Which dependency should be used to integrate Apache Camel with Spring Boot - spring-boot

Apache Camel provides two ways to integrate with Spring Boot:
camel-spring-boot
camel-spring-boot-starter
When I look at the starter then I see that it only includes camel-spring-boot and spring-boot-starter. What is the difference then and what are the advantages of using starter?

At the moment of writing this answer, camel-spring-boot is only supported from Camel 2.15 and camel-spring-boot-starter only from Camel 2.17, which is important considering the current version that your project is using.
Then the major difference between these two dependencies, lies in the "opinionated" auto-configuration provided by the starter.
camel-spring-boot, should be used if you want just to include a jar to make your camel routes auto-discovered by spring boot, this also gives you the freedom to update this dependency regardless of your spring-boot version.
camel-spring-boot-starter, (recommended way to go) should be used if you want a collection of dependencies (including camel-spring-boot) that provides the best developer/user experience, due to the fact of customizable properties, additional libraries, and default configuration for the camel library. Check the reference documentation for the starter: https://camel.apache.org/components/latest/spring-boot.html#_spring_boot_auto_configuration
Summary
Use camel-spring-boot, if you want a vanilla jar to use camel with spring boot
Use camel-spring-boot-starter, if you want an automatic-configured component to start to develop with.

You should always use the camel-xxx-starter dependencies, as these are the Camel components that is support with Spring Boot. Also as mentioned they provide auto configuration and some of them additional capabilities.
If there is no camel-xxx-starter component then its because its not supported on Spring Boot with Camel.
See more at: https://github.com/apache/camel/tree/master/platforms/spring-boot/components-starter#camel-component-starters

Related

Is it possible to write lib for projects using different versions of Spring?

I'm writing a lib for projects using different versions of Spring. The lib itself is based on Spring too ( more precisely, Spring Cloud Sleuth). For now, I use different versions for different projects( version1 for projects using Spring boot 2.0.x, version2 for projects using Spring boot 2.3.x, etc). Apparently, the maintenance took a lot of time and made some confusion. Is there a runtime mechanism like #Conditional but for dependencies?
First, check the Spring Cloud compatibility matrix. As you can see, different Spring Cloud versions support different Boot versions.
I would do the same for your library and maintain different versions of it.
Your can have optional dependencies on Sleuth and set things up using #Conditional annotations (e.g.: #ConditionalOnClass) but I would not recommend that.
Sleuth 2.2.x (Hoxton) uses Brave's API (btw 2.x is not supported anymore, you should upgrade). Sleuth 3.0.x (2020.0.x aka Ilford) and 3.1.x (2021.0.x aka Jubilee) have their own API and they abstract the tracer libraries away. You can use these interfaces/classes to detect the version and configure them differently but when you compile your library you can have classpath issues because you have 2.2.x, 3.0.x, and 3.1.x on your classpath.
Another thing you can do is modularize your library and put all of those things that does not depend on Spring into a "core" module then create smaller adapter/autoconfiguration/starter modules for every version of Spring Cloud you want to support.

Convert project from Spring framework to Spring boot

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/

Why are there no Java classes in Spring Boot starters JARs?

On springboot 2.0 I want to know why spring authorities do this?
spring-boot-starter-jdbc-2.0.0.jar why not content????
This is done on purpose.
The code for the auto-configuration is contained in the spring-boot module; Spring Boot starters are "just" POMs bringing all the dependencies that will trigger the auto-configuration for that use case.
Third party starters (i.e. maintained by the community) can ship auto-configuration code as well.
You can learn more about how to create your own starter and why they're structured like this in the reference documentation.

Spring Boot 2.x Metrics classes

I have started using spring boot 2.0.0-Snapshot and I see that all Metric related classes and interfaces does not exists ?
Example:
The jar spring-boot-actuator-2.0.0.BUILD-SNAPSHOT.jar does not have package
org.springframework.boot.actuate.metrics.writer at all
Are they moved to somewhere else?
In Spring Boot 2 the previous metrics implementation has been replaced by integration with Micrometer. From the release notes:
Spring Boot’s own metrics have been replaced with support, including auto-configuration, for Micrometer and dimensional metrics. You can learn more about Micrometer in its user manual and Spring Boot’s reference guide
I can't find any guide for migrating from 1.x Spring Boot Metrics to 2.x Spring Boot Metrics but this change is quite recent so I suspect any such docs are a TODO. In the meantime, you could perhaps dig into the Pull Request or follow the Spring Boot 2 docs ...
Micrometer provides a separate module for each supported monitoring system. Depending on one (or more) of these modules is sufficient to get started with Micrometer in your Spring Boot application. To learn more about Micrometer’s capabilities, please refer to its reference documentation.

adding spring-data-rest ontop of spring-data-jpa

i created a maven project, and added all dependencies i need.
i have some repositories using the spring-data-jpa, and i added some integration tests.
now i need to add ontop of it spring-data-rest, if i understand it is based on springmvc.
but all examples i found, i need to add spring boot to start the app.
i noticed also all new spring projects use spring boot.
this means that i have to learn and use it for my projects?
how can i use spring-data-jpa+spring-data-jpa with an existing servlet3 project
The reason all examples are written using Boot is that Boot is indeed the way you should start a new Spring project these days. It free's from a lot of the tedious work of setting up the infrastructure, finding dependencies in the right version etc.
To use Spring Data REST without Boot, simply add the necessary dependencies to your project. The easiest way to do this is to use the Spring Data Release Train BOM (which will help you pulling in the correct matching versions) along side the version-less dependency declarations for Spring Data REST WebMVC and - in your case - Spring Data JPA.
Then go ahead and either register RepositoryRestMvcConvfiguration as Spring bean (either through XML configuration or JavaConfig).
All of this is also documented in the reference documentation.

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