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MVC Pattern 이해하기

by 댕꼬 2022. 3. 23.

MVC Pattern (Model-View-Controller)

MVC패턴이란

MVC 는 Model, View, Controller의 약자로, 프로젝트를 구성할 때 그 구성요소를 세가지의 역할로 구분한 패턴이다. 

 

  • Model : Logic(Business & DB)을 처리하기 위한 모든 것, controller로 부터 넘어온 data를 이용하여 이를 수행하고 그에 대한 결과를 다시 conteoller에 return한다.  (DAO, Service)
  • View : 모든 화면 처리를 담당. Client의 요청에 대한 결과뿐 아니라 controller에 요청을 보내는 화면단도 jsp에서 처리한다. Logic처리를 위한 java code는 사라지고 결과 출력을 위한 code만 존재 (JSP)
  • Controller : Client의 요청을 분석하여 Logic처리응 위한 Model단을 호툴한다. return 받은 결과data를 필요에 따라 request, session등에 저장하고 redirect 또는 forward 방식으로 jsp(view) page를 이용하여 출력한다. (Servlet)

출처 : 오픈튜토리얼
Model 2 구조 - MVC 패턴

[실습예제]

서점 도서관리프로그램 (Book 객체 CURD)

 

BookVO.java

package vo;

import java.io.Serializable;

public class BookVO implements Serializable{
	
	private int bookno; // NUMBER(4) PRIMARY KEY,
	private String title; // VARCHAR2(40),
	private String publisher; // VARCHAR2(40),
	private int price; // NUMBER(8)
	
	public BookVO() {	}

	public BookVO(int bookno, String title, String publisher, int price) {
		this.bookno = bookno;
		this.title = title;
		this.publisher = publisher;
		this.price = price;
	}

	public int getBookno() {
		return bookno;
	}

	public void setBookno(int bookno) {
		this.bookno = bookno;
	}

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	public String getPublisher() {
		return publisher;
	}

	public void setPublisher(String publisher) {
		this.publisher = publisher;
	}

	public int getPrice() {
		return price;
	}

	public void setPrice(int price) {
		this.price = price;
	}

	@Override
	public String toString() {
		return "BookVO [bookno=" + bookno + ", title=" + title + ", publisher=" + publisher + ", price=" + price + "]";
	}

	
}

 

BooKDAO.java

package dao;

import java.util.List;

import vo.BookVO;

public interface BookDAO {
	 List<BookVO> bookList();
	 void bookAdd(BookVO vo);
	 void deleteBook(int bookno);
	 void updateBook(BookVO vo);
	 BookVO getBook(int no) ;

	 List<BookVO> searchBook(String condition,String keyword);
}

BookDAOImple.java

package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

import util.DBUtil;
import vo.BookVO;

public class BookDAOImpl implements BookDAO{

	public List<BookVO> bookList() {
		List<BookVO> list = new ArrayList<BookVO>();
		String sql = "select * from book order by bookno desc";
		             //"select * from book order by bookno desc limit 1 , 3"

		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		
		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			rs = ps.executeQuery();
			while(rs.next()) {
				BookVO b = new BookVO();
				b.setBookno(rs.getInt("bookno"));
				b.setPrice(rs.getInt("price"));
                b.setPublisher(rs.getString("publisher"));
                b.setTitle(rs.getString("title"));
                list.add(b);
			}
			
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}
		return list;
	}

	public void bookAdd(BookVO vo) {
        String sql = "insert into book (title,publisher,price) " + 
        		"values (?,?,?)";
		
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		
		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			
			ps.setString(1, vo.getTitle());
			ps.setString(2, vo.getPublisher());
			ps.setInt(3, vo.getPrice());
			
			int i = ps.executeUpdate();
			if(i == 0) throw new Exception("등록 실패");
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}
	}
	public BookVO getBook(int no) {
		String sql = "select * from book where bookno = ?";
		
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		BookVO b = null;
		
		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setInt(1, no);
			rs = ps.executeQuery();
			while(rs.next()) {
				b = new BookVO();
				b.setBookno(rs.getInt("bookno"));
				b.setPrice(rs.getInt("price"));
                b.setPublisher(rs.getString("publisher"));
                b.setTitle(rs.getString("title"));
			}
			
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}
		return b;
	}

	public void deleteBook(int bookno) {
        String sql = "delete from book where bookno = ?";
		
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		
		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setInt(1, bookno);
			
			int i = ps.executeUpdate();
			if(i == 0) throw new Exception("삭제 오류 발생 ");
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}		
	}

	@Override
	public void updateBook(BookVO vo) {
		// TODO Auto-generated method stub
		String sql  = "UPDATE Book SET price = ?  WHERE bookno = ?";
		
		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		int result = 0;

		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			// ? 세팅
			ps.setInt(1, vo.getPrice());
			ps.setInt(2, vo.getBookno());
			
			//실행 및 결과값 핸들링
            result = ps.executeUpdate();
            
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}
		
	}

	public List<BookVO> searchBook(String condition, String keyword) {
		List<BookVO> list = new ArrayList<BookVO>();

        String sql = "select * from Book where "+condition+" like ?  order by bookno desc";
        //select * from Book where publisher like '%한%' order by bookno desc;
        //select * from Book where publisher like concat('%','한','%') order by bookno desc;

		Connection con = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		
		try {
			con = DBUtil.getConnection();
			ps = con.prepareStatement(sql);
			ps.setString(1,"%"+ keyword+"%");
			
			rs = ps.executeQuery();
            while (rs.next()) {
				BookVO vo = new BookVO();
				vo.setBookno(rs.getInt("bookno"));
				vo.setTitle(rs.getString("title"));
				vo.setPublisher(rs.getString("publisher"));
				vo.setPrice(rs.getInt("price"));
				list.add(vo);
			}
			
		} catch (Exception e) {
			System.out.println(e);
		}finally {
			DBUtil.close(rs,ps,con);
		}
		
		return list;
	}
}

BookService.java

package service;

import java.util.List;

import vo.BookVO;

public interface BookService {
	
	 List<BookVO> bookList();
	 void bookAdd(BookVO vo);
	 void deleteBook(int bookno);
	 void updateBook(BookVO vo);
	 BookVO getBook(int no) ;

	 List<BookVO> searchBook(String condition,String keyword);
}

BookServiceImpl.java

package service;

import java.util.List;

import dao.BookDAO;
import vo.BookVO;

public class BookServiceImpl implements BookService{
    private BookDAO dao = null;
	
	public BookServiceImpl() {	}
	public BookServiceImpl(BookDAO dao) {
		this.dao = dao;
	}
	public BookDAO getDao() {
		return dao;
	}
	public void setDao(BookDAO dao) {
		this.dao = dao;
	}
	
	@Override
	public List<BookVO> bookList() {
		return dao.bookList();
	}
	@Override
	public void bookAdd(BookVO vo) {
		dao.bookAdd(vo);
	}
	@Override
	public void deleteBook(int bookno) {
		// TODO Auto-generated method stub
		dao.deleteBook(bookno);
	}
	@Override
	public void updateBook(BookVO vo) {
		// TODO Auto-generated method stub
		dao.updateBook(vo);
	}
	@Override
	public List<BookVO> searchBook(String condition, String keyword) {
		// TODO Auto-generated method stub
		return dao.searchBook(condition, keyword);
	}
	@Override
	public BookVO getBook(int no) {
		// TODO Auto-generated method stub
		return dao.getBook(no);
	}

}

 

ListBookServlet.java (도서조회)

package servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import dao.BookDAO;
import dao.BookDAOImpl;
import service.BookService;
import service.BookServiceImpl;
import vo.BookVO;

@WebServlet({ "/ListBookServlet", "/bookList.do" })
public class ListBookServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	protected void service(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
		
		request.setCharacterEncoding("utf-8");
		response.setContentType("text/html;charset=UTF-8");
		
		BookDAO dao = new BookDAOImpl();
		BookService service = new BookServiceImpl(dao);
		
		List<BookVO> list = service.bookList();
		
		request.setAttribute("booklist", list);	
		String page = "/booklist.jsp";
		
		getServletContext().getRequestDispatcher(page).forward(request, response); 
//		request.getRequestDispatcher(page).forward(request, response);	.
		

		
		
	
	
	}

}

booklist.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>book list</title>
<link rel="stylesheet" href="./css/my.css">
<link rel="stylesheet" href="./css/main.css">
</head>
<body>
	<%@ include file="common/header.jsp"%>
	<section>

		<h1>Book List ${pageContext.request.contextPath}</h1>
		<form method="post" action="/ex_00/search.do">
			<div style="text-align: center">
				<select name = "condition">
					<option value ="title">도서제목</option>
					<option value ="publisher">출판사</option>
				</select> 
				<input type="text" name="keyword">
				<button type="submit">검색</button>
			</div>
		</form>
		<br>

		<form method="post" action="/ex_00/deleteBook.do">
			<table>
				<tr>
					<th>bookno</th>
					<th>title</th>
					<th>publisher</th>
					<th>price</th>
					<th><button type="submit">삭제</button></th>
				</tr>
				<c:forEach var="data" items="${booklist}">
					<tr>
						<td>${data.bookno}</td>
						<td><a href="viewBook.do?bookno=${data.bookno}">${data.title}</a>
						</td>
						<td>${data.publisher}</td>
						<td>${data.price}</td>
						<td><input type="checkbox" name="bookno"
							value="${data.bookno}"></td>
					</tr>
				</c:forEach>
			</table>
		</form>
	</section>
	<%@ include file="common/footer.jsp"%>
</body>
</html>

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