A Step by Step guide to create CRUD Restful APIs using Spring Boot + Spring Data JPA with H2 in-memory database

Introduction

We will be implementing the below CRUD Restful APIs to manage items for a Catalogue Management System.

HTTP Method	API Name	Path	Response Status Code
POST	Create Catalogue Item	/	201 (Created)
GET	Get Catalogue Items	/	200 (Ok)
GET	Get Catalogue Item	/{sku}	200 (Ok)
PUT	Update Catalogue Item	/{sku}	200 (Ok)
DELETE	Delete Catalogue Item	/{sku}	204 (No Content)
POST	Upload Catalog Item Picture	/{sku}/image	201 (Created)

Technology stack for implementing the Restful APIs...

• Redhat OpenJDK 8
• Spring Boot v2.2.4
• Spring Framework v5.2.3.RELEASE
• Hibernate v5.4.11.Final
• JPA v2.0
• Maven v3.6.3
• Gradle v6.1.1
• IntelliJ Idea v2019.3.2

Running the Spring Boot Application

There are couple of ways to run a Spring Boot Application. During development, the ideal one would be to run the main class which is annotated with SpringBootApplication i.e, CrudCatalogueApplication.java in this project. And the other ways are running through maven or gradle.

Run the application using Maven

Use the below command to run the Spring Boot application using Maven

~:\> mvn clean spring-boot:run

Run the application using Gradle

Use the below command to run the Spring Boot application using Gradle

~:\> gradle clean bootRun

Run the application using java -jar command

To run the application using java -jar command, we need to generate the package. Below are the maven and gradle command to generate the jar for the spring boot application.

~:\> mvn clean package

~:\> java -jar target/catalogue-crud-0.0.1-SNAPSHOT.jar 

~:\> gradle clean build

~:\> java -jar build/libs/catalogue-crud-0.0.1-SNAPSHOT.jar