HTTP requests in SpringBoot

• HTTP Fundamentals
• Used with annotations

// GET - 목록 조회
@GetMapping("/posts")
public List<Post> getPosts() {
    return postService.findAll();
}
 
// POST - 리소스 생성
@PostMapping("/posts")
public void createPost(@RequestBody Post post) {
    postService.save(post);
}
 
// PUT - 리소스 전체 수정
@PutMapping("/posts/{id}")
public void updatePost(@PathVariable Long id, @RequestBody Post post) {
    postService.update(id, post);
}
 
// PATCH - 리소스 일부 수정
@PatchMapping("/posts/{id}")
public void patchPost(@PathVariable Long id, @RequestBody Map<String, Object> updates) {
    postService.patch(id, updates);
}
 
// DELETE - 리소스 삭제
@DeleteMapping("/posts/{id}")
public void deletePost(@PathVariable Long id) {
    postService.delete(id);
}

Status code

@ResponseStatus(HttpStatus.NOT_FOUND)
public class ResourceNotFoundException extends RuntimeException {
    public ResourceNotFoundException(String message) {
        super(message);
    }
}
 
// 또는 ResponseEntity로 명시적 설정
return ResponseEntity.status(HttpStatus.CREATED).body(newUser);

Content-Type, Accept

In Spring Boot, automatic data conversion and serialization are handled based on these two headers.

• When a client sends a request with Content-Type: application/json → Spring Boot automatically converts (deserializes) the JSON in the request body into a Java object.
• The server, according to the Accept: application/json header → serializes the Java object into a JSON string for the response.

Example code

@PostMapping(
    value = "/posts", 
    // Only accepts requests with Content-Type: application/json
    consumes = MediaType.APPLICATION_JSON_VALUE, 
    // Will produce a response with Content-Type: application/json
    produces = MediaType.APPLICATION_JSON_VALUE  
)
public ResponseEntity<Post> createPost(@RequestBody Post post) {
    Post saved = postService.save(post);
    return ResponseEntity.status(HttpStatus.CREATED).body(saved);
}

• @RequestBody deserializes the request body into an object according to the Content-Type header.
• The produces attribute determines the response format and sets the Content-Type header of the response, based on the client’s Accept header.