JSP

간단한 게시판 만들기

DDG9 2024. 7. 15. 17:15

프로젝트 구성 확인

 

 

webapp/createPost.jsp

게시글 작성 화면 만들어 보기 (프레젠테이션 계층)

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>게시글 작성</title>
<link rel="stylesheet" type="text/css" href="css/styles.css">
</head>
<body>
	<div class="create">
		<h2>게시글 작성</h2>
		<form action="create-post" method="post">	
			<input class="title" type="text" id="title" name="title" value="게시글 제목 1">
			<br><br>
			<textarea class="content" rows="45" cols="88" id="content" name="content">게시글 내용 1</textarea>
			<br><br>
			<button type="submit">글 작성</button>
		<button type="button"><a href="read-posts">게시글 목록</a></button>
		</form>
	</div>
</body>
</html>

 

 

com.tenco.servlet/CreatePostServlet.java

게시글 작성 기능 만들기 (비즈니스 로직 계층)

package com.tenco.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;

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

@WebServlet("/create-post")
public class CreatePostServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public CreatePostServlet() {
		super();
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");

		// HTTP 요청 메세지에서 데이터 추출
		String title = request.getParameter("title");
		String content = request.getParameter("content");

		// 인증 검사 생략 (로그인 여부 확인)
		// 데이터 유효성 검사 생략...

		try (Connection conn = DBUtil.getConnection()) {
			String sql = " INSERT INTO posts(title, content) VALUES (?, ?) ";
			PreparedStatement pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, title);
			pstmt.setString(2, content);
			pstmt.executeUpdate();
			response.sendRedirect("result.jsp?message=create-success");
		} catch (Exception e) {
			e.printStackTrace();
			response.sendRedirect("result.jsp?message=error");
		}
	}
}

 

 

webapp/result.jsp

결과 확인 페이지 만들어 보기

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h2>결과 확인 페이지</h2>
	<%
		String message = request.getParameter("message");
		if("create-success".equals(message)) {
			out.println("<p>게시글 작성에 성공</p>");
		} else if ("delete-success".equals(message)) {
			out.println("<p>게시글 삭제에 성공</p>");
		} else if ("update=success".equals(message)) {	
			out.println("<p>게시글 수정에 성공</p>");
		} else {
			out.println("<p>작업에 실패</p>");
		}
	%>
	<br>
	<!-- 게시글 작성 화면으로 이동 -->
	<a href="createPost.jsp">게시글 작성 페이지</a>
	
	<!-- 게시글 목록 화면으로 이동 -->
	<a href="read-posts">게시글 리스트 페이지</a>
</body>
</html>

 

 

com.tenco.servlet/DBUtil.java

DB 접근 객체 만들어 보기 (기본)

package com.tenco.servlet;

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

public class DBUtil {
	private static final String URL = "jdbc:mysql://localhost:3306/demo6?serverTimezone=Asia/Seoul";
	private static final String USER = "root";
	private static final String PASSWORD = "asd123";

	public static Connection getConnection() throws ClassNotFoundException, SQLException {
		Class.forName("com.mysql.cj.jdbc.Driver");
		return DriverManager.getConnection(URL, USER, PASSWORD);
	}
}

 

 

com.tenco.servlet/ReadPostsServlet .java

게시글 목록 기능 만들기 (비즈니스 로직 계층)

package com.tenco.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

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

@WebServlet("/read-posts")
public class ReadPostsServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public ReadPostsServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 응답 처리 MIME TYPE 설정
		response.setContentType("text/html;charset=UTF-8");
		try (Connection conn = DBUtil.getConnection()) {
			String sql = " SELECT * FROM posts ORDER BY created_at DESC ";
			PreparedStatement pstmt = conn.prepareStatement(sql);
			ResultSet rs = pstmt.executeQuery();

			request.setAttribute("resultSet", rs);
			request.getRequestDispatcher("readPosts2.jsp").forward(request, response);

		} catch (Exception e) {
			e.printStackTrace();
		}
	}
}

request.getRequestDispatcher("readPosts.jsp").forward(request, response); 활용

 

 

webapp/readPost.jsp

게시글 목록 화면 만들어 보기 (프레젠테이션 계층)

<%@page import="java.sql.ResultSet"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>게시글 목록</title>
<link rel="stylesheet" type="text/css" href="css/styles.css">
</head>
<body>
	<h2>게시글 목록</h2>
	<%	
		ResultSet rs = (ResultSet) request.getAttribute("resultSet");
		if(rs != null) {
	%>
		<table border="1">
			<tr>
				<th>ID</th>
				<th>제목</th>
				<th>내용</th>
				<th>작성일자</th>
				<th>액션</th>
			</tr>
			<%
				while(rs.next()) {
			%>
			<tr>
				<td><%=rs.getInt("id") %></td>
				<td><a href="view-post?boardId=<%=rs.getInt("id") %>"><%=rs.getString("title") %></a></td>
				<td><%=rs.getString("content") %></td>
				<td><%=rs.getString("created_at") %></td>
				<td>
					<form action="delete-post" method="get">
						<input type="hidden" name="boardId" value=<%=rs.getInt("id") %>>
						<button type="submit">삭제</button>
					</form>
				</td>
			</tr>
			<% } %>
		</table>
		<a href="createPost.jsp">글쓰기</a>
	<% } else { %>
		<p>작성된 게시글이 하나도 없습니다.</p>
	<% } %>
</body>
</html>

 

 

com.tenco.servlet/DeletePostServlet .java

게시글 삭제 기능 만들어 보기 (비즈니스 로직 계층)

package com.tenco.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;

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

@WebServlet("/delete-post")
public class DeletePostServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public DeletePostServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		String id = request.getParameter("boardId");
		String sql = " DELETE FROM posts WHERE id = ? ";
		try (Connection conn = DBUtil.getConnection()) {
			PreparedStatement pstmt = conn.prepareStatement(sql);
			pstmt.setInt(1, Integer.parseInt(id));
			pstmt.executeUpdate();

			// 클라이언트에게 새로운 URL을 자동으로 요청하도록 HTTP 응답을 보낸다.
			// HTTP 상태 코드 302(임시 이동) 사용자에게 새로운 URL로 이동처리 시킨다.
			response.sendRedirect("result.jsp?message=delete-success");
		} catch (Exception e) {
			e.printStackTrace();
			response.sendRedirect("reuslt.jsp?message=error");
		}
	}
}

 

 

com.tenco.servlet/DetailPostServlet .java

게시글 상세 보기 기능 만들기 (비즈니스 로직 계층)

package com.tenco.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

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

@WebServlet("/view-post")
public class DetailPostServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public DetailPostServlet() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.setContentType("text/html;charset=UTF-8");
		String id = request.getParameter("boardId");

		try (Connection conn = DBUtil.getConnection()) {
			String sql = " SELECT * FROM posts WHERE id = ? ";
			PreparedStatement pstmt = conn.prepareStatement(sql);
			pstmt.setInt(1, Integer.parseInt(id));
			ResultSet rs = pstmt.executeQuery();
			
			request.setAttribute("resultSet", rs);
			request.getRequestDispatcher("detailPost.jsp").forward(request, response);
			
		} catch (Exception e) {
			e.printStackTrace();
			response.sendRedirect("result.jsp?message=error");
		}
	}
}

 

 

webapp/detailPost.jsp

게시글 상세보기 화면 (프레젠테이션 계층)

<%@page import="java.sql.ResultSet"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>게시글 상세보기 화면</title>
</head>
<body>
	<h2>상세보기 화면</h2>
	<%
		ResultSet rs = (ResultSet) request.getAttribute("resultSet");
		if(rs.next()){
	%>
		<h3><%= rs.getString("title")%></h3>
		<p><%= rs.getString("content")%></p>
		<p><small><%=rs.getString("created_at") %></small></p>
		<br><br><br>

		<!-- 수정 폼 -->
		<h3>게시글 수정</h3>
		<form action="update-post" method="post">
		<input type="hidden" name = "boardId" value="<%=rs.getInt("id") %>">
		<label for="title">제목 : </label>
		<input type="text" id="title" name="title" value="<%=rs.getString("title") %>">
		<br><br>
		<label for="content">내용 : </label>
		<input type="text" id="content" name="content" value="<%=rs.getString("content") %>">
		<br><br>
		<button type="submit">수정하기</button>
		</form>	
	<% } %>
</body>
</html>

 

 

com.tenco.servlet/UpdatePostServlet.java

게시글 수정 기능 만들기 (비즈니스 로직 계층)

package com.tenco.servlet;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;

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

@WebServlet("/update-post")
public class UpdatePostServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public UpdatePostServlet() {
		super();
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		String id = request.getParameter("boardId");
		// 권한 확인 일반적인 로직
		// SELECT * FROM posts WHERE id = ?
		// 작성자 정보 / 세션정보의 유저ID값 을 확인해서 같다면
		
		// 유효성 검사
		
		// Update 구문 처리
		// 트랜잭션 처리를 해야한다. (commit, rollback)
		String title = request.getParameter("title");
		String content = request.getParameter("content");
		try (Connection conn = DBUtil.getConnection()) {
			String sql = " UPDATE posts SET title=?, content=? WHERE id=? ";
			PreparedStatement pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, title);
			pstmt.setString(2, content);
			pstmt.setInt(3, Integer.parseInt(id));
			pstmt.executeUpdate();
			
			response.sendRedirect("result.jsp?message=update=success");
		} catch (Exception e) {
			e.printStackTrace();
			response.sendRedirect("result.jsp?message=error");
		}
	}
}

 

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