Languages/java

[JAVA] 페이징 처리

뱅타 2021. 4. 6. 20:01

페이징 시 알아두면 좋을 용어

페이징처리

연산식 구하기

총 페이지 수 연산(totalPage):

  • totalRecord % screenSize== 0? totalRecord/ screenSize: totalRecord/ screenSize + 1

시작게시물번호 연산(startRow):

  • startRow = (currentPage -1) * screenSize + 1;
  • endRow = currentPage * screenSize;

시작페이지 연산(startPage):

  • endPage = (currentPage + (blockSize - 1)) / blockSize * blockSize;
  • startPage = endPage - (blockSize -1);

필요 요소

  • totalPage는 totalRecord의 값을 알아야 구할 수 있다.
  • startRow, startPage 두개 모두 currentPage를 알아야 구할 수 있다.

VO에서 값을 가져간다 → db에 해당 쿼리문 실행 → 값을 다시 vo로

  • 코드(PagingVO)
    package kr.or.ddit.vo;

import static org.junit.Assume.assumeNoException;

import java.io.Serializable;
import java.util.List;
import java.util.Set;

import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

@Setter
@Getter
@NoArgsConstructor // 기본생성자
public class PagingVO<T> implements Serializable{
	
	public PagingVO(int screenSize, int blockSize) {
		super();
		this.screenSize = screenSize;
		this.blockSize = blockSize;
	}

	private int totalRecord;
	private int screenSize = 10;
	private int blockSize = 5;
	private int currentPage;
	
	private int totalPage;
	private int startRow;
	private int endRow;
	private int startPage;
	private int endPage;
	private List<T> dataList;
	
	private SearchVO simpleSearch;

	public void setTotalRecord(int totalRecord) {
		this.totalRecord = totalRecord;
		totalPage = totalRecord % screenSize == 0?
				totalRecord/screenSize :
				totalRecord/screenSize +1;
	}
	
	public void setCurrentPage(int currentPage) {
		this.currentPage = currentPage;
		startRow = (currentPage - 1)*screenSize + 1;
		endRow = currentPage * screenSize;
		endPage = (currentPage + (blockSize-1))/blockSize * blockSize;
		startPage = endPage - (blockSize  - 1);
	}
	
	private static String aPattern = "<a href='#' data-page = '%d'>[%s]</a>";
	private static String currentPagePtrn = "<a href='#'>[%s]</a>";
	
	public String getPagingHTML() {
		StringBuffer html = new StringBuffer();
		if(startPage > 1) {
			html.append(
				String.format(aPattern, (startPage-1), "이전")
			);
		}
		endPage = endPage < totalPage ? endPage : totalPage;
		for(int page=startPage; page<=endPage; page++) {
			if(page == currentPage) {
				html.append(
					String.format(currentPagePtrn, page+"")
				);
			}else {
				html.append(
					String.format(aPattern, page, page+"")
				);
			}
		}
		if(endPage < totalPage) {
			html.append(
				String.format(aPattern, (endPage +1), "다음")
			);
		}
		return html.toString();
	}
	
}
  • 코드(member.xml)
    <sql id="searchFrag">
		<where>
			<if test="simpleSearch!=null and @org.apache.commons.lang3.StringUtils@isNotBlank(simpleSearch.searchWord)">
				<choose>
					<when test="simpleSearch.searchType eq 'name'">
						INSTR(MEM_NAME, #{simpleSearch.searchWord}) > 0
					</when>
					<when test="simpleSearch.searchType eq 'address'">
						INSTR(MEM_ADD1, #{simpleSearch.searchWord}) > 0
					</when>
					<otherwise>
						INSTR(MEM_NAME, #{simpleSearch.searchWord}) > 0
						OR
						INSTR(MEM_ADD1, #{simpleSearch.searchWord}) > 0
					</otherwise>
				</choose>
			</if>
		</where>
	</sql>
	<select id="selectMemberList" resultType="memberVO" parameterType="PagingVO" >
		SELECT B.*
		FROM(
			SELECT A.*, ROWNUM RNUM
			FROM(
				SELECT ROWID RID, mem_id, mem_pass, mem_name, mem_mail 
				, MEM_ADD1
				FROM member
				<include refid="searchFrag" />
				ORDER BY RID DESC
			) A
		) B
		<![CDATA[
			WHERE RNUM >= #{startRow} AND RNUM <= #{endRow}
		]]>
	</select>
	
	<select id="selectTotalRecord" resultType = "int" parameterType ="PagingVO">
		SELECT COUNT(*)
		FROM MEMBER
		<include refid="searchFrag" />
	</select>
  • MemberDAOImpl.java
    package kr.or.ddit.member.dao;

import java.util.List;

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import kr.or.ddit.db.mybatis.CustomSqlSessionFactoryBuilder;
import kr.or.ddit.vo.MemberVO;
import kr.or.ddit.vo.PagingVO;

public class MemberDAOImpl implements IMemberDAO {
	// 싱글톤 만들기
	private static MemberDAOImpl self;
	private MemberDAOImpl() {}
	public static MemberDAOImpl getInstance() {
		if(self==null) self = new MemberDAOImpl();
		return self;
	}
	
	private SqlSessionFactory sessionFactory = 
			CustomSqlSessionFactoryBuilder.getSessionFactory();
	

	@Override
	public MemberVO selectMemberForAuth(String mem_id) {
		try( SqlSession session = sessionFactory.openSession();
		){
//			return (MemberVO) session.selectOne("kr.or.ddit.member.dao.IMemberDAO.selectMemberForAuth", mem_id);
			// mapper proxy - 가짜 매퍼
			IMemberDAO mapper = session.getMapper(IMemberDAO.class);
			return mapper.selectMemberForAuth(mem_id);
		}
	}

	@Override
	public MemberVO selectMemberDetail(String mem_id) {
		try(
			SqlSession session = sessionFactory.openSession();
		){
			IMemberDAO mapper = session.getMapper(IMemberDAO.class);
			return mapper.selectMemberDetail(mem_id);
		}
	}

	@Override
	public int insertMember(MemberVO member) {
		try(
			SqlSession session = sessionFactory.openSession();
		){
			IMemberDAO mapper = session.getMapper(IMemberDAO.class);
			int cnt = mapper.insertMember(member);
			session.commit();
			return cnt;
		}
	}

	@Override
	public int updateMember(MemberVO member) {
		try(
			SqlSession session = sessionFactory.openSession();
			// 문제가 있다. 문제가 있어도 commit을 해버림
		){
//			MemberDAOImpl.class.equals(this.getClass());
			IMemberDAO mapper = session.getMapper(IMemberDAO.class);
			int cnt = mapper.updateMember(member);
			session.commit();
			return cnt;
		}
	}

	@Override
	public int deleteMember(String mem_id) {
		try(
				SqlSession session = sessionFactory.openSession();	
			){
				IMemberDAO mapper =
						session.getMapper(IMemberDAO.class);
				int cnt = mapper.deleteMember(mem_id);
				session.commit();
				return cnt;
			}
	}

	@Override
	public List<MemberVO> selectMemberList(PagingVO pagingVO) {
		try(
				SqlSession session = sessionFactory.openSession();
				// 문제가 있다. 문제가 있어도 commit을 해버림
			){
//				MemberDAOImpl.class.equals(this.getClass());
				IMemberDAO mapper = session.getMapper(IMemberDAO.class);
				return mapper.selectMemberList(pagingVO);
			}
	}
	@Override
	public int selectTotalRecord(PagingVO pagingVO) {
		try(
				SqlSession session = sessionFactory.openSession();
				// 문제가 있다. 문제가 있어도 commit을 해버림
			){
//				MemberDAOImpl.class.equals(this.getClass());
				IMemberDAO mapper = session.getMapper(IMemberDAO.class);
				return mapper.selectTotalRecord(pagingVO);
			}
	}

}
  • MemberServiceImpl.java
    package kr.or.ddit.member.service;

import java.lang.reflect.InvocationTargetException;
import java.util.List;

import org.apache.commons.beanutils.BeanUtils;

import kr.or.ddit.enumpkg.ServiceResult;
import kr.or.ddit.member.UserNotFoundException;
import kr.or.ddit.member.dao.IMemberDAO;
import kr.or.ddit.member.dao.MemberDAOImpl;
import kr.or.ddit.vo.MemberVO;
import kr.or.ddit.vo.PagingVO;

public class MemberServiceImpl implements IMemberService {
	private IMemberDAO dao = MemberDAOImpl.getInstance();
	private IAuthenticateService authService = new AuthenticateServiceImpl();

	@Override
	public MemberVO retrieveMember(String mem_id) {
		MemberVO savedMember = dao.selectMemberDetail(mem_id);
		if (savedMember == null) {
			// custom exception 발생
			// compile error가 발생하면 checked exception이다. ex)Exceiption()
			throw new UserNotFoundException("아이디에 해당하는 회원이 존재하지 않음.");
		}
		return savedMember;
		// 특정 상황에 쓸 수 있는 커스텀 익셉션
	}

	@Override
	public ServiceResult createMember(MemberVO member) {
		ServiceResult result = null;
		if (dao.selectMemberDetail(member.getMem_id()) == null) { // 중복되지 않는다면
			int rowcnt = dao.insertMember(member);
			if (rowcnt > 0) { // 성공
				result = ServiceResult.OK;
			} else { // 실패
				result = ServiceResult.FAIL;
			}
		} else { // 중복
			result = ServiceResult.PKDUPLICATED;
		}
		return result;
	}

	@Override
	public ServiceResult modifyMember(MemberVO member) {
		retrieveMember(member.getMem_id());

		ServiceResult result = authService.authenticate(new MemberVO(member.getMem_id(), member.getMem_pass()));

		if (ServiceResult.OK.equals(result)) {
			int rowcnt = dao.updateMember(member);
			if (rowcnt > 0) {
				result = ServiceResult.OK;
			} else {
				result = ServiceResult.FAIL;
			}
		}
		return result;
	}

	@Override
	public ServiceResult removeMember(MemberVO member) {
		retrieveMember(member.getMem_id());

		ServiceResult result = authService.authenticate(new MemberVO(member.getMem_id(), member.getMem_pass()));
		if (ServiceResult.OK.equals(result)) {
			int rowcnt = dao.deleteMember(member.getMem_id());
			if (rowcnt > 0) {
				result = ServiceResult.OK;
			} else {
				result = ServiceResult.FAIL;
			}
		}
		return result;
	}

	@Override
	public List<MemberVO> retrieveMemberList(PagingVO pagingVO) {
		return dao.selectMemberList(pagingVO);
	}

	@Override
	public int retrieveMemberCount(PagingVO<MemberVO> pagingVO) {
		return dao.selectTotalRecord(pagingVO);
	}
}
  • MemberListServlet.java
    package kr.or.ddit.member.controller;

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 javax.servlet.http.HttpSession;

import kr.or.ddit.member.service.IMemberService;
import kr.or.ddit.member.service.MemberServiceImpl;
import kr.or.ddit.vo.MemberVO;
import kr.or.ddit.vo.PagingVO;
import kr.or.ddit.vo.SearchVO;

@WebServlet("/member/memberList.do")
public class MemberListServlet extends HttpServlet {
	IMemberService service = new MemberServiceImpl();
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setCharacterEncoding("utf-8");
		String searchType = req.getParameter("searchType");
		String searchWord = req.getParameter("searchWord");
		
		SearchVO searchVO = new SearchVO(searchType, searchWord);
		
		
		String pageParam = req.getParameter("page");
		int currentPage = 1;
		if(pageParam!=null && pageParam.matches("\\d+")) {
			currentPage = Integer.parseInt(pageParam);
		}
		PagingVO<MemberVO> pagingVO = new PagingVO(7, 2);
		pagingVO.setCurrentPage(currentPage);
		// 검색 조건 먼저 담아주어야함.
		pagingVO.setSimpleSearch(searchVO);
		
		int totalRecord = service.retrieveMemberCount(pagingVO);
		pagingVO.setTotalRecord(totalRecord);
		
		List<MemberVO> memberList =  service.retrieveMemberList(pagingVO);
		pagingVO.setDataList(memberList);
		
		req.setAttribute("pagingVO", pagingVO);
		
		String view = "/WEB-INF/views/member/memberList.jsp";
		req.getRequestDispatcher(view).forward(req, resp);
	}
}
  • memberList.jsp
    <%@page import="kr.or.ddit.vo.SearchVO"%>
<%@page import="kr.or.ddit.vo.PagingVO"%>
<%@page import="kr.or.ddit.vo.MemberVO"%>
<%@page import="java.util.List"%>
<%@ 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>
<jsp:include page = "/includee/preScript.jsp" />
</head>
<body>
<h4>회원 목록 조회</h4>

<table border= '1'>
	<thead>
		<tr>
			<th>No.</th>
			<th>회원아이디</th>
			<th>회원명</th>
			<th>이메일</th>
			<th>휴대폰</th>
			<th>마일리지</th>
			<th>탈퇴여부</th>
			<th>지역</th>
		</tr>
	</thead>
	<tbody>
	<%
		PagingVO<MemberVO> pagingVO = (PagingVO) request.getAttribute("pagingVO");
		List<MemberVO> memberList = pagingVO.getDataList();
		if(memberList.size()>0){
			for(MemberVO member : memberList){
				%>
				<tr>
					<td><%=member.getRnum() %></td>
					<td><%=member.getMem_id() %></td>
					<td><%=member.getMem_name() %></td>
					<td><%=member.getMem_mail() %></td>
					<td><%=member.getMem_hp() %></td>
					<td><%=member.getMem_mileage()%></td>
					<td>
						<%="Y".equals(member.getMem_delete())?"탈퇴" : "" %>
					</td>
					<td><%=member.getMem_add1()%></td>
				</tr>
				<%
			}
		}else{
			%>
			<tr>
				<td colspan="5">
					등록된 데이터 없음.
			<%
		}
			%>
	</tbody>
	<tfoot>
		<tr>
			<td colspan="6">
					<form id = "searchForm">
					
						<input type = "text" name = "searchType" value="${pagingVO.simpleSearch.searchType }"/>
						<input type = "text" name = "searchWord" value="${pagingVO.simpleSearch.searchWord }"/>
						<input type = "text" name = "page" />
					</form>
					<div id = "searchUI">
						<select name = "searchType">
							<option value>전체</option>
							<option value="name">이름</option>
							<option value="address">지역</option>
						</select>
						<input type = "text" name = "searchWord" value="${pagingVO.simpleSearch.searchWord }" />
						<input id = "searchBtn" type = "button" value = "검색" />
					</div>
				<div id = "pagingArea">
					<%=pagingVO.getPagingHTML() %>
				</div>
			</td>
		</tr>
	</tfoot>
</table>
<script type = "text/javascript">
	let searchForm = $("#searchForm");
	let searchUI = $("#searchUI");
	searchUI.find("[name='searchType']").val("${pagingVO.simpleSearch.searchType }");
	$("#searchBtn").on("click", function(){
		let inputs = searchUI.find(":input[name]");
		$(inputs).each(function(idx, input){
			let name = $(this).attr("name");
			let sameInput = searchForm.find("[name='"+name+"']")
			$(sameInput).val($(this).val());
		});
		searchForm.submit();
	});
	
	$("#pagingArea").on("click", "a", function(event){
		event.preventDefault();
		let page = $(this).data("page");
		if(page){
			searchForm.find("[name='page']").val(page);
			searchForm.submit();
		}
		return false;
	});
</script>

</body>
</html>

*알면 좋은 단축키들 - alt +shift+c

  • 해당 인스턴스 파라미터 변경하기. preview로 무엇이 영향을 받는지 알 수 있다.

HAS A 관계에서는 꼭 result Map을 꼭 쓰지 않아도 된다.

  • has a → association
  • has many → collections

strict alias를 잘 쓰면 된다.

**추가

.find(":input[name]") 분석

: 모든 input 태그

[name] name을 가지고 있는 모든 input 태그.

data-page로 값 찾기.

ogln과 el의 문법은 거의 비슷하다.

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