@PutMapping and @DeleteMapping in Spring Boot - Mini Project: Build & Apply

Using @PutMapping and @DeleteMapping in Spring Boot

📖 Scenario: You are building a simple Spring Boot REST API to manage a list of books in a library. You want to allow users to update book details and delete books using HTTP methods.

🎯 Goal: Create a Spring Boot controller with endpoints to update a book's information using @PutMapping and delete a book using @DeleteMapping.

📋 What You'll Learn

Create a Book class with id, title, and author fields.

Create a BookController class with a list of books as initial data.

Add a @PutMapping method to update a book by id.

Add a @DeleteMapping method to delete a book by id.

💡 Why This Matters

🌍 Real World

Updating and deleting resources via REST APIs is common in web applications like library systems, inventory management, and user profiles.

💼 Career

Understanding @PutMapping and @DeleteMapping is essential for backend developers working with Spring Boot to build RESTful services.

1

Create initial book data

Create a BookController class with a List<Book> called books initialized with these exact books: new Book(1, "1984", "George Orwell") and new Book(2, "Brave New World", "Aldous Huxley").

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.ArrayList;

@RestController
public class BookController {
    // Your code here
}

Need a hint?

Use List.of() inside new ArrayList<>() to create the initial list.

2

Add a configuration variable for book count

Inside BookController, add a private integer variable called nextId and set it to 3 to track the next book ID.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.ArrayList;

@RestController
public class BookController {
    private List books = new ArrayList(List.of(
        new Book(1, "1984", "George Orwell"),
        new Book(2, "Brave New World", "Aldous Huxley")
    ));
    // Your code here
}

Need a hint?

Declare nextId as a private integer and assign it the value 3.

3

Add @PutMapping method to update a book

Add a method annotated with @PutMapping("/books/{id}") named updateBook that takes @PathVariable int id and @RequestBody Book updatedBook. Use a for loop with variables book and update the matching book's title and author if book.getId() == id. Return the updated book.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.ArrayList;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;

@RestController
public class BookController {
    private List books = new ArrayList(List.of(
        new Book(1, "1984", "George Orwell"),
        new Book(2, "Brave New World", "Aldous Huxley")
    ));
    private int nextId = 3;

    // Your code here
}

Need a hint?

Use @PutMapping with path /books/{id}. Loop through books to find the book with matching id and update its fields.

4

Add @DeleteMapping method to delete a book

Add a method annotated with @DeleteMapping("/books/{id}") named deleteBook that takes @PathVariable int id. Use a for loop with index i to find the book with matching id and remove it from books. Return void.

Spring Boot

import org.springframework.web.bind.annotation.RestController;
import java.util.List;
import java.util.ArrayList;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.DeleteMapping;

@RestController
public class BookController {
    private List books = new ArrayList(List.of(
        new Book(1, "1984", "George Orwell"),
        new Book(2, "Brave New World", "Aldous Huxley")
    ));
    private int nextId = 3;

    @PutMapping("/books/{id}")
    public Book updateBook(@PathVariable int id, @RequestBody Book updatedBook) {
        for (Book book : books) {
            if (book.getId() == id) {
                book.setTitle(updatedBook.getTitle());
                book.setAuthor(updatedBook.getAuthor());
                return book;
            }
        }
        return null;
    }

    // Your code here
}

Need a hint?

Use @DeleteMapping with path /books/{id}. Loop with index to find and remove the book.