Best way to implement RESTful API in Java?
By: Ahmed Ahsan Khan
Tags: Web Services, Java, Spark, Programming, Web Development

Web Services Diagram

When we talk about Java as a programming language, one of the biggest critics we hear is that Java is a lengthy language to implement and to implement something we need to write lines of codes to achieve a task compared to languages like Python or React for that matter.

What if I tell you that now you can implement RESTful APIs in Java with a minimum code using Java Spark Web Framework.

In one of the projects which I was implementing previously, I had to implement a restful API for exposing data and to be consumed by the client applications such as a website or a mobile app. As my expertise was Java and so I wanted something implemented in Java. I went online to search for restful API implementation and that’s where I found Spark Web Framework.

What is Spark?

Spark Framework is a simple and expressive Java web framework DSL built for rapid development.

I had worked with few Java web frameworks before like Struts 1 and 2, Application Development Framework (ADF) by Oracle, Spring Framework by Pivotal Software and Java Servlets. Therefore I have a fair knowledge of different java web framework implementations around.

Spark is something new I had to learn. Spark is a microframework for creating web applications in Kotlin and Java 8. It is a very simple and easy to use framework that helps rapid development for web developers. The best thing about spark which I like is that you don’t have to create your own get and post methods like the ones in a servlet rather you can just use built-in functions of spark library to expose particular URLs as shown in the image below and run it with URL: http://localhost:port/hello.

Configuration for Spark in POM.xml

Sample Hello world code using Spark API Lambda expressions.

More HTTP methods sample

As seen in the examples above, this is how easy it is to implement RESTful APIs with Spark web framework. No need for separate get and post methods or unnecessary inheriting classes or implementing interfaces like in other Java web frameworks. For a complete Spark documentation head to its official web page of Spark Documentation.

The reason for mentioning spark here is that developers find it hard and time-consuming for writing long lines of code. Web services are everywhere and we need to connect them with the client applications or websites to make it usable.

For data security and privacy we can’t keep everything in one place and so there is a need for separation of code as well between server-side programming and client-side implementations. In one of my previous articles, I mentioned why every developer should understand and know the concepts of RESTful APIs and now once you have understood it then you should try to implement it and this is where Spark Web Framework plays its role.

If you are a web developer in Java, Spark can help you implement a web application in a less time-consuming manner with minimal boilerplate compared to other Java web frameworks. As Spark is a micro framework and lightweight, it provides only a small number of features compared to other frameworks but at the same time, it is so simple that you can create your web application within a small amount of time.

Happy Reading.

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