Use groovy & grails in your spring boot projects

Editor's Notes

• #3: My name is Fatima Casau I’m a software engineer since seven years ago and currently, I work as a Java Architect and Scrum Master in Paradigma Tecnologico Since 6 years ago, I’m specialized in Groovy & Grails technologies and recently, I'm working with Spring Boot. For this, I'm here and I want to tell you my experience about this
• #4: Well... In short, What are we going to see in this talk? I’m going to talk about Spring Boot and Groovy and where you could use Groovy in your spring boot projects We go to see... What is Spring Boot What is Groovy And, how or where use both. For example Using Gradle Developing tests with groovy and the Spock framework Using Groovy Templates Or why not?, Anywhere in your projects Also, We will see how to use GORM and GSP’s in a Spring Boot project, outside Grails
• #5: In First Place, What is Spring Boot? Question: How many people know Spring Boot? Question: How many people are using Spring Boot currently? (If many people -> As many of you know...
• #6: … Spring Boot is a new project from Spring that allows you to develop standalone Spring MVC applications easily. Probably, You think about the many configurations there are in Spring projects, but, Spring Boot, follows Convention Over Configuration allowing Autoconfiguration and configuration with annotations, eliminating the necessity of use XML configuration files. In other hand, Spring Boot allows you to start and build production applications quickly, because provides an embedded container and database according to the dependencies specified in the build system, so, you don't need to configure this to start to work. Additionally, we can use Groovy, and, of course, all of its features, only including a dependency. Finally, we can run an application quickly thanks to Spring Boot CLI Tool Of course, you can find examples and documentation about all of this on the Spring Boot website in projects (dot) spring (dot) io (slash) spring-boot
• #7: We go to see a little but powerful example: We can develop an application that can be contained in a single tweet and execute it quickly with Spring Boot CLI
• #8: First, I want to talk about the GVM Tool GVM is a Tool for managing versions of multiple Software Development Kits To use it, you can download in its website gvmtool.net Once you have downloaded, you can see witch framework are available only typing 'gvm' you can download Spring Boot with the GVM Tool Once you have installed GVM tool, only you need to do is execute in a terminal gvm install springboot and this will install the latest version of spring boot
• #9: Here we have the example: a groovy script with: an annotation (at) Controller that means this is a Controller component two more annotations, to determine the URI and response of the controller and finally, a method that returns the message “Hello World” To execute this, we open a terminal and go to the path that contains the groovy script and type spring run helloWorld.groovy (By command line) go to workspaces/greach14 spring run helloWorld.groovy Later, go to Chrome and type localhost:8080 and see the result It's only you need to do to start an example
• #10: In second place, The next lead actor in this talk, of course, is Groovy! Question: How many people know Groovy? Question: How many people are using Groovy currently?
• #11: What is Groovy? Groovy is a dynamic language, optionally typed with static-typing and static compilation capabilities for the Java platform Thanks to an easy and expressive syntax it’s easy to learn for java developers. Furthermore, it integrates easily with any Java program, delivering powerful features, including closures, runtime and compile-time meta-programming, functional programming, scripting, powerful tests...and so on So..., if we combine the power of Spring Boot with the features of Groovy we obtain a couple of powerful tools that allows to developers work in an easy and more productive, interesting and amazing way
• #12: Then.... Where could you introduce Groovy in your spring boot applications? In short, anywhere!, but we go to see the different sites in the project where you could use Groovy bit by bit
• #13: The first option is use Groovy in the process to build the project using Gradle
• #14: With Spring Boot we can build our projects with Maven, but also, we can use Gradle With Maven, we have to manage a static xml file, the pom.xml file, but with Gradle we have a flexible and modular groovy file that it's more easy to read thanks to a friendly syntax based on Groovy DSL’s and a plugin model With Gradle, we have a powerful building tool with many features such as support for multi-project, dependency management based on Apache Ivy, with support and integration with Maven and Ivy repositories.. And also, we have a large list of tasks based on Ant to manage our application
• #15: See you how to use
• #16: Like with Spring Boot, we can download and manage our versions of Gradle with GVM Tool Later, we only need to create a build.gradle file with some dependencies and execute the command gradle build to compile, test and assemble the code into a jar file. If we execute gradle ‘tasks’ we can see a list of available for our project.
• #17: This is an example of build.gradle file. We can see some plugins such as groovy, idea or spring boot, of course. Also, we have got the configurations about the jar file, the name and the version of our project Below, the repositories configuration and the dependencies. If you include some plugin more and execute the ‘tasks’ command again, you will can see new tasks in the list, the tasks are related with the dependencies available in the project
• #18: Other site where use Groovy is implementing tests using the framework Spock. This is my favorite section I like to implement tests with groovy and Spock framework
• #19: Why? Spock is not only a test framework, Spock is a test specification for Groovy and Java projects With an expressive language, its also based on Groovy DSL’s and this makes our tests become easy to read and well documented. Moreover, when an assertion failed, the exit is very intuitive and easy to read as well.
• #20: Let me to show some examples of simple spock tests and how to use its test blocks
• #21: For example, With Spock we can define test with descriptive signatures. We can organize the code in intuitive blocks such as: “given” or “setup” to setup initial variables, for example, “when” to execute an action and “then” to test the result. In this block we needn’t asserts, only test if a sentence is true or not by the use of groovy truth
• #22: In the other hand we have got two blocks more, ‘expect’ and ‘where’. With this blocks we can test different combinations of data in only one test and later, we will see what iterations it has failed and what not easily
• #23: Here, we can view the way to show the assertions failed. It’s very easy read the failure In addition to these, we have more features with diferents tags and utilities. Please visit the documentation and test the examples I think that this is a good point to start with Groovy and know the features and the simplicity of the language
• #24: Another possibility is the use of Groovy templates
• #25: Groovy Template Framework is based on MarkupBuild that permits a pretty and easy way to write readable Groovy Views using Groovy DSL's Also, provide an easy way to replace variables in the view
• #26: See you an example
• #27: In this block, we have an ‘ul’ block where a people list is iterated and for each person, its name is printed in a li element. We can pass a list and iterate it in the view easily If we return this view and, in the model, we send this list of people, we obtain the result printed in the line below Right?
• #28: Well..., Really, You can use Groovy anywhere in your spring boot project
• #29: Yes! Anywhere! We can use Groovy in controllers, services, domain classes… If we need, we can combine Java & Groovy easily, that is, if we need have classes in Java & in other hand, classes in Groovy, it is possible. And, you must to know that the most important features of use groovy over java is that our applications will be very simple, expressive and flexible, will have less code and, if there are less code, there will be less errors. This is a fact! Furthermore, with Groovy we have many features available than with Java, because Groovy provides the GDK as an extension of JDK with many more features about the use of Strings, collections, control structures, closures… and so on. Finally, you could think about compilation in runtime or dynamic typing, but, if you are worry about this, you must to know that you can use Static Compilation or Static Typing with the annotations (at)CompileStatic and (at)TypeChecked in your classes.
• #30: Here, I won't to show anything different, only, the same controller in the beginning of the talk but with the use of CompileStatic annotation
• #31: Only, you need to add the annotation (at)CompileStatic in the definition of the class This code should already run as fast as Java.
• #32: The use of GORM with Spring Boot GORM is the Grails Object Relational Mapping
• #33: Since Grails 2.4, It is possible to use GORM outside of Grails, and this permits access relational database or MongoDB with GORM in a Spring Application including the correct dependency in the project. With GORM we can map the entities automatically, we have dynamic finders, criterias, persistence methods, validations… and more. We don’t need implements getters & setters methods, constructors or specify the primary key. With this features, our code is even simple
• #34: See some code...
• #35: This is a domain class implemented with Groovy and using GORM. The annotation @Entity indicates that we are using GORM. We can specify some constraints easily, or some mapping options.
• #36: Now, see how to use a domain class with GORM. For example. We can instance new object of the class with a map in the constructor and we have not defined this constructor In other hand, We have dynamic finders without implement it, findAll, get, findBy… any attributes… and many more
• #37: As GORM, we can use GSP’s (Groovy Server Pages) outside of Grails.
• #38: With GSP’s we have a large list of Tag libraries that we can use to make our views more simple. Also, we can create easily our own tags or we can define layouts, templates and reuse the code easily
• #39: See some examples of predefined tags:
• #40: conditional tags as g:if and g:else iterator tags as g:each or using a finder that iterates a list with a condition g:dateFormat to format dates in view easily g:render to render templates sending a model and many more! Also, remind that you can implements your own tags easily
• #41: well… after all of this… What are the conclusions? (Almost my conclusions)
• #42: If you use Groovy… as I’ve said before, your application has less lines of code, so, less errors, if there are errors, you can find them easily so, you will be more productive Remind that with Groovy you can get more features for your project, you can implement cool test and you can use cool utilities, this is: you have a super-vitaminized Project! Then, Why not use Groovy in your Spring Boot project? Please, use Groovy! Try to introduce bit to bit in the application. Begin with Spock tests, later, introduce groovy in the code of your services, and so on.
• #43: But, one moment...
• #44: We have talked about MVC Spring Based Apps Convention Over Configuration Application Bootstrapping Groovy Language GORM GSP’s…. This sounds like Grails! And also, Grails 3.0 is built on Spring Boot!! So, I want to leave you with a question,... Why not use Grails instead of Spring Boot?
• #45: The next lead actor in this talk is Groovy! Question: How many people know Groovy? Question: How many people are using Groovy currently?
• #47: One more thing. In Paradigma, we are hiring for people specialized in many technologies as you can see, so, if your are interested or you know somebody could be interested, please, send us your CV <number>