📚 SpringBoot

📌 JPAの永続コンテキスト

✔持続性コンテキストは何ですか?

アプリケーションとデータベースの間にオブジェクトを格納する論理概念

✔持続性コンテキストの存在原因

📌 掲示板記事の保存(ajaxの再使用)

function writeAticle() {
            $.ajax({
                type: "POST",
                url: "/article",
                contentType: 'application/json; charset=utf-8',
                data: JSON.stringify({content: $("#content").val()}),
                success: function (response) {
                    $("#content").val('');
                    if(confirm("저장된 메시지를 확인하시겠어요?")) {
                        readAticle(response['id'])
                    }
                }
            })
        }

        function readAticle(id) {
            $.ajax({
                type: "GET",
                url: `/article/${id}`,
                success: function (response) {
                    console.log(response['content']);
                    
                    $("#acticle").html(response['content']);
                    //article 태그의 내용을 가져와서 바꿈
                }
            })
        }

package com.sparta.springtest.controller;

import com.sparta.springtest.domain.entity.Board;
import com.sparta.springtest.dto.BoardDto;
import com.sparta.springtest.repository.BoardRepository;

import com.sparta.springtest.service.BoardService;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

import java.util.List;


@RequiredArgsConstructor
@RestController
public class Boardcontroller {

    private final BoardService boardService;

    @PostMapping("/article")
    public Board setBoard(@RequestBody BoardDto boardDto){
        return boardService.setBoard(boardDto);
    }

    @GetMapping("/article/{id}")
    public Board getBoard(@PathVariable Long id){
        return boardService.getBoard(id);
    }
}

package com.sparta.springtest.dto;

import com.sparta.springtest.domain.entity.Board;
import lombok.*;

import java.time.LocalDateTime;

@Getter
@Setter
public class BoardDto {

    private String content;


}

package com.sparta.springtest.service;
import com.sparta.springtest.domain.entity.Board;
import com.sparta.springtest.dto.BoardDto;
import com.sparta.springtest.repository.BoardRepository;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;

import javax.transaction.Transactional;
import java.util.ArrayList;
import java.util.List;

@RequiredArgsConstructor
@Service
public class BoardService {
    private final BoardRepository boardRepository;

    public Board setBoard(BoardDto boardDto){
        Board board = new Board();
        board.setContent(boardDto.getContent()); 
        //boardDto로 받아온 데이터를 board 엔티티에 저장
        boardRepository.save(board);
        
        return board;
    }

    public Board getBoard(Long id){
        return boardRepository.findById(id).get();
    }
}

import lombok.Setter;

import javax.persistence.*;

@Setter
@Getter // get 함수를 일괄적으로 만들어줍니다.
@Entity // DB 테이블 역할을 합니다.
public class Board extends Timestamped {

    // ID가 자동으로 생성 및 증가합니다.
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Id
    private Long id;

    // 반드시 값을 가지도록 합니다.
    @Column(nullable = false)
    private String content;


}

package com.sparta.springtest.repository;


import com.sparta.springtest.domain.entity.Board;
import org.springframework.data.jpa.repository.JpaRepository;

public interface BoardRepository extends JpaRepository<Board, Long> {
}