[JAVA] Introduction to Ratpack (7) --Guice & Spring

Ratpack introductory series

  1. Introduction to Ratpack (1) --What is Ratpack
  2. Introduction to Ratpack (2) --Architecture
  3. Introduction to Ratpack (3) --Hello world detailed explanation
  4. Introduction to Ratpack (4) --Routing & Static Content
  5. Introduction to Ratpack (5) --Json & Registry
  6. Introduction to Ratpack (6) --Promise
  7. Introduction to Ratpack (7) --Guice & Spring
  8. Introduction to Ratpack (8) --Session
  9. Introduction to Ratpack (9) --Thymeleaf

DI container

Ratpack as I wrote before By registering various parts in the Registry class, a modular architecture is realized. It's ideal and flexible in itself, but I think large-scale development will still require a full-fledged DI container. Ratpack can use the DI function of Google Guice or Spring as Registry.

Guice

You can create a Registry from the ratpack.guice.Guice class. Please note that the name is com.google.inject.Guice. This is an example of creating a Registry from the ʻInjector` class.

Injector injector = Guice.createInjector( new CustomModule() );
Registry registry = ratpack.guice.Guice.registry( injector );

You can also create modules only from the API inside Ratpack. The type is Function <Registry, Registry>, but you can pass it directly to RatpackServerSpec.registry ().

Function<Registry, Registry> registry = ratpack.guice.Guice.registry( bindings -> {
    bindings.module( CustomModule.class );
} );

It should be noted that the addition of modules is affected in order. The contents will be overwritten in the module added later.

Usage is the same as normal Registry. You can get the class registered in the Guice injector from the Registry API. If you specify a handler etc. by class name, it will be fetched from the container. Instances are managed by Guice, so you can specify dependencies with @ Inject just like you would with regular Guice code.

public final class CustomHandler implements Handler {

    private Database database;

    @Inject
    public CustomHandler( Database database ) {
        this.database = database;
    }

    @Override
    public void handle( Context ctx ) throws Exception {
        ctx.render( "CustomHandler: " + database.find() );
    }
}
Action<Chain> handlers = chain -> {
    chain.all( CustomHandler.class );
};

InjectionHandler

Ratpack provides the ʻInjectionHandler` class to reduce Guice's boilerplate.

public static final class CustomInjectionHandler extends InjectionHandler {
    public void handle( Context context, Database database ) {
        context.render( "CustomInjectionHandler: " + database.find() );
    }
}

The class that inherits ʻInjectionHandler implements only one function with the name handlerandContextas the first argument. AfterContext`, describe the dependency you want to inject as an argument. Internally, it takes the form of delegating processing to the method by reflection in response to the handler call. Considering performance and IDE support, I personally prefer not to use it much.

Spring

You can create a Registry from a Spring DI container with theratpack.spring.Spring.spring ()method.

Registry registry = Spring.spring( Application.class );

The class specified in the argument is the class with the @SpringBootApplication annotation. Just like you would use it in a regular Spring application, the components are searched in the classpath and those classes can be retrieved from Registry.

@Service
public class CustomRenderer implements Handler {

    private final CustomRepository repository;

    @Autowired
    public CustomRenderer( CustomRepository repository ) {
        this.repository = repository;
    }

    @Override
    public void handle( Context ctx ) throws Exception {
        ctx.render( "Hello from Spring Boot!" );
    }
}
@Repository
public static class CustomRepository {
    public String find() {
        return "This is the mock database.";
    }
}
Action<Chain> handlers = chain -> {
    chain.all( CustomRenderer.class );
};

Summary

I think the use of DI containers is almost mandatory in the Java ecosystem. Ratpack provides support for two of the most popular DI containers, Guice and Spring. Guice is also used to integrate each of Ratpack's extension modules.

Ratpack and Guice are tightly integrated, and DI itself is a powerful way to loosely couple applications. We recommend that you use it positively.

Recommended Posts

Introduction to Ratpack (7) --Guice & Spring
Introduction to Ratpack (8)-Session
Introduction to Ratpack (6) --Promise
Introduction to Ratpack (9) --Thymeleaf
Introduction to Ratpack (2)-Architecture
Introduction to Ratpack (5) --Json & Registry
Introduction to Spring Boot ① ~ DI ~
Introduction to Spring Boot ② ~ AOP ~
Introduction to Spring Boot Part 1
Introduction to Ratpack (1) --What is Ratpack?
Introduction to Ruby 2
[Introduction to Spring Boot] Form validation check
Spring Fox ① Introduction
Introduction to SWING
Introduction to Ratpack (Extra Edition) --Using Sentry
Introduction to web3j
Introduction to Micronaut 1 ~ Introduction ~
[Java] Introduction to Java
Introduction to migration
Introduction to Ratpack (3) --hello world detailed explanation
Introduction to java
Introduction to Doma
Introduction to Ratpack (Extra Edition) --Ratpack written in Kotlin
An introduction to Spring Boot + in-memory data grid
[Introduction to Spring Boot] Authentication function with Spring Security
Introduction to JAR files
Introduction to RSpec 1. Test, RSpec
Introduction to bit operation
Introduction to PlayFramework 2.7 ① Overview
Introduction to Android Layout
Introduction to design patterns (introduction)
Introduction to Practical Programming
Introduction to javadoc command
Introduction to jar command
Introduction to lambda expression
Introduction to java command
Introduction to RSpec 2. RSpec setup
Introduction to Keycloak development
Introduction to javac command
[Introduction to Spring Boot] Submit a form using thymeleaf
Introduction to Design Patterns (Builder)
Try Spring Boot from 0 to 100.
Introduction to RSpec 5. Controller specs
Introduction to Android application development
Introduction to RSpec 3. Model specs
Introduction to Metabase ~ Environment Construction ~
(Dot installation) Introduction to Java8_Impression
Introduction to Design Patterns (Composite)
Introduction to Micronaut 2 ~ Unit test ~
Introduction to JUnit (study memo)
Introduction to design patterns (Flyweight)
[Java] Introduction to lambda expressions
Introduction to Apache Beam (2) ~ ParDo ~
[Ruby] Introduction to Ruby Error statement
Introduction to EHRbase 2-REST API
Introduction to design patterns Prototype
GitHub Actions Introduction to self-made actions
[Java] Introduction to Stream API
Introduction to Design Patterns (Iterator)
XVim2 introduction memo to Xcode12.3
Introduction to RSpec-Everyday Rails Summary-