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I have created many REST web services providing JSON before using PHP and NodeJS and I know the concept.

Now I want to re-implement those web services using Java instead. After doing some research for how to implement web services in Java, I found some standards or libraries like JAX-RS, Spring or Jersey. However I not know the difference between all of them.

I wonder why we do not make a simple servlet which will be called through HTTP request and returns the result in the JSON format. And if I wanted to use one of these standards, what would be the best choice to implement web services that accepts HTTP requests and returns JSON?

cassiomolin
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Mohamed A. Shebl
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    Because if you create a simple servlet, then you'll have to do all the boilerplate code yourself that is elegantly handled by the existing frameworks. Which happens to be the answer to all of "why should I use X instead of doing Y myself" questions. – Kayaman May 11 '16 at 08:47

2 Answers2

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You can use a stone to drive a nail into the wall. For sure you can. But why would you do that if you have a hammer available? Using the proper tool will make your life a lot easier.

In a similar way, you can create REST applications using only the Servlet API. However, there are other APIs that are designed to create REST applications. So, why don't you use them?

JAX-RS and Jersey

JAX-RS, currently defined by the JSR 339, is the standard Java API for creating RESTful web services and it's built the top of the Servlet API.

It's important mention that JAX-RS is an specification. In order to use it, you will need an implementation, such as Jersey, which is the reference implementation.

A few resources that may be useful:

Spring Framework

The Spring Framework allows you to create RESTful web services and it can be easly integrated with other Spring projects.

A few resources that may be useful:

Other resources you may consider useful

cassiomolin
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You can do it using Servlet API actually. But you won't get all the benefits of JAX-RS like url mapping, parameters injection, ... You would have to write all this "by hand".

By the way, the difference between JAX-RS and Jersey is that JAX-RS is a specification, a standard and Jersey is an implementation of that standard. There are other implementations as well (RestEASY for example). Spring also has a module for REST services.

ACV
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