2EE application
Definitely.
Anything that can run in a servlet container can be secured with spring-security. You just need Spring's IoC/DI.
This answer can help you on the minimal spring-security dependencies.