Getting Started with Spring Boot: Your First REST API in 15 Minutes

Spring Boot has revolutionized Java development by making it incredibly easy to create production-ready applications. In this tutorial, we'll build a simple REST API for managing books in just 15 minutes!

Prerequisites

Before we begin, make sure you have:

• Java 17 or later installed
• Your favorite IDE (IntelliJ IDEA, Eclipse, or VS Code)
• Basic knowledge of Java

Step 1: Setting Up the Project

Visit Spring Initializr and create a new project with these settings:

• Project: Maven
• Language: Java
• Spring Boot: 3.2.0
• Group: com.example
• Artifact: bookapi
• Dependencies: Spring Web, Spring Data JPA, H2 Database

Click "Generate" and extract the downloaded zip file.

Step 2: Create the Book Model

Create a new class Book.java in src/main/java/com/example/bookapi/model:

package com.example.bookapi.model;

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.Id;

@Entity
public class Book {
    @Id
    @GeneratedValue
    private Long id;
    private String title;
    private String author;
    private String isbn;

    // Getters and Setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getTitle() { return title; }
    public void setTitle(String title) { this.title = title; }
    public String getAuthor() { return author; }
    public void setAuthor(String author) { this.author = author; }
    public String getIsbn() { return isbn; }
    public void setIsbn(String isbn) { this.isbn = isbn; }
}

Step 3: Create the Repository

Create BookRepository.java in src/main/java/com/example/bookapi/repository:

package com.example.bookapi.repository;

import com.example.bookapi.model.Book;
import org.springframework.data.jpa.repository.JpaRepository;

public interface BookRepository extends JpaRepository<Book, Long> {
}

Step 4: Create the REST Controller

Create BookController.java in src/main/java/com/example/bookapi/controller:

package com.example.bookapi.controller;

import com.example.bookapi.model.Book;
import com.example.bookapi.repository.BookRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/books")
public class BookController {

    @Autowired
    private BookRepository bookRepository;

    @GetMapping
    public List<Book> getAllBooks() {
        return bookRepository.findAll();
    }

    @PostMapping
    public Book createBook(@RequestBody Book book) {
        return bookRepository.save(book);
    }

    @GetMapping("/{id}")
    public Book getBook(@PathVariable Long id) {
        return bookRepository.findById(id)
            .orElseThrow(() -> new RuntimeException("Book not found"));
    }
}

Step 5: Configure the Application

Update src/main/resources/application.properties:

spring.datasource.url=jdbc:h2:mem:bookdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.h2.console.enabled=true

Testing the API

Start your application by running the main class BookapiApplication. You can now test the API using curl or Postman:

Create a new book:

curl -X POST http://localhost:8080/api/books \
     -H "Content-Type: application/json" \
     -d '{"title":"Spring Boot in Action","author":"Craig Walls","isbn":"978-1617292545"}'

Get all books:

curl http://localhost:8080/api/books

Next Steps

Now that you have a basic REST API running, you might want to explore:

1. Adding validation to your endpoints
2. Implementing proper error handling
3. Adding Swagger/OpenAPI documentation
4. Implementing service layer for business logic
5. Adding unit and integration tests

Conclusion

In just 15 minutes, we've created a functional REST API using Spring Boot. This demonstrates how Spring Boot's convention-over-configuration approach and auto-configuration features make it incredibly easy to get started with web development in Java.

The complete source code for this tutorial is available on GitHub.

Remember, this is just the beginning of what you can do with Spring Boot. Stay tuned for more advanced tutorials!