BookController.java

package com.example.bookmanagement;

import java.util.List;
import java.util.Optional;

import com.example.bookmanagement.error.BookIdMismatchException;
import com.example.bookmanagement.error.BookNotFoundException;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class BookController {

@Autowired
BookRepository bookRepository;

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

@GetMapping("/getBookById/{id}")
public Optional<Book> getBookById(@PathVariable Long id)
{
  System.out.println(bookRepository.findById(id));
return bookRepository.findById(id);
}

@PostMapping("/addBook")
public Book addBook(@RequestBody Book book)
{
return bookRepository.save(book);
}

@PutMapping("/updateBook/{id}")
public Book updateBook(@PathVariable Long id, @RequestBody Book bookDetails)
{
Optional<Book> book = bookRepository.findById(id);
Book book_new=book.get();
book_new.setAuthor_name(bookDetails.getAuthor_name());
book_new.setBook_name(bookDetails.getBook_name());
book_new.setIsbn(bookDetails.getIsbn());
return bookRepository.save(book_new);

}

@DeleteMapping("/deleteBook/{id}")
public void deleteBook(@PathVariable Long id)
{
Optional<Book> book=bookRepository.findById(id);
Book book_new=book.get();
bookRepository.delete(book_new);
}

}