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Thursday, March 23, 2023

7 Reasons to use Spring Framework for Creating RESTful Webservices in Java

REST has now become a standard way to develop web services and when it comes to Java, there are many frameworks and libraries available like JAX-RS, Restlet, Jersey, RESTEasy, Apache CFX, etc, but I encourage Java developers to use Spring framework to develop RESTful web services. But, some of you might ask, why use Spring Framework to develop RESTful web services in Java? What is the advantage and why it's better than other frameworks and libraries available out there? Well, the most important reason I think to use Spring for developing RESTful web service is that you can use your Spring MVC experience to develop RESTful web services.

This is one of the biggest advantages i.e. leveraging your years of experience on Spring MVC to expose your application as REST APIs. Another reason is that Spring has excellent support for developing RESTful web services.

In the last couple of versions, starting from Spring version 3.0, it has provided a lot of enhancements to Spring MVC to provide first-class REST support. It has provided dedicated annotations e.g. @RestController and @ResponseStatus to make the development of RESTful resources even easier in Spring 4.0.

It's also not only helps you to create RESTful web services but also provides classes to consume REST resources e.g. you can use RestTemplate class to consume RESTful resources.

There are many more utility classes and annotations which make the development of RESTful web services in Spring easier and seamless and I'll share a couple of them in this article to prove my point that using Spring to develop RESTful Web service is the right decision.

By the way, if you are new to the Spring framework then I also suggest you join a comprehensive and up-to-date course to learn Spring in depth. If you need recommendations, I highly suggest you take a look at Spring Framework 5: Beginner to Guru, one of the comprehensive and hands-on courses to learn modern Spring. It' also the most up-to-date and covers Spring 5. It's also very affordable and you can buy in just $10 on Udemy sales which happen every now and then.

How Spring Supports RESTful Web Services?

As I told you in the first paragraph that we can use Spring MVC to create and consume RESTful web services. Now, let's see those supports in a little bit more detail so that you can make the best use of them and quickly develop the RESTful services you always wanted to.

1. InBuilt HTTP Method Support

In Spring MVC, a controller can handle requests for all HTTP methods, which is a backbone of RESTful web services. For example, you can handle the GET method to perform read operation, POST method to create resources, PUT method to update resources, and DELETE method to remove resources from the server.

 From Spring 3.2 onwards, you can also handle PATCH requests. Btw, if you are not familiar with the Spring MVC framework then Spring MVC For Beginners on Udemy is a good place to start.

2. Easy Data Conversion

In the case of REST, the representation of data is very important and that's why Spring MVC allows you to bypass View-based rendering altogether by using the @ResponseBody annotation and various HttpMessgeConverter implementations.

By using these two you can directly send a response to the client e.g. the resource clients want and also in the format they want.

I'll write more about @ResponseBody annotations and HttpMessageConverter in this blog in the coming articles, but if you can't wait, I suggest you go through REST with Spring Certification class by Eugen. He not only explains the basic details of developing RESTful web services but also advanced details like versioning and securing your REST APIs using Spring Security.

7 Reasons for using Spring to develop RESTful Web Services in Java

3. Specialized Controller for REST

The Spring 4.0 release added a dedicated annotation @RestController to make the development of RESTful web services even easier.

If you annotate your controller class using @RestController instead of @Controller then Spring applied message conversations to all handler methods in the controller.

This means you don't need to annotate each method with the @ResponseBody annotation. This also makes your code much cleaner. You can read more about it on my post difference between @Conroller and @RestController in Spring.

4. Easy to Extract URL Parameters

One of the main differences between REST web services and a normal web application is that REST passes resource identifier data in URI itself for /messages/101 while web application normally uses a query parameter for /messages?Id=101.

If you remember, we use @RequestParam to get the value of those query parameters but not to worry, Spring MVC also provides a @PathVariable annotation which can extract data from URL. It allows the controller to handle requests for parameterized URLs.

You can learn more about @PathVariable in my post difference between @RequestParam and @PathVaraible in Spring.

5. Easier Representation of Data

Another key aspect of RESTful web services is Representation like the same resource can be represented in different formats e.g. JSON, XML, HTML, etc. Thankfully Spring provides several view implementations and view resolvers to render data as JSON, XML, and HTML.

For example, ContentNegotiatingViewResolver can look at the file extension of requests or Accept header to find out the correct representation of a resource for the client.

6. Annotation Support for Request and Response

Similar to @ResponseBody annotation, which is used for converting the response to the format client wants (by using HttpMessageConverts), Spring MVC also provides @RequestBody annotation, which uses HTtpMethodConverter implementations to convert inbound HTTP data into Java objects passed into a controller's handler method.

You can further see REST with Spring MasterClass to learn more about @RequestBody annotation and how to effectively use it to develop RESTful web services in Java with Spring.

7. RestTemplate to Consumer APIs

Spring Framework also provides a Template class, RestTemplate, similar to JdbcTemplate, and JmsTemplate, which can consume REST resources. You can use this class to test your RESTful web service or develop REST clients.

I have already talked about this class in my earlier blog posts and you can see this tutorial for a live example of using RestTemplate to consume JSON from a RESTful web service in Java.

These were some of the important features of the Spring MVC framework which assist in developing RESTful web services. As I told the most important reason for me to choose Spring for developing RESTful resources is that I can use my existing knowledge of the framework, which means no steep learning curve. If you look at a high level, developing RESTful services is not very different from developing a web application.

The fundamental difference is that in the case of the former, we mostly deal with human users were in the case of REST, you have to deal with non-human users mostly rich JavaScript clients and mobile applications. This key difference then derives other differences e.g. representing data in JSON or XML instead of HTML which is suitable for human users but not for non-human systems.

If you are still not convinced, I suggest you go through REST with Spring Certification class on Baeldung, probably the best resource on Spring with REST at the moment, which will give you enough reason to stick with Spring for developing both RESTful resources and REST clients.

Other Spring and REST Resources you may like

Thanks for reading this article, if you like these reasons for developing RESTful web services using Spring then please share with your friends and colleagues. If you have any questions or feedback, then please drop a note.

P. S. - If you are new to Spring Framework and want to learn Spring Framework in-depth in a guided and more structured way then I highly recommend you to join Spring & Hibernate for Beginners (includes Spring Boot) course by Chad Darby on Udemy. It's a great course to learn three key skills core Spring, Hibernate, and Spring Boot in one course. 


Unknown said...

JAX-RS is a specification, not a framework or a library

rere_rezaei said...

Thanks Javin.

It was Very useful said...

can you share a coding for spring mvc with REST webservices to produce response in xml format? How to incorporate jaxb in this scenario? Please provide a end to end example with eclipse java snippet.

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