[ Java / JSP ] 게시판 및 페이지넘버 댓글기능 구현

OS : Ubuntu 18.04 LTS

Java Version : OpenJDK 1.8.0

DB Version : 8.0.14

Tomcat Version : 8.5

개발툴 : Eclipse

MVC2방식으로 구성하였습니다.

프로젝트 구성

현재 DB구성 

auto_increment를 사용하여 board_num을 자동증가 시켰습니다. mysql의 내장함수인 now()를 사용하여 board_data에 저장합니다. auto_increment는 쉽게 숫자를 자동으로 입력해주지만 중간에 숫자 하나를 삭제하게 되면 삭제된 숫자를 뛰어넘어 다음 수를 입력하게 됩니다. 그 단점을 보안하기 위해 BoardDAO에 재정렬메소드를 정의하였습니다. comment테이블에는 auto_increment를 사용하지 않고 grub이란 수를 계속 증가 시켰습니다. 

BoardBean.java

package Model;
 
public class BoardBean {
    private int board_num;        //글번호
    private String board_name;    //작성자
    private String board_subject;//제목
    private String board_content;//내용
    private int readcount;        //조회수
    private String board_date;    //작성일
    private String board_id;        //작성자 아이디
    
    public int getBoard_num() {
        return board_num;
    }
    public void setBoard_num(int board_num) {
        this.board_num = board_num;
    }
    public String getBoard_name() {
        return board_name;
    }
    public void setBoard_name(String board_name) {
        this.board_name = board_name;
    }
    public String getBoard_subject() {
        return board_subject;
    }
    public void setBoard_subject(String board_subject) {
        this.board_subject = board_subject;
    }
    public String getBoard_content() {
        return board_content;
    }
    public void setBoard_content(String board_content) {
        this.board_content = board_content;
    }
    public int getReadcount() {
        return readcount;
    }
    public void setReadcount(int readcount) {
        this.readcount = readcount;
    }
    public String getBoard_date() {
        return board_date;
    }
    public void setBoard_date(String board_date) {
        this.board_date = board_date;
    }
    public String getBoard_id() {
        return board_id;
    }
    public void setBoard_id(String board_id) {
        this.board_id = board_id;
    }
}

게시글 구성목록을 BoardBean.java에 정의함 

pageInfo.java

package Model;
 
public class pageInfo {
    
    private boolean preve; //이전 페이지
    private boolean next;    //다음페이지
    private int startPage=1;    //시작페이지
    private int endPage;        //마지막페이지
    private int currentPage;        //현재페이지
    private int boardSize = 10; //게시판 사이즈
    private int startRow;        //게시판 첫 시작 번호
    private int listCount;    //게시물 전체 갯수
    private int allPage;        //페이지 전체 갯수
    
    
    
    public int getStartRow() {
        return startRow;
    }
    public void setStartRow(int currentPage) {
        this.startRow = (currentPage - 1) * boardSize;
    }
    public int getCurrentPage() {
        return currentPage;
    }
    public void setCurrentPage(int currentPage) {
        this.currentPage = currentPage;
    }
    public int getListCount() {
        return listCount;
    }
    public void setListCount(int listCount) {
        this.listCount = listCount;
    }
    public int getEndPage() {
        return endPage;
    }
    public void setEndPage(int currentPage, int allPage) {
        if(currentPage == allPage) {
            this.endPage = allPage;
        }else if((currentPage + 4) >= allPage) {
            this.endPage = allPage;
        }else {
            this.endPage = currentPage + 4;
        }
    }
    public int getStartPage() {
        return startPage;
    }
    public void setStartPage(int startPage) {
        this.startPage = startPage;
    }
    public int getAllPage() {
        return allPage;
    }
    public void setAllPage(int listCount) {
        if((listCount & boardSize) > 0) {
            this.allPage = (listCount / boardSize) + 1;
        } else {
            this.allPage = listCount / boardSize ;
        }
    }
    public boolean isPreve() {
        return preve;
    }
    public void setPreve(int currentPage) {
        if(currentPage == 1) {
            this.preve = false;
        } else {
            this.preve = true;
        }
    }
    public boolean isNext() {
        return next;
    }
    public void setNext(int currentPage, int allPage) {
        if(currentPage == allPage ) {
            this.next = false;
        } else {
            this.next = true;
        }
    }
}
 

페이지넘버링 boardSize에 10을 줘서 한 페이지당 10개의 게시글이 보이고 제일 처음으로 자유게시판을 클릭시 null을 받기에 메인콘에서 null일 경우 currentpage는 1이 되어 첫번째 페이지에 10개의 게시글을 보여줌. preve는 currentpage가 1일때 false를 넘겨 보여지지 않게 만들었고 next는 반대로 마지막 페이지 일때 false값을 넘겨줘 보여지지 않게 설정하였음. DAO에서 Alllist메소드를 생성하여 전체 게시글을 가져와 BoardBean으로 값을 넘겨주면 bean에서 계산하여 값을 다시 넘겨주고 main에서 그값을 프론트로 넘겨줍니다. 페이지넘버링이 처음에 이해와 구성이 어려웠음.하지만 가장 재밌는 부분이 아닐까 함.

MainCon.java

package controller;
 
import java.io.IOException;
import java.util.ArrayList;
 
import javax.servlet.RequestDispatcher;
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 javax.servlet.http.HttpSession;
 
import Model.BoardBean;
import Model.BoardDAO;
import Model.CommentBean;
import Model.pageInfo;
 
/**
 * Servlet implementation class MainCon
 */
@WebServlet("*.Pro")
public class MainCon extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public MainCon() {
        super();
        // TODO Auto-generated constructor stub
    }
 
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        reqPro(request, response);
    }
 
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        reqPro(request, response);
    }
    
    protected void reqPro(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        request.setCharacterEncoding("UTF-8");
        String RequestURI = request.getRequestURI();
        String contextPath = request.getContextPath();
        String command = RequestURI.substring(contextPath.length());
        
        
        if(command.equals("/Main.Pro")) {
            HttpSession session = request.getSession();
            session.invalidate();
            response.sendRedirect("index.jsp");
            
        }else if(command.equals("/FreeBoard.Pro")) {
            pageInfo pginfo = new pageInfo();
            ArrayList<BoardBean> bean = new ArrayList<>();
            BoardDAO dbao = new BoardDAO();
            String PageNum = request.getParameter("PageNum");
            if (PageNum == null) {PageNum = "1";}
            pginfo.setCurrentPage(Integer.parseInt(PageNum));
            pginfo.setListCount(dbao.getAllCount());
            pginfo.setStartRow(pginfo.getCurrentPage());
            pginfo.setPreve(pginfo.getCurrentPage());
            pginfo.setAllPage(pginfo.getListCount());
            pginfo.setEndPage(pginfo.getCurrentPage(), pginfo.getAllPage());
            pginfo.setNext(pginfo.getCurrentPage(), pginfo.getAllPage());
            int StartRow = pginfo.getStartRow();
            bean = dbao.getAllList(StartRow);
            request.setAttribute("bean", bean);
            request.setAttribute("pageInfo", pginfo);
            RequestDispatcher dis = request.getRequestDispatcher("FreeBoard.jsp");
            dis.forward(request, response);
            
        } else if(command.equals("/BoardWrite.Pro")) {
            BoardBean bean = new BoardBean();
            BoardDAO dbao = new BoardDAO();
            bean.setBoard_name(request.getParameter("board_name"));
            bean.setBoard_subject(request.getParameter("board_subject"));
            bean.setBoard_content(request.getParameter("board_content"));
            bean.setBoard_id(request.getParameter("board_id"));
            dbao.BoardInsert(bean);
            RequestDispatcher dis = request.getRequestDispatcher("FreeBoard.Pro");
            dis.forward(request, response);
            
        } else if(command.equals("/BoardInfo.Pro")) {
            System.out.println(request.getParameter("boardnum1"));
            int num = Integer.parseInt(request.getParameter("boardnum"));
            ArrayList<BoardBean> bean = new ArrayList<>();
            ArrayList<CommentBean> cbean = new ArrayList<>();
            BoardDAO dbao = new BoardDAO();
            dbao.readCountup(num);
            bean = dbao.getOneBoardInfo(num);
            cbean = dbao.getOneComment(num);
            request.setAttribute("bean", bean);
            request.setAttribute("cbean", cbean);
            RequestDispatcher dis = request.getRequestDispatcher("ReadBoardPage.jsp");
            dis.forward(request, response);
            
        } else if(command.equals("/BoardDelete.Pro")) {
            BoardDAO dbao = new BoardDAO();
            int num = Integer.parseInt(request.getParameter("board_num"));
            int allCount = dbao.getAllCount();
            dbao.BoardDelete(num);
            dbao.Realignment(allCount);
            RequestDispatcher dis = request.getRequestDispatcher("FreeBoard.Pro");
            dis.forward(request, response);
            
        } else if(command.equals("/BoardModify.Pro")) {
            int num = Integer.parseInt(request.getParameter("board_num"));
            BoardDAO dbao = new BoardDAO();
            ArrayList<BoardBean> bean = new ArrayList<>();
            bean = dbao.getOneBoardInfo(num);
            request.setAttribute("bean", bean);
            RequestDispatcher dis = request.getRequestDispatcher("ModifyBoard.jsp");
            dis.forward(request, response);
            
        } else if(command.equals("/finishBoardModify.Pro")) {
            int num = Integer.parseInt(request.getParameter("board_num"));
            int readcount = Integer.parseInt(request.getParameter("readcount"));
            BoardDAO dbao = new BoardDAO();
            BoardBean bean = new BoardBean();
            bean.setBoard_num(num);
            bean.setBoard_name(request.getParameter("board_name"));
            bean.setBoard_subject(request.getParameter("board_subject"));
            bean.setBoard_content(request.getParameter("board_content"));
            bean.setReadcount(readcount);
            bean.setBoard_date(request.getParameter("board_date"));
            bean.setBoard_id(request.getParameter("board_id"));
            dbao.finishBoard(bean);
            ArrayList<BoardBean> bbean = new ArrayList<>();
            bbean = dbao.getOneBoardInfo(num);
            request.setAttribute("bean", bbean);
            RequestDispatcher dis = request.getRequestDispatcher("ReadBoardPage.jsp");
            dis.forward(request, response);
            
        }    else if(command.equals("/BoardComments.Pro")) {
            BoardDAO dbao = new BoardDAO();
            CommentBean incbean = new CommentBean();
            ArrayList<BoardBean> bean = new ArrayList<>();
            ArrayList<CommentBean> cbean = new ArrayList<>();
            int num = Integer.parseInt(request.getParameter("comment_grub"));
            incbean.setComment_id(request.getParameter("comment_id"));
            incbean.setComment_content(request.getParameter("comment_content"));
            incbean.setComment_grub(num);
            dbao.commentinsert(incbean);
            bean = dbao.getOneBoardInfo(num);
            cbean = dbao.getOneComment(num);
            request.setAttribute("bean", bean);
            request.setAttribute("cbean", cbean);
            RequestDispatcher dis = request.getRequestDispatcher("ReadBoardPage.jsp");
            dis.forward(request, response);
            
        }    else if(command.equals("/deleteComment.Pro")) {
            int num = Integer.parseInt(request.getParameter("board_num"));
            int comment_lev = Integer.parseInt(request.getParameter("comment_lev"));
            BoardDAO dbao = new BoardDAO();
            ArrayList<CommentBean> cbean = new ArrayList<>();
            ArrayList<BoardBean> bean = new ArrayList<>();
            dbao.deleteComment(num, comment_lev);
            cbean = dbao.getOneComment(num);
            bean = dbao.getOneBoardInfo(num);
            request.setAttribute("bean", bean);
            request.setAttribute("cbean", cbean);
            RequestDispatcher dis = request.getRequestDispatcher("ReadBoardPage.jsp");
            dis.forward(request, response);
            
        }
    }
}

BoardDAO.java

package Model;
 
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
 
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
 
 
 
public class BoardDAO {
    pageInfo pginfo = new pageInfo();
    private Connection con;
    private PreparedStatement pstmt;
    private ResultSet rs;
    
    //데이터베이스 연결 메소드
    public void getCon() {
        try {
            Context initCtx = new InitialContext();
            Context envCtx = (Context) initCtx.lookup("java:comp/env");
            DataSource ds = (DataSource) envCtx.lookup("jdbc/Pot");
            con = ds.getConnection();
            System.out.println("연결");
        } catch (Exception e) {
            System.out.println("실패");
            e.printStackTrace();
        }
    }
    //전체 게시물 갯수
    public int getAllCount() {
 
        int listCount = 0;
        getCon();
        try {
            String sql = "select count(*) from board";
            pstmt = con.prepareStatement(sql);
            rs = pstmt.executeQuery();
            if(rs.next()) {
                listCount = rs.getInt(1);
            }
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        } return listCount;
    }    
    //글 등록 메소드
    public void BoardInsert(BoardBean bean) {
        getCon();
        try {
            String sql = "insert into board values(null,?,?,?,?,now(),?)";
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, bean.getBoard_name());
            pstmt.setString(2, bean.getBoard_subject());
            pstmt.setString(3, bean.getBoard_content());
            pstmt.setInt(4, bean.getReadcount());
            pstmt.setString(5, bean.getBoard_id());
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //글 삭제 메소드
    public void BoardDelete(int num) {
        getCon();
        try {
            String sql = "delete from board where board_num=" + num;
            String sql2 = "delete from comment where comment_grub=" + num;
            pstmt = con.prepareStatement(sql);
            pstmt.executeUpdate();
            pstmt = con.prepareStatement(sql2);
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //정렬 메소드
    public void Realignment(int allCount) {
        getCon();
        try {
            String sql = "set @cnt=0 ";
            String sql2= "update board set board_num=@cnt:=@cnt+1 ";
            String sql3 = "alter table board auto_increment="+allCount;
            pstmt = con.prepareStatement(sql);
            pstmt.executeQuery();
            pstmt = con.prepareStatement(sql2);
            pstmt.executeUpdate();
            pstmt = con.prepareStatement(sql3);
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //글 수정 메소드
    public void finishBoard( BoardBean bean) {
        getCon();
        try {
            String sql = "update board set board_subject=?, board_content=? where board_num=?";
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, bean.getBoard_subject());
            pstmt.setString(2, bean.getBoard_content());
            pstmt.setInt(3, bean.getBoard_num());
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //글 내용보기 메소드드
    public ArrayList<BoardBean> getOneBoardInfo(int num) {
        ArrayList<BoardBean> bean = new ArrayList<>();
        getCon();
        try {
            String sql = "select * from board where board_num=" + num;
            pstmt = con.prepareStatement(sql);
            rs = pstmt.executeQuery();
            while(rs.next()) {
                BoardBean bbean = new BoardBean();
                bbean.setBoard_num(rs.getInt("board_num"));
                bbean.setBoard_name(rs.getString("board_name"));
                bbean.setBoard_subject(rs.getString("board_subject"));
                bbean.setBoard_content(rs.getString("board_content"));
                bbean.setReadcount(rs.getInt("board_readcount"));
                bbean.setBoard_date(rs.getString("board_date"));
                bbean.setBoard_id(rs.getString("board_id"));
                bean.add(bbean);
            }
            con.close();
        } catch (Exception e) {
            // TODO: handle exception
            e.printStackTrace();
        } return bean;
    }
    //글 조회수 메소드
    public void readCountup(int num) {
        getCon();
        try {
            String sql = "update board set board_readcount = board_readcount + 1 where board_num=" + num;
            pstmt = con.prepareStatement(sql);
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //글 전체 리턴 메소드
    public ArrayList<BoardBean> getAllList(int StartRow){
        ArrayList<BoardBean> bbean = new ArrayList<>();
        getCon();
        try {
            String sql = "select * from board order by board_num desc limit ?,10";
            pstmt = con.prepareStatement(sql);
            pstmt.setInt(1, StartRow);
            rs = pstmt.executeQuery();
            while(rs.next()) {
                BoardBean bean = new BoardBean();
                bean.setBoard_num(rs.getInt("board_num"));
                bean.setBoard_name(rs.getString("board_name"));
                bean.setBoard_subject(rs.getString("board_subject"));
                bean.setBoard_content(rs.getString("board_content"));
                bean.setBoard_date(rs.getString("board_date"));
                bean.setReadcount(rs.getInt("board_readcount"));
                bbean.add(bean);
            }
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        } return bbean;
    }
    //댓글 등록 메소드
    public void commentinsert(CommentBean incbean) {
        getCon();
        int commentcount= 0;
        try {
            String max_sql = "select count(comment_lev) from comment where comment_grub=?";
            pstmt = con.prepareStatement(max_sql);
            pstmt.setInt(1, incbean.getComment_grub());
            rs = pstmt.executeQuery();
            if(rs.next()) {
                commentcount = rs.getInt(1) +1;
                System.out.println(incbean.getComment_grub());
            } else {
                commentcount = 1;
                System.out.println(incbean.getComment_grub());
            }
            String sql = "insert into comment values(?,?,?,?,now())";
            pstmt = con.prepareStatement(sql);
            pstmt.setString(1, incbean.getComment_id());
            pstmt.setString(2, incbean.getComment_content());
            pstmt.setInt(3, incbean.getComment_grub());
            pstmt.setInt(4, commentcount);
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        } 
    }
    //한 게시물의 댓글 가져오는 메소드
    public ArrayList<CommentBean> getOneComment(int num){
        ArrayList<CommentBean> cbean = new ArrayList<>();
        getCon();
        try {
            String sql = "select * from comment where comment_grub = " + num;
            pstmt = con.prepareStatement(sql);
            rs = pstmt.executeQuery();
            while(rs.next()) {
                CommentBean bean = new CommentBean();
                bean.setComment_id(rs.getString("comment_id"));
                bean.setComment_content(rs.getString("comment_content"));
                bean.setComment_grub(rs.getInt("comment_grub"));
                bean.setComment_lev(rs.getInt("comment_lev"));
                bean.setComment_date(rs.getString("comment_date"));
                cbean.add(bean);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } return cbean;
    }
 
    //답변 삭제 메소드
    public void deleteComment(int num, int comment_lev) {
        getCon();
        try {
            String sql = "delete from comment where comment_grub=? and comment_lev=?";
            pstmt = con.prepareStatement(sql);
            pstmt.setInt(1, num);
            pstmt.setInt(2, comment_lev);
            pstmt.executeUpdate();
            con.close();
        } catch (Exception e) {
            e.printStackTrace();
        }    
    }
}

auto_increment의 단점은 위에서 설명했지만, 중간 번호를 삭제시 재정렬이 자동으로 이루지지않음. 그래서 삭제시 재정렬 메소드인 Realignment()호출하여 count를 0으로 주고 다시 차례로 입력되게 만들었음. 하지만 게시글이 많아지면 안쓰는걸 추천. 그래서 댓글은 1씩 증가하게 만들었음.

글쓰기 기능과 페이징넘버링도 잘 되었습니다.

조회수도 정상으로 잘 들어왔어요

3번글을 수정하였다가 삭제를 하면 auto_increment를 재정렬하여 정상적으로 숫자가 들어갔습니다.

아직 부족한것도 많고 어설픈것도 많은 java/jsp 게시판 이해가 안되거나  더 좋은 방법이 있으시면 댓글좀 남겨주세요.