Spring Boot Backend Development Course, Prerequisite Knowledge API and REST API

Prior Knowledge: API and REST API

To learn Spring Boot (SPB) backend development, it is important to first understand the concepts of API (Application Programming Interface) and REST API (Representational State Transfer API). In this article, we will explain the basic concepts and workings of API and REST API in detail.

What is an API?

An API is an interface that defines the interaction between software and software. In other words, it provides a way for developers to access or request specific functionalities. APIs can exist in various forms and are commonly used in web, mobile, and cloud applications.

Types of APIs

  • Web API: An API that can usually be accessed via the HTTP protocol. It facilitates data transmission between the client and server.
  • Library API: An API implemented to fit a specific programming language, used directly within the code.
  • Operating System API: An API that allows applications to call functions of the operating system.

What is a REST API?

A REST API is a type of web API that follows the REST architectural style. REST is an architectural style proposed by Roy Fielding in 2000, defining a method for transferring the state of resources in a client-server structure.

Characteristics of REST

  • Stateless: Each request is independent, and the server does not store the state of previous requests or client information.
  • Resource-Based: Everything is represented as a resource, and resources are accessed through URIs.
  • Representations: Representations of resources are transmitted between client and server and can be delivered in formats such as JSON and XML.
  • Uniform Interface: Interaction between client and server occurs through clearly defined interfaces.

HTTP Methods

REST APIs use HTTP methods to perform CRUD (Create, Read, Update, Delete) operations on resources. Commonly used HTTP methods include:

  • GET: Retrieves a resource.
  • POST: Creates a new resource.
  • PUT: Modifies an existing resource.
  • DELETE: Deletes a resource.

Advantages of REST API

REST APIs offer several advantages:

  • Flexibility: Data can be utilized from various clients, making it widely used in web and mobile applications.
  • Scalability: Since clients and servers are independent, scaling the server does not affect the client.
  • Simplicity: Based on the HTTP protocol, it is easy to use and understand.

Implementing REST API in Spring Boot

Spring Boot is a framework that allows for easy implementation of REST APIs. Below is an example of how to create a simple REST API using Spring Boot.

1. Add Dependencies

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
}

2. Create Controller

Create a controller that represents a simple REST API.

import org.springframework.web.bind.annotation.*;

    @RestController
    @RequestMapping("/api/items")
    public class ItemController {

        @GetMapping
        public List getAllItems() {
            // Return all items
        }

        @PostMapping
        public Item createItem(@RequestBody Item item) {
            // Create a new item
        }

        // Other methods...
    }

3. Run the Application

Run the Spring Boot application to use the REST API.

Conclusion

APIs and REST APIs are essential foundational knowledge for Spring Boot backend development. Through APIs, one can interact with various software, and using REST APIs allows for the construction of simple and efficient web services. We hope this course helps you build deeper Spring Boot development knowledge.