TIL(Today I Learned)
: 매일 저녁, 하루를 마무리하며 작성 !
: ⭕ 지식 위주, 학습한 것을 노트 정리한다고 생각하고 작성하면서 머리 속 흩어져있는 지식들을 정리 !
알고리즘 코드카타
- 문제 설명
어떤 문장의 각 알파벳을 일정한 거리만큼 밀어서 다른 알파벳으로 바꾸는 암호화 방식을 시저 암호라고 합니다. 예를 들어 "AB"는 1만큼 밀면 "BC"가 되고, 3만큼 밀면 "DE"가 됩니다. "z"는 1만큼 밀면 "a"가 됩니다. 문자열 s와 거리 n을 입력받아 s를 n만큼 민 암호문을 만드는 함수, solution을 완성해 보세요.
- 제한사항
공백은 아무리 밀어도 공백입니다.
s는 알파벳 소문자, 대문자, 공백으로만 이루어져 있습니다.
s의 길이는 8000이하입니다.
n은 1 이상, 25이하인 자연수입니다.
class Solution {
public String solution(String s, int n) {
String answer = "";
for(int i=0; i<s.length(); i++) {
char ch = s.charAt(i);
if(Character.isLowerCase(ch)) {
ch = (char) ((ch - 'a' + n) % 26 + 'a');
} else if(Character.isUpperCase(ch)) {
ch = (char) ((ch - 'A' + n) % 26 + 'A');
}
answer += ch;
}
return answer;
}
}
팀 프로젝트 진행
뉴스 피드 프로젝트 Post CRUD 구현
// PostController
package com.sparta.wildcard_newsfeed.domain.post.controller;
import com.sparta.wildcard_newsfeed.domain.comment.dto.CommentResponseDto;
import com.sparta.wildcard_newsfeed.domain.comment.dto.PostWithCommentsResponseDto;
import com.sparta.wildcard_newsfeed.domain.comment.service.CommentService;
import com.sparta.wildcard_newsfeed.domain.common.CommonResponseDto;
import com.sparta.wildcard_newsfeed.domain.post.dto.PostRequestDto;
import com.sparta.wildcard_newsfeed.domain.post.dto.PostResponseDto;
import com.sparta.wildcard_newsfeed.domain.post.service.PostService;
import com.sparta.wildcard_newsfeed.security.AuthenticationUser;
import io.swagger.v3.oas.annotations.Operation;
import io.swagger.v3.oas.annotations.media.Content;
import io.swagger.v3.oas.annotations.media.Schema;
import io.swagger.v3.oas.annotations.responses.ApiResponse;
import io.swagger.v3.oas.annotations.responses.ApiResponses;
import io.swagger.v3.oas.annotations.tags.Tag;
import jakarta.validation.Valid;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.security.core.annotation.AuthenticationPrincipal;
import org.springframework.web.bind.annotation.*;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
@Slf4j
@RestController
@RequiredArgsConstructor
@RequestMapping("/api/v1/post")
@Tag(name = "Post 컨트롤러", description = "Post API")
public class PostController {
private final PostService postService;
private final CommentService commentService;
// 게시물 등록
@PostMapping
@Operation(summary = "게시물 등록")
@ApiResponses({
@ApiResponse(responseCode = "200", description = "게시물 등록 성공",
content = @Content(mediaType = "application/json",
schema = @Schema(implementation = CommonResponseDto.class)))
})
public ResponseEntity<CommonResponseDto<PostResponseDto>> addPost(
@AuthenticationPrincipal AuthenticationUser user,
@Valid @RequestBody PostRequestDto postRequestDto
) {
PostResponseDto postResponseDto = postService.addPost(postRequestDto, user);
return ResponseEntity.ok()
.body(CommonResponseDto.<PostResponseDto>builder()
.statusCode(HttpStatus.OK.value())
.message("게시물 등록 성공")
.data(postResponseDto)
.build());
}
// 게시물 전체 조회
@GetMapping
@Operation(summary = "게시물 전체 조회")
@ApiResponses({
@ApiResponse(responseCode = "200", description = "게시물 전체 조회 성공",
content = @Content(mediaType = "application/json",
schema = @Schema(implementation = CommonResponseDto.class)))
})
public ResponseEntity<CommonResponseDto<Object>> findAll() {
List<PostResponseDto> posts = postService.findAll();
return ResponseEntity.ok()
.body(CommonResponseDto.builder()
.statusCode(HttpStatus.OK.value())
.message("게시물 전체 조회 성공")
.data(posts)
.build());
}
// // 게시물 단일 조회 + 해당 게시물에 달린 댓글 전체 조회
@GetMapping("/{postId}")
@Operation(summary = "게시물 단일 조회")
@ApiResponses({
@ApiResponse(responseCode = "200", description = "게시물 단일 조회 성공",
content = @Content(mediaType = "application/json",
schema = @Schema(implementation = CommonResponseDto.class)))
})
public ResponseEntity<CommonResponseDto<PostWithCommentsResponseDto>> findById(@PathVariable(name = "postId") long id) {
// 게시물 단일 조회
PostResponseDto post = postService.findById(id);
// 해당 게시물에 달린 댓글 전체 조회
List<CommentResponseDto> comments = commentService.findAllCommentsByPostId(id);
// Post와 Comments를 하나의 객체로 병합
PostWithCommentsResponseDto postWithCommentsResponse = new PostWithCommentsResponseDto(post, comments);
return ResponseEntity.ok()
.body(CommonResponseDto.<PostWithCommentsResponseDto>builder()
.statusCode(HttpStatus.OK.value())
.message("게시물 단일 조회, 댓글 조회 성공")
.data(postWithCommentsResponse)
.build());
}
//게시물 수정
@PutMapping("/{postId}")
@Operation(summary = "게시물 수정")
@ApiResponses({
@ApiResponse(responseCode = "200", description = "게시물 수정 성공",
content = @Content(mediaType = "application/json",
schema = @Schema(implementation = CommonResponseDto.class)))
})
public ResponseEntity<CommonResponseDto<PostResponseDto>> updatePost(
@AuthenticationPrincipal AuthenticationUser user,
@Valid @RequestBody PostRequestDto postRequestDto,
@PathVariable Long postId
) {
PostResponseDto postResponseDto = postService.updatePost(postRequestDto, postId, user);
return ResponseEntity.ok()
.body(CommonResponseDto.<PostResponseDto>builder()
.statusCode(HttpStatus.OK.value())
.message("게시물 수정 성공")
.data(postResponseDto)
.build());
}
//게시물 삭제
@DeleteMapping("/{postId}")
@Operation(summary = "게시물 삭제")
@ApiResponses({
@ApiResponse(responseCode = "200", description = "게시물 삭제 성공",
content = @Content(mediaType = "application/json",
schema = @Schema(implementation = CommonResponseDto.class)))
})
public ResponseEntity<CommonResponseDto<PostResponseDto>> deletePost(
@AuthenticationPrincipal AuthenticationUser user,
@Valid @PathVariable Long postId
) {
postService.deletePost(postId, user);
return ResponseEntity.ok()
.body(CommonResponseDto.<PostResponseDto>builder()
.statusCode(HttpStatus.OK.value())
.message("게시물 삭제 성공")
.build());
}
}
// PostRequestDto
package com.sparta.wildcard_newsfeed.domain.post.dto;
import io.swagger.v3.oas.annotations.media.Schema;
import jakarta.validation.constraints.NotBlank;
import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
@Getter
@NoArgsConstructor
@AllArgsConstructor
public class PostRequestDto {
@Schema(description = "게시물 제목", example = "제목")
@NotBlank(message = "제목은 필수 입력 값입니다.")
private String title;
@Schema(description = "게시물 내용", example = "내용")
@NotBlank(message = "내용은 필수 입력 값입니다.")
private String content;
}
// PostResponseDto
package com.sparta.wildcard_newsfeed.domain.post.dto;
import com.sparta.wildcard_newsfeed.domain.post.entity.Post;
import lombok.Getter;
import java.time.LocalDateTime;
@Getter
public class PostResponseDto {
private Long id;
private String title;
private String content;
private String username;
private LocalDateTime createdAt;
private LocalDateTime updatedAt;
public PostResponseDto(Post post) {
this.id = post.getId();
this.title = post.getTitle();
this.content = post.getContent();
this.username = post.getUser().getName();
this.createdAt = post.getCreatedAt();
this.updatedAt = post.getUpdatedAt();
}
}
// Post
package com.sparta.wildcard_newsfeed.domain.post.entity;
import com.sparta.wildcard_newsfeed.domain.common.TimeStampEntity;
import com.sparta.wildcard_newsfeed.domain.post.dto.PostRequestDto;
import com.sparta.wildcard_newsfeed.domain.user.entity.User;
import jakarta.persistence.*;
import lombok.AccessLevel;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
@Getter
@Setter
@Entity
@NoArgsConstructor(access = AccessLevel.PUBLIC)
public class Post extends TimeStampEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
@ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
@JoinColumn(name = "user_id", nullable = false)
private User user;
@Column(nullable = false)
private String title;
@Column(nullable = false)
private String content;
public Post(PostRequestDto postRequestDto, User user) {
this.user = user;
this.title = postRequestDto.getTitle();
this.content = postRequestDto.getContent();
}
public void update(PostRequestDto postRequestDto) {
this.title = postRequestDto.getTitle();
this.content = postRequestDto.getContent();
}
}
// PostRepository
package com.sparta.wildcard_newsfeed.domain.post.repository;
import com.sparta.wildcard_newsfeed.domain.post.entity.Post;
import com.sparta.wildcard_newsfeed.domain.user.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import java.util.Optional;
public interface PostRepository extends JpaRepository<Post, Long> {
Optional<Post> findPostById(Long postId);
}
// PostService
package com.sparta.wildcard_newsfeed.domain.post.service;
import com.sparta.wildcard_newsfeed.domain.post.dto.PostRequestDto;
import com.sparta.wildcard_newsfeed.domain.post.dto.PostResponseDto;
import com.sparta.wildcard_newsfeed.domain.post.entity.Post;
import com.sparta.wildcard_newsfeed.domain.post.repository.PostRepository;
import com.sparta.wildcard_newsfeed.domain.user.entity.User;
import com.sparta.wildcard_newsfeed.domain.user.repository.UserRepository;
import com.sparta.wildcard_newsfeed.security.AuthenticationUser;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.Comparator;
import java.util.List;
@Slf4j
@Service
@RequiredArgsConstructor
public class PostService {
private final PostRepository postRepository;
private final UserRepository userRepository;
@Transactional
public PostResponseDto addPost(PostRequestDto postRequestDto, AuthenticationUser user) {
User byUsercode = userRepository.findByUsercode(user.getUsername())
.orElseThrow(() -> new IllegalArgumentException("사용자를 찾을 수 없습니다."));
Post post = new Post(postRequestDto, byUsercode);
postRepository.save(post);
return new PostResponseDto(post);
}
public PostResponseDto findById(long id) {
Post post = findPostById(id);
return new PostResponseDto(post);
}
public List<PostResponseDto> findAll() {
List<Post> postlist = postRepository.findAll();
return postlist.stream()
.sorted(Comparator.comparing(Post::getCreatedAt).reversed())
.map(PostResponseDto::new)
.toList();
}
@Transactional
public PostResponseDto updatePost(PostRequestDto postRequestDto, Long postId, AuthenticationUser user) {
Post post = findPostById(postId);
validateUser(post, user);
post.update(postRequestDto);
postRepository.save(post);
return new PostResponseDto(post);
}
@Transactional
public void deletePost(Long postId, AuthenticationUser user) {
Post post = findPostById(postId);
validateUser(post, user);
postRepository.delete(post);
}
private Post findPostById(long id) {
return postRepository.findById(id)
.orElseThrow(() -> new IllegalArgumentException("해당 게시물이 존재하지 않습니다."));
}
private void validateUser(Post post, AuthenticationUser user) {
if (!post.getUser().getUsercode().equals(user.getUsername())) {
throw new IllegalArgumentException("작성자만 할 수 있습니다.");
}
}
}
야옹