| 💡 Dynamic Web Project 를 활용한 기본적인 CRUD JSP 게시판을 만들어 보자. |
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>
<h2>게시글 작성</h2>
<form action="create-post" method="post">
<label for="title"> 제목 : </label>
<input type="text" id="title" name="title" value="게시글 제목 1">
<br><br>
<label for="content"> 내용 : </label>
<input type="text" id="content" name="content" value="JSP 웹 프로그래밍 ....">
<button type="submit">글 작성</button>
</form>
<br>
<a href="read-posts">게시글 목록</a>
</body>
</html>
com.tenco.servlet/CreatePostServlet.java
게시글 작성 기능 만들기 (비즈니스 로직 계층)
package com.tenco.servlet;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
@WebServlet("/create-post")
public class CreatePostServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public CreatePostServlet() {
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 기본 값 설정 (언어 설정)
request.setCharacterEncoding("UTF-8");
// HTTP 요청 메시지에서 데이터 추출
String title = request.getParameter("title");
String content = request.getParameter("content");
// 인증 검사 생략(로그인 여부 확인)
// 데이터 유효성 검사는 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>결과 확인 페이지</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><br>
<%-- 게시글 작성 화면으로 이동 --%>
<a href="createPost.jsp"> 게시글 작성 페이지 </a>
<br><br>
<%-- 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 jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
@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("readPosts.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></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>
<%
} else {
%>
<p>작성된 게시글 하나도 없습니다.</p>
<%
}
%>
</body>
</html>
com.tenco.servlet/DeletePostServlet .java
게시글 삭제 기능 만들어 보기 (비즈니스 로직 계층)
package com.tenco.servlet;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
@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");
System.out.println("id : " + id);
try (Connection conn = DBUtil.getConnection() ){
String sql = " DELETE FROM posts WHERE id = ? ";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setInt(1, Integer.parseInt(id));
pstmt.executeUpdate();
// 클라이언트에게 새로운 URL를 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("result.jsp?message=error");
}
}
}
com.tenco.servlet/DetailPostServlet .java
게시글 상세 보기 기능 만들기 (비즈니스 로직 계층)
package com.tenco.servlet;
import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
@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");
}
}
}: request.getRequestDispatcher("detailPost.jsp").forward(request, response); 활용
webapp/detailPost.jsp
게시글 상세보기 화면 (프레젠테이션 계층)
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.sql.ResultSet"%>
<!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");
while(rs.next()) {
%>
<h3><%= rs.getString("title") %></h3>
<p><%= rs.getString("content") %> </p>
<p><%= rs.getString("created_at") %> </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 jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
@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");
// 일반적인 로직 수정 - 권한확인 확인 (세션정보, 작성자 정보 비교)
String id = request.getParameter("boardId");
// SELECT * FROM posts where id = 3; <--- 작성자
// 유효성 검사 (사용자 새로 입력 정보가 유효성 검사)
// Update 구문 처리
// 트랜잭션 처리를 해야 한다. (commit , rollback)
String title = request.getParameter("title");
String content = request.getParameter("content");
try (Connection con = DBUtil.getConnection()) {
String sql = " UPDATE posts SET title = ?, content = ? WHERE id = ? ";
PreparedStatement pstmt = con.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) {
response.sendRedirect("result.jsp?message=error");
}
}
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