2021-10-26 (Springboot - JPA - CRUD(4) )

JPA를 활용해 CRUD 기능을 만들어보자

4. 글 수정

BoardJpaController

@PutMapping(value = "/{id}")
    public ApiResponse<BoardDTO> putBoard(@PathVariable int id,
                                          @RequestBody BoardDTO boardDTO){
        Board data = boardJpaService.putBoard(id, boardDTO);
        return new ApiResponse(true, data);
    }

Board

package kr.ac.daegu.springbootapi.boardjpa.model;

import lombok.*;

import javax.persistence.*;
import java.sql.Date;
import java.sql.Time;
import java.time.LocalDate;
import java.time.LocalTime;

@Entity
@Getter
@Setter
@Table(name = "board")
@ToString
@NoArgsConstructor(access = AccessLevel.PROTECTED)
@Builder
public class Board {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name = "author")
    private String author;
    @Column(name = "subject")
    private String subject;
    @Column(name = "content")
    private String content;

    @Column(name = "writeDate")
    private LocalDate writeDate;
    @Column(name = "writeTime")
    private LocalTime writeTime;
    @Column(name = "readCount")
    private Integer readCount;
    @Column(name = "commentCount")
    private Integer commentCount;
    @Column(name = "password")
    private String password;
    @Column(name = "replyRootId")
    private Integer replyRootId;
    @Column(name = "depth")
    private Integer depth;
    @Column(name = "orderNum")
    private Integer orderNum;
    @Column(name = "isDel")
    private String isDel;

    public Board(Integer id,
                 String author,
                 String subject,
                 String content,
                 LocalDate writeDate,
                 LocalTime writeTime,
                 Integer readCount,
                 Integer commentCount,
                 String password,
                 Integer replyRootId,
                 Integer depth,
                 Integer orderNum,
                 String isDel) {
        this.id = id;
        this.author = author;
        this.subject = subject;
        this.content = content;
        this.writeDate = writeDate;
        this.writeTime = writeTime;
        this.readCount = readCount;
        this.commentCount = commentCount;
        this.password = password;
        this.replyRootId = replyRootId;
        this.depth = depth;
        this.orderNum = orderNum;
        this.isDel = isDel;
    }
}

- @setter 추가

BoardRepository

Optional<Board> findBoardById(int id);

- @Optional

 > Java8에서는 Optional<T> 클래스를 사용해 NPE를 방지할 수 있도록 도와준다. Optional<T>는 null이 올 수 있는 값을 감싸는 Wrapper 클래스로, 참조하더라도 NPE가 발생하지 않도록 도와준다. Optional 클래스는 아래와 같은 value에 값을 저장하기 때문에 null이더라도 바로 NPE가 발생하지 않으며, 클래스이기 때문에 각종 메소드를 제공해준다.

 > NPE(NullPountException)

  - 개발을 할 때 가장 많이 발생하는 예외 중 하나
출처: https://mangkyu.tistory.com/70 [MangKyu's Diary]

 

BoardJpaService

public Board putBoard(int id, BoardDTO boardDTO) {
        Optional<Board> boardData = boardRepository.findBoardById(id);

        // 람다식을 사용하여
        boardData.ifPresent(selectedBoard -> {
            selectedBoard.setAuthor(boardDTO.getAuthor());
            selectedBoard.setSubject(boardDTO.getSubject());
            selectedBoard.setContent(boardDTO.getContent());
            selectedBoard.setPassword(boardDTO.getPassword());
            boardRepository.save(selectedBoard);
        });

        return boardData.orElseGet(boardData::get);
    }

- 람다식개념 참고사이트

https://mangkyu.tistory.com/113