Spring Boot REST API Book Management - Interview Guide

A complete Spring Boot project demonstrating REST API concepts, perfect for interview preparation.

🎯 Project Overview

This project implements a Book Management System with complete CRUD operations using Spring Boot.

🔑 Key Concepts Covered

1. REST API Basics

• @RestController: Used in bookcontroller.java for handling REST requests
• HTTP Methods Implementation:
  • GET: Fetch books
  • POST: Add new books
  • PUT: Update books
  • DELETE: Remove books

2. Project Structure

bootrestbook/
├── controllers/
│   └── bookcontroller.java    # Handles HTTP requests
├── services/
│   └── BookService.java       # Business logic
└── entities/
    └── Book.java             # Data model

3. Key Annotations Used

• @RestController: Marks class as REST controller
• @GetMapping: Handles GET requests
• @PostMapping: Handles POST requests
• @PutMapping: Handles PUT requests
• @DeleteMapping: Handles DELETE requests
• @RequestBody: Converts JSON to Java objects
• @PathVariable: Extracts values from URL

4. Important Interview Concepts

REST API Design

• Each endpoint follows REST conventions
• Proper HTTP methods for CRUD operations
• Meaningful URL patterns (/books, /books/{id})

Service Layer Pattern

• Separation of concerns
• Business logic in service layer
• Controller only handles request/response

Data Flow

1. Client sends HTTP request
2. Controller receives request
3. Service processes data
4. Response returned to client

📝 Interview Questions & Answers

Q1: What is the difference between @Controller and @RestController?

• @Controller: Traditional MVC controller, returns view names
• @RestController: Combines @Controller and @ResponseBody, returns data directly

Q2: Explain the role of @RequestBody

• Converts JSON/XML from request body to Java objects
• Used in POST/PUT methods to receive data
• Requires proper getters/setters in entity class

Q3: Why do we use Service layer?

• Separates business logic from controllers
• Enables code reusability
• Makes testing easier
• Follows Single Responsibility Principle

Q4: Explain your project's CRUD operations

1. Create (POST):

   @PostMapping("/books")
   public Book addBook(@RequestBody Book book)

2. Read (GET):

   @GetMapping("/books")
   public List<Book> getBooks()

3. Update (PUT):

   @PutMapping("/books/{bookId}")
   public Book updateBook(@RequestBody Book book)

4. Delete (DELETE):

   @DeleteMapping("/books/{bookId}")
   public void deleteBook(@PathVariable("bookId") int bookId)

🔄 Database Integration (Next Steps)

• Adding JPA dependencies
• Configuring MySQL database
• Creating proper entity mappings
• Implementing JPA Repository

📚 Best Practices Demonstrated

1. Proper package structure
2. Service layer implementation
3. Clear naming conventions
4. Separation of concerns

🛠️ How to Run

1. Clone the repository
2. Run mvn spring-boot:run
3. Access endpoints at http://localhost:8080/books

🧪 Testing API

Use Postman to test:

• GET http://localhost:8080/books
• POST http://localhost:8080/books with JSON body
• PUT http://localhost:8080/books/{id}
• DELETE http://localhost:8080/books/{id}