REST tutorial introduction

Greetings!

In this tutorial series, we are going to study RESTful services with Spring.

We are going to build a TodoApp in this series since it is one of the easiest way to touch the technical stack.

You can find the complete source code here Todoapp

For the simplicity i'm going split tutorial into smaller parts.

1. Section 1: CRUD
   • Introduction
   • Repository layer
   • Service layer
   • Controller layer
2. Section 2: Error handling
   • Exception handling
   • Validations
3. Section 3: Security
   • Add token authentication
   • Enhance token with JWT
4. Section 4: User interface
5. Section 5 : Miscellaneous
   • Logging with logback

Goal

• Create a RESTful service using Java tech stack.

What you need

• Java 8
• Gradle 4
• IDE

REST

REST stands for REpresentational State Transfer. It is an architectural style rather than a strict protocol. Not a standard but a set of constraints, such as being stateless, having a client/server relationship, and a uniform interface.

rest wiki

Spring Framework

The Spring Framework is an application framework and inversion of control container for the Java platform.

spring doc

Spring Boot

Spring boot is a Spring based production-ready project initializer which create Spring-powered, production-grade applications and services with absolute minimum fuss.

spring boot doc

HTTP methods

HTTP Verb	CRUD
GET	Read
POST	Create
PUT	Update
DELETE	Delete

HTTP Status Codes

HTTP code	Status
200	OK
201	Created
204	Deleted (No content)
400	Bad Request
401	Unauthorized
403	Forbidden
404	Not found
405	Method not allowed

Define our REST API

First of all let's define our API.

• return all Todo entries: '/todos' : GET request 
• create a new Todo entry : '/todos' : POST request 
• delete a Todo : '/todos/{id}' : DELETE request 
• update a Todo : '/todos/{id} : PUT request 
• view a Todo: '/todos/{id}' : GET request

Create the starter project

• Go to http://start.spring.io/
• Enter Group and Artifact 
• Select Web, H2, JPA and Lombok dependencies 
• Click Generate Project to generate and download the project

Modify the starter

• Create HelloController and add following,

• Go to project location and run the project

         gradle bootrun

• Go to web browser and enter http://localhost:8080/

Congratulations!!! you just created your first service ;)