API Development with Spring Boot

When it comes to creating REST APIs, Spring Boot provides a powerful and convenient framework to handle the complexities of API development.

Spring Boot and REST APIs

Spring Boot makes it easy to create RESTful services. REST (Representational State Transfer) is an architectural style that uses HTTP as the communication protocol between clients and servers. It allows clients to perform CRUD (Create, Read, Update, Delete) operations on resources with simple HTTP methods such as GET, POST, PUT, PATCH, and DELETE.

Creating a REST Controller

To create a REST API in Spring Boot, you need to define a controller class and annotate it with @RestController. The @RestController annotation combines the functionality of the @Controller and @ResponseBody annotations, making it easier to develop RESTful APIs.

Here's an example of a UserController class that handles HTTP requests for a User resource:

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@RestController

@RequestMapping("/api")

public class UserController {

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    private UserService userService;

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    @Autowired

    public UserController(UserService userService) {

        this.userService = userService;

    }

​

    @GetMapping

    public List<User> getAllUsers() {

        return userService.getAllUsers();

    }

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    @GetMapping("/{id}")

    public User getUserById(@PathVariable Long id) {

        return userService.getUserById(id);

    }

​

    @PostMapping

    public User createUser(@RequestBody User user) {

        return userService.createUser(user);

    }

​

    @PutMapping("/{id}")

    public User updateUser(@PathVariable Long id, @RequestBody User user) {

        return userService.updateUser(id, user);