JSP & Servlet 게시판 구현하기(게시글 목록 조회)

지난번에 게시글 쓰기 기능을 구현 하였다.

https://nullgoyatten.tistory.com/22

JSP & Servlet 게시판 구현하기(게시글 쓰기)

 

이번에는 게시글 목록 조회 기능을 구현하도록 하자.

 

1. ArticleDao 에 selectCount 메서드 추가 (전체 게시글 개수를 구하기 위함)

경로 : article.dao> ArticleDao.java

public int selectCount(Connection conn) throws SQLException {
		Statement stmt = null;
		ResultSet rs = null;
		try {
			stmt = conn.createStatement();
			rs = stmt.executeQuery("select count(*) from article");
			if (rs.next()) {
				return rs.getInt(1);
			}
			return 0;
		} finally {
			JdbcUtil.close(rs);
			JdbcUtil.close(stmt);
		}
	}

2. ArticleDao 에 select메서드 추가(지정한 범위의 게시글을 읽어오기 위함)

위의 

경로 : article.dao> ArticleDao.java

	public List<Article> select(Connection conn, int startRow, int size) throws SQLException {
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			pstmt = conn.prepareStatement("select * from article " +
					"order by article_no desc limit ?, ?");
			pstmt.setInt(1, startRow);
			pstmt.setInt(2, size);
			rs = pstmt.executeQuery();
			List<Article> result = new ArrayList<>();
			while (rs.next()) {
				result.add(convertArticle(rs));
			}
			return result;
		} finally {
			JdbcUtil.close(rs);
			JdbcUtil.close(pstmt);
		}
	}

	private Article convertArticle(ResultSet rs) throws SQLException {
		return new Article(rs.getInt("article_no"),
				new Writer(
						rs.getString("writer_id"),
						rs.getString("writer_name")),
				rs.getString("title"),
				toDate(rs.getTimestamp("regdate")),
				toDate(rs.getTimestamp("moddate")),
				rs.getInt("read_cnt"));
	}

	private Date toDate(Timestamp timestamp) {
		return new Date(timestamp.getTime());
	}
}

3. 위 두 메서드를 추가한 전체 코드는 아래와 같다.

package article.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import article.model.Article;
import article.model.Writer;
import jdbc.JdbcUtil;

public class ArticleDao {

	public Article insert(Connection conn, Article article) throws SQLException {
		PreparedStatement pstmt = null;
		Statement stmt = null;
		ResultSet rs = null;
		try {
			pstmt = conn.prepareStatement("insert into article "
					+ "(writer_id, writer_name, title, regdate, moddate, read_cnt) "
					+ "values (?,?,?,?,?,0)");
			pstmt.setString(1, article.getWriter().getId());
			pstmt.setString(2, article.getWriter().getName());
			pstmt.setString(3, article.getTitle());
			pstmt.setTimestamp(4, toTimestamp(article.getRegDate()));
			pstmt.setTimestamp(5, toTimestamp(article.getModifiedDate()));
			int insertedCount = pstmt.executeUpdate();

			if (insertedCount > 0) {
				stmt = conn.createStatement();
				rs = stmt.executeQuery("select last_insert_id() from article");
				if (rs.next()) {
					Integer newNo = rs.getInt(1);
					return new Article(newNo,
							article.getWriter(),
							article.getTitle(),
							article.getRegDate(),
							article.getModifiedDate(),
							0);
				}
			}
			return null;
		} finally {
			JdbcUtil.close(rs);
			JdbcUtil.close(stmt);
			JdbcUtil.close(pstmt);
		}
	}

	private Timestamp toTimestamp(Date date) {
		return new Timestamp(date.getTime());
	}
	
	public int selectCount(Connection conn) throws SQLException {
		Statement stmt = null;
		ResultSet rs = null;
		try {
			stmt = conn.createStatement();
			rs = stmt.executeQuery("select count(*) from article");
			if (rs.next()) {
				return rs.getInt(1);
			}
			return 0;
		} finally {
			JdbcUtil.close(rs);
			JdbcUtil.close(stmt);
		}
	}
	
	public List<Article> select(Connection conn, int startRow, int size) throws SQLException {
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		try {
			pstmt = conn.prepareStatement("select * from article " +
					"order by article_no desc limit ?, ?");
			pstmt.setInt(1, startRow);
			pstmt.setInt(2, size);
			rs = pstmt.executeQuery();
			List<Article> result = new ArrayList<>();
			while (rs.next()) {
				result.add(convertArticle(rs));
			}
			return result;
		} finally {
			JdbcUtil.close(rs);
			JdbcUtil.close(pstmt);
		}
	}

	private Article convertArticle(ResultSet rs) throws SQLException {
		return new Article(rs.getInt("article_no"),
				new Writer(
						rs.getString("writer_id"),
						rs.getString("writer_name")),
				rs.getString("title"),
				toDate(rs.getTimestamp("regdate")),
				toDate(rs.getTimestamp("moddate")),
				rs.getInt("read_cnt"));
	}

	private Date toDate(Timestamp timestamp) {
		return new Date(timestamp.getTime());
	}
}

 

4. ArticlePage 작성 (게시글 목록을 제공하는 서비스 클래스를 구현하기 위해 데이터와 페이징 정보를 담을 곳이 필요하다.)

경로 : article.service > ArticlePage.java

package article.service;

import java.util.List;

import article.model.Article;

public class ArticlePage {

	private int total;
	private int currentPage;
	private List<Article> content;
	private int totalPages;
	private int startPage;
	private int endPage;

	public ArticlePage(int total, int currentPage, int size, List<Article> content) {
		this.total = total;
		this.currentPage = currentPage;
		this.content = content;
		if (total == 0) {
			totalPages = 0;
			startPage = 0;
			endPage = 0;
		} else {
			totalPages = total / size;
			if (total % size > 0) {
				totalPages++;
			}
			int modVal = currentPage % 5;
			startPage = currentPage / 5 * 5 + 1;
			if (modVal == 0) startPage -= 5;
			
			endPage = startPage + 4;
			if (endPage > totalPages) endPage = totalPages;
		}
	}

	public int getTotal() {
		return total;
	}

	public boolean hasNoArticles() {
		return total == 0;
	}

	public boolean hasArticles() {
		return total > 0;
	}
	
	public int getCurrentPage() {
		return currentPage;
	}

	public int getTotalPages() {
		return totalPages;
	}

	public List<Article> getContent() {
		return content;
	}

	public int getStartPage() {
		return startPage;
	}
	
	public int getEndPage() {
		return endPage;
	}
}

 

5. ListArticleService 작성 (게시글 목록을 제공하는 서비스 클래스를 구현.)

경로 : article.service > ListArticleService.java

package article.service;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

import article.dao.ArticleDao;
import article.model.Article;
import jdbc.connection.ConnectionProvider;

public class ListArticleService {

	private ArticleDao articleDao = new ArticleDao();
	private int size = 10;

	public ArticlePage getArticlePage(int pageNum) {
		try (Connection conn = ConnectionProvider.getConnection()) {
			int total = articleDao.selectCount(conn);
			List<Article> content = articleDao.select(
					conn, (pageNum - 1) * size, size);
			return new ArticlePage(total, pageNum, size, content);
		} catch (SQLException e) {
			throw new RuntimeException(e);
		}
	}
}

6. ListArticleHandler 작성

경로 : article.command > ListArticleHandler.java

package article.command;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import article.service.ArticlePage;
import article.service.ListArticleService;
import mvc.command.CommandHandler;

public class ListArticleHandler implements CommandHandler {

	private ListArticleService listService = new ListArticleService();

	@Override
	public String process(HttpServletRequest req, HttpServletResponse res) 
			throws Exception {
		String pageNoVal = req.getParameter("pageNo");
		int pageNo = 1;
		if (pageNoVal != null) {
			pageNo = Integer.parseInt(pageNoVal);
		}
		ArticlePage articlePage = listService.getArticlePage(pageNo);
		req.setAttribute("articlePage", articlePage);
		return "/WEB-INF/view/listArticle.jsp";
	}

}

 

7. commandHandlerURI.properties 수정. ListArticleHandler가 /article/list.do 요청을 처리하도록 매핑 설정에 추가한다. 

/join.do=member.command.JoinHandler
/login.do=auth.command.LoginHandler
/logout.do=auth.command.LogoutHandler
/changePwd.do=member.command.ChangePasswordHandler
/article/write.do=article.command.WriteArticleHandler
/article/list.do=article.command.ListArticleHandler

8. listArticle.jsp 작성

경로 :  WebContent > WEB-INF > view > listArticle.jsp

<%@ page language="java" contentType="text/html; charset=EUC-KR"
    pageEncoding="EUC-KR"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=EUC-KR">
<title>게시글 목록</title>
</head>
<body>

<table border="1">
	<tr>
		<td colspan="4"><a href="write.do">[게시글쓰기]</a></td>
	</tr>
	<tr>
		<td>번호</td>
		<td>제목</td>
		<td>작성자</td>
		<td>조회수</td>
	</tr>
<c:if test="${articlePage.hasNoArticles()}">
	<tr>
		<td colspan="4">게시글이 없습니다.</td>
	</tr>
</c:if>
<c:forEach var="article" items="${articlePage.content}">
	<tr>
		<td>${article.number}</td>
		<td>
		<a href="read.do?no=${article.number}&pageNo=${articlePage.currentPage}">
		<c:out value="${article.title}"/>
		</a>
		</td>
		<td>${article.writer.name}</td>
		<td>${article.readCount}</td>
	</tr>
</c:forEach>
<c:if test="${articlePage.hasArticles()}">
	<tr>
		<td colspan="4">
			<c:if test="${articlePage.startPage > 5}">
			<a href="list.do?pageNo=${articlePage.startPage - 5}">[이전]</a>
			</c:if>
			<c:forEach var="pNo" 
					   begin="${articlePage.startPage}" 
					   end="${articlePage.endPage}">
			<a href="list.do?pageNo=${pNo}">[${pNo}]</a>
			</c:forEach>
			<c:if test="${articlePage.endPage < articlePage.totalPages}">
			<a href="list.do?pageNo=${articlePage.startPage + 5}">[다음]</a>
			</c:if>
		</td>
	</tr>
</c:if>
</table>
</body>
</html>

 

9. web.xml 수정

web.xml(경로 : WebContent > WEB-INF)에 LoginCheckFilter 설정(list.do)을 추가해줘야 한다.

<!-- LoginCheckFilter관련 설정 -->
	<filter>
		<filter-name>LoginCheckFilter</filter-name>
		<filter-class>filter.LoginCheckFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>LoginCheckFilter</filter-name>
		<url-pattern>/changePwd.do</url-pattern>
		<url-pattern>/article/list.do</url-pattern>
		<url-pattern>/article/write.do</url-pattern>
	</filter-mapping>
<!-- LoginCheckFilter관련 설정 -->

 

10. 테스트(http://localhost:8080/board/article/list.do)

 

다음글 : 게시글 내용 조회 구현

https://nullgoyatten.tistory.com/26

JSP & Servlet 게시판 구현하기(게시글 내용 조회)