MySQL 데이터 이클립스에서 사용

데이터를 가져와서 어떻게 쓰는지 전체적으로 돌아가는 구조를 보기 위함

 

 

MainApplication 클래스

import java.util.*;
import database.DAO.BoardDAO;
import database.Entity.BoardEntity;

public class MainApplication {
	
	public static void main(String[] args) {
		// DAO 인스턴스 생성
		BoardDAO dao = new BoardDAO();
		// DB에서 Board 테이블의 전체 레코드를 검색해서 출력
		List<BoardEntity> findResult = dao.find();
		
		for(BoardEntity entity : findResult) System.out.println(entity.toString());
		
	}
}

 

 

BoardDAO 클래스

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.*;

import database.DataBaseConnector;
import database.Entity.BoardEntity;
import dto.InsertBoardDTO;

// DAO : Data Access Object
// DB에 접근해서 데이터 검색 및 삽입 등의 DB 작업을 담당하는 클래스
public class BoardDAO {
	
	// DB의 Board 테이블에서 모든 컬럼을 선택해서 반환하는 메서드
	// SQL : SELECT * FROM Board;
	// 예상되는 반환 결과는 0개 이상의 복수의 레코드
	public List<BoardEntity> find(){
		List<BoardEntity> result = new ArrayList<BoardEntity>();
		
		final String SQL = "SELECT * FROM Board";
		Connection connection = null;
		Statement statement = null;
		ResultSet resultSet = null;	
		
		try {
			// DB 접근은 try catch 안에
			connection = DataBaseConnector.createConnection();
			statement = connection.createStatement();
			resultSet = statement.executeQuery(SQL);	

			while(resultSet.next()) {
				Integer id = resultSet.getInt(1);
				String boardTitle = resultSet.getString(2);
				String boardContent = resultSet.getString(3);
				String boardDateTime = resultSet.getString(4);
				Integer boardLike = resultSet.getInt(5);
				Integer boardWriter = resultSet.getInt(6);
			
				BoardEntity entity = new BoardEntity(id, boardTitle, boardContent, boardDateTime, boardLike, boardWriter);
			    result.add(entity);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if(connection != null && !connection.isClosed()) {
					connection.close();
				}
				if(statement != null && !statement.isClosed())
					statement.close();
				if(resultSet != null && !resultSet.isClosed())
					resultSet.close();
				
			} catch (Exception e2) {
				e2.printStackTrace();
			}
			
		}
		
		return result;
		
	}
  }

 

 

BoardEntity 클래스

// Entity : DB의 테이블과 서로 매핑되는 JAVA CLASS
// 목적 : DB 테이블의 레코드를 각각의 레코드를 인스턴스로 받기 위한 용도
// 조건 : DB 테이블의 각 컬럼명, 데이터 타입과 Entity 클래스의 필드명, 데이터 타입이 일치해야함
public class BoardEntity {
	private Integer id; 
	private String boardTitle;
	private String boardContent;
	private String boardDateTime; 
	private Integer boardLike;
	private Integer boardWriter;
	
	
	public BoardEntity(Integer id, String boardTitle, String boardContent, String boardDateTime, Integer boardLike,
			Integer boardWriter) {
		this.id = id;
		this.boardTitle = boardTitle;
		this.boardContent = boardContent;
		this.boardDateTime = boardDateTime;
		this.boardLike = boardLike;
		this.boardWriter = boardWriter;
	}
	
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	
	public String getBoardTitle() {
		return boardTitle;
	}
	public void setBoardTitle(String boardTitle) {
		this.boardTitle = boardTitle;
	}
	
	public String getBoardContent() {
		return boardContent;
	}
	public void setBoardContent(String boardContent) {
		this.boardContent = boardContent;
	}
	
	public String getBoardDateTime() {
		return boardDateTime;
	}
	public void setBoardDateTime(String boardDateTime) {
		this.boardDateTime = boardDateTime;
	}
	
	public Integer getBoardLike() {
		return boardLike;
	}
	public void setBoardLike(Integer boardLike) {
		this.boardLike = boardLike;
	}
	
	public Integer getBoardWriter() {
		return boardWriter;
	}
	public void setBoardWriter(Integer boardWriter) {
		this.boardWriter = boardWriter;
	}

	@Override
	public String toString() {
		return "BoardEntity [id=" + id + ", boardTitle=" + boardTitle + ", boardContent=" + boardContent
				+ ", boardDateTime=" + boardDateTime + ", boardLike=" + boardLike + ", boardWriter=" + boardWriter
				+ "]";
	}

}

 

 

InsertBoardDTO 클래스

public class InsertBoardDTO {
	
	private String boardTitle;
	private String boardContent;
	private Integer boardWriter;
	
	public InsertBoardDTO(String boardTitle, String boardContent, Integer boardWriter) {
		super();
		this.boardTitle = boardTitle;
		this.boardContent = boardContent;
		this.boardWriter = boardWriter;
	}
	
	public String getBoardTitle() {
		return boardTitle;
	}
	public void setBoardTitle(String boardTitle) {
		this.boardTitle = boardTitle;
	}
	public String getBoardContent() {
		return boardContent;
	}
	public void setBoardContent(String boardContent) {
		this.boardContent = boardContent;
	}
	public Integer getBoardWriter() {
		return boardWriter;
	}
	public void setBoardWriter(Integer boardWriter) {
		this.boardWriter = boardWriter;
	}
	
	@Override
	public String toString() {
		return "InsertBoardDTO [boardTitle=" + boardTitle + ", boardContent=" + boardContent + ", boardWriter="
				+ boardWriter + "]";
	}

	
}

 

 

DataBaseConnector 클래스

import java.sql.Connection;
import java.sql.DriverManager;

public class DataBaseConnector {
	
    private static final String DATABASE_URL = "jdbc:mysql://127.0.0.1:3306/peed";
	private static final String USER_NAME = "root";
	private static final String USER_PASSWORD = "root";
	
	public static Connection createConnection() {
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
			
			return DriverManager.getConnection(DATABASE_URL, USER_NAME, USER_PASSWORD);
		} catch (Exception e) {
			return null;
		}
		
	}
	
}