[JAVA] Introduction to Ratpack (1) --What is Ratpack?

Ratpack introductory series

What is Ratpack

Ratpack is a web application library for Java / Groovy published in Apache License v2.

Feature

Event driven

Since Ratpack uses Netty for communication, it operates event-driven like node.js. Therefore, it is possible to realize scalable and high-performance HTTP communication.

asynchronous

Non-blocking communication requires support for asynchronous programming, which Java is not good at. Ratpack supports this with the Promise class and also has extensions for RxJava.

Non-opinionated

One of the development goals of Ratpack is to be "flexible and non-opinioned when integrating with other tools and libraries".

Scalability

There are extension modules such as ratpack-groovy, ratpack-guice, ratpack-jackson, ratpack-rxjava, ratpack-session.

What Ratpack is not aiming for

According to the official page, the following are listed as ** not ** goals for Ratpack:

Fully integrated, "full stack" framework
Providing all the features you may need
Providing an architecture or framework for "business logic"

Hello World

`build.gradle`


dependencies {
    compile 'io.ratpack:ratpack-core:1.5.1'
}

`Sample.java`


public final class Sample {

    public static void main( String[] args ) throws Exception {
        RatpackServer.start( server -> server
                .handlers( chain -> chain.get( ctx -> ctx.render( "hello, world" ) ) ) );
    }

}

キャプチャ.PNG

As you can see, it is made on the premise that lambda expressions are used a lot, so if you are not familiar with lambda expressions, please learn it.

Why did you decide to write this article

I was sick of Spring and was looking for an alternative library and came across Ratpack. However, there was not much information in Japanese, and even if it was, it was Groovy instead of Java, and the official documentation was sometimes difficult to understand. Therefore, I decided to write this article series, hoping to support those who are going to use Ratpack from now on.

In the next post, I'll look at how to use Ratpack in detail.