How to develop RestApi Using SpringBoot

Introduction

This repository contains the code samples for RESTFul Webservice developed using Spring Boot 2.0. This tutorial would be helpful for beginners who wanna start with implementing REST Api using Spring Boot.

Prerequisites

You need to install below software(s) before you begin with. If you have them already installed in your Machine, well and good.

• IDE - Any one from below of your choice:
  • Eclipse
  • Spring Tool Suite
  • IntelliJ IDEA
• JDK / JRE - Preferably Java 8
• HTTP Client to test REST Api (Any one from below of your choice):
  • Post Man - It also comes as Chrome extension.
  • Advanced REST Client - It also comes as Chrome extension.
• Apach Maven - Install only when you build project outside of your IDE. IDE does come with built in Maven.
• Apache Tomcat Server - You need this server only for Example 1

Code Samples

Example 1

Jersey - REST Example

To quickly get you the glimpse of RESTFul webservice, I chose Jersey framework to understand the REST controller configuration, HTTP Methods, Path and other stuffs. You will find the example handles the GET and POST request. Make sure you test it with HTTP Client.

JSON Model

{ "id": 123, "username": "Udhay.G" }

End points

GET: http://localhost:7878/JerseyRestApiExample/rest/welcome/user

GET: http://localhost:7878/JerseyRestApiExample/rest/welcome/user/Udhay

POST: http://localhost:7878/JerseyRestApiExample/rest/welcome/user/save

Example 2

REST using Spring Boot - Hello World

You are gonna dive into Spring Boot World in this example. A quick simple 'Hello World' service (It Greets User) that shows the dependencies and other configuration to make REST application running in Spring Boot environment. Greet yourself by making GET request with your name as Request Param, for your reference endpoints are below.

End points

GET: http://localhost:8080/user/greeting

GET: http://localhost:8080/user/greeting?name=Udhay

Example 3

Spring Boot - REST - User Service 1.0

Enough introduction. Let's get into actual work.

You will learn:

• A simple User service is created in the example to demonstrate the CRUD operation using GET, POST, PUT and DELETE HTTP verbs.
• You play with static User object to retrieve and store User info.
• You also learn about setting HTTP Response Codes (404, 500 ..) in response header based on the result of CRUD operation.

XML/JSON Model

https://gist.github.com/smartudhaya/56df064536282c5150773535ad871c28

End points

GET: http://localhost:8080/user

POST: http://localhost:8080/user/save

PUT: http://localhost:8080/update

DELETE: http://localhost:8080/user/delete

Example 4

Spring REST JPA - User Service 2.0

You will learn:

• Spring JPA - Java Persistent Api to play with Database. In memory H2 database (H2 Console: http://localhost:8080/h2-console/) is used to store and retrieve User information.
• Custom Response Handler - Handles Error/Exception in the Service in most standard way and produces erro response accordingly,
• Swagger 2.0 - Api documentation is discussed well in this example using Swagger api.

XML/JSON Model

https://gist.github.com/smartudhaya/4ec1c20694050314c2d586b74f77a980

End points

Check Swagger UI for all Endpoints - http://localhost:8080/swagger-ui.html (Make sure you imported the application and it is up & running before you access Endpoint).

Example 5

Hateoas (Hypermedia) Rest Example

You will learn:

• Hateoas implementation using Spring Boot.

XML/JSON Model

https://gist.github.com/smartudhaya/7e04ab926e35581e74d8b6fbe660fe9f

End points

GET: http://localhost:8080/product/

POST: http://localhost:8080/product/

Example 6

Internationalization (i18n)

You will learn:

• Internationalizing REST Api response using Spring Boot.
• A simple greeting Service is created that respond with 'Good Morning' message based on the Accept-language set in request header.
• For now it handles: English, French, Tamil and Hindi locale.

End points

http://localhost:9001/i18n/ (Make sure the application is running before your try to access the Endpoint)

Request Header

Accept-Language: ta (or) Accept-Language: fr (or) Accept-Language: hi

Demo Project

Employee Rest Api

To conclude the REST learning with final demo project: A simple REST Api is created for maintaining Employee inforamtion in the System.

You will learn:

• CRUD implementation using HTTP verbs
• Swagger 2.O usage
• Custom response handler implementation - To handle error and exception
• JSON and XML Negotiation

Currently am developing an Angular app that talk to this Api to create, read, update and delete Employee information. Soon will post the repository link here.

Also planning to deploy both Angular and Rest service in AWS so that you can see live demo of it.

Watch the space !

XML/JSON Model

https://gist.github.com/smartudhaya/842879f043019e74130b1da33b016845

End points

Check Swagger UI for all Endpoints - http://localhost:8080/swagger-ui.html (Make sure you imported the application and it is up & running before you access Endpoint).

Deployment

For Example 1: Run / Deploy on Apache Tomcat Server.

For other examples, embedded tomcat server that comes with Spring boot will be used.

If you wish to deploy the service in AWS, please follow this link - Deploying a Spring Boot Application on AWS Using AWS Elastic Beanstalk.

Contributing

Please read CONTRIBUTING.md for details on our code of conduct, and the process for submitting pull requests to us.

Authors

• Udhayakumar Govindarajan

License

This project is licensed under the Apache License - see the LICENSE.md file for details