REST Api

Creating a REST API in Java can be achieved using frameworks like Spring Boot, which simplifies development and setup. Below is a detailed guide to building a REST API for managing books using Spring Boot.

restVsSoap

Prerequisites:

    Java Development Kit (JDK): Ensure JDK 11 or higher is installed.

    Maven: Build tool for managing dependencies and building the project.

    Spring Boot: A popular framework for creating RESTful services.

Steps to Create a REST API

1. Setup a Spring Boot Project

You can create a Spring Boot project using:

    Spring Initializr

    Your IDE (e.g., IntelliJ IDEA or Eclipse)

Include the following dependencies:

    Spring Web: For building REST APIs.

    Spring Boot DevTools (Optional): For live reload during development.

Maven Dependency Configuration (pom.xml)

    <dependencies>

 <dependency> 

  <groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-web</artifactId> 

  </dependency>

<dependency>

<groupId>org.springframework.boot</groupId> 

  <artifactId>spring-boot-devtools</artifactId>

<scope>runtime</scope> 

  </dependency> 

</dependencies>

2. Code Example: A Simple REST API

Directory Structure

css:

src/main/java/com/example/bookapi

Book Entity

java

package com.example.bookapi.model;

public class Book {
    private int id;
    private String title;
    private String author;

    // Constructors
    public Book() {}

    public Book(int id, String title, String author) {
        this.id = id;
        this.title = title;
        this.author = author;
    }

    // Getters and Setters
    public int getId() {
        return id;
    }

    public void setId(int 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;
    }
}

BookController

java code:

package com.example.bookapi.controller;

import com.example.bookapi.model.Book;
import org.springframework.web.bind.annotation.*;

import java.util.ArrayList;
import java.util.List;

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

    private final List<Book> books = new ArrayList<>();

    public BookController() {
        books.add(new Book(1, "1984", "George Orwell"));
        books.add(new Book(2, "To Kill a Mockingbird", "Harper Lee"));
        books.add(new Book(3, "The Great Gatsby", "F. Scott Fitzgerald"));
    }

    // Get all books
    @GetMapping
    public List<Book> getBooks() {
        return books;
    }

    // Get a book by ID
    @GetMapping("/{id}")
    public Book getBook(@PathVariable int id) {
        return books.stream()
                .filter(book -> book.getId() == id)
                .findFirst()
                .orElseThrow(() -> new RuntimeException("Book not found"));
    }

    // Add a new book
    @PostMapping
    public Book addBook(@RequestBody Book book) {
        book.setId(books.size() + 1);
        books.add(book);
        return book;
    }

    // Update a book
    @PutMapping("/{id}")
    public Book updateBook(@PathVariable int id, @RequestBody Book updatedBook) {
        Book book = books.stream()
                .filter(b -> b.getId() == id)
                .findFirst()
                .orElseThrow(() -> new RuntimeException("Book not found"));

        book.setTitle(updatedBook.getTitle());
        book.setAuthor(updatedBook.getAuthor());
        return book;
    }

    // Delete a book
    @DeleteMapping("/{id}")
    public String deleteBook(@PathVariable int id) {
        books.removeIf(book -> book.getId() == id);
        return "Book deleted successfully";
    }
}

Main Application:
java code:
package com.example.bookapi;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class BookApiApplication {
    public static void main(String[] args) {
        SpringApplication.run(BookApiApplication.class, args);
    }
}
How to Run the Application:
    
1.Build and Run
    Navigate to the project directory.
    Use Maven to run the application:
    bash mvn spring-boot:run
2.Access the API The API will be available at http://localhost:8080/books.

Testing the API
1.Get all books
Endpoint: GET /books
Example response:
json
[
  {"id": 1, "title": "1984", "author": "George Orwell"},
  {"id": 2, "title": "To Kill a Mockingbird", "author": "Harper Lee"}
]
2.Get a specific book
Endpoint: GET /books/1
Response:
json {"id": 1, "title": "1984", "author": "George Orwell"}
similarly you can perform other api tesing.
Enhancements
Database Integration: Use a database (e.g., MySQL, PostgreSQL) instead of in-memory storage.
Validation: Add validation for inputs using @Valid.
Error Handling: Add custom exceptions for better error messages.
Authentication: Secure the API using OAuth or JWT.
Let me know if you'd like help with any specific enhancement