페이징 게시판

-- MySQL 에서 100 건 INSERT
INSERT INTO myboard(title, writer, content)
SELECT CONCAT('테스트 글 ', seq), 'tester', '본문'
FROM (
    SELECT @row := @row + 1 AS seq
    FROM (SELECT 0 UNION SELECT 1 UNION SELECT 2) t1,
         (SELECT 0 UNION SELECT 1 UNION SELECT 2) t2,
         (SELECT 0 UNION SELECT 1 UNION SELECT 2 UNION SELECT 3) t3,
         (SELECT @row := 0) r
) numbers
LIMIT 100;

v6 의 /board/list 에 들어가 100 건이 한 화면에 쏟아지는 것을 직접 본다.

// com/smhrd/domain/Paging.java — 도메인 아님 (계산용)
public class Paging {
    private int pageNo, pageSize, totalCount;
    public Paging(int pageNo, int pageSize, int totalCount) {
        this.pageNo = pageNo < 1 ? 1 : pageNo;
        this.pageSize = pageSize;
        this.totalCount = totalCount;
    }
    public int getStartRow()    { return (pageNo - 1) * pageSize; }
    public int getTotalPages()  { return (int) Math.ceil((double) totalCount / pageSize); }
    public int getPageNo()      { return pageNo; }
    public int getPageSize()    { return pageSize; }
}

<!-- BoardMapper.xml — 스키마 변경 없음, SQL 만 추가 -->
<select id="selectListPaging" parameterType="map"
        resultType="com.smhrd.domain.Board">
  SELECT num, title, writer, content, created_at
  FROM myboard
  ORDER BY num DESC
  LIMIT #{startRow}, #{pageSize}
</select>

<select id="count" resultType="int">
  SELECT COUNT(*) FROM myboard
</select>

// BoardService
public Paging buildPaging(int pageNo) {
    return new Paging(pageNo, 10, mapper.count());
}
public List<Board> selectListPaging(Paging paging) {
    Map<String, Integer> param = new HashMap<>();
    param.put("startRow", paging.getStartRow());
    param.put("pageSize", paging.getPageSize());
    return mapper.selectListPaging(param);
}

@GetMapping("/board/list")
public String list(@RequestParam(defaultValue = "1") int page,
                    Model model) {
    Paging paging = service.buildPaging(page);
    model.addAttribute("boards", service.selectListPaging(paging));
    model.addAttribute("paging", paging);
    return "board/list";
}

<!-- list.jsp -->
<c:forEach var="b" items="${boards}">
    <tr><td>${b.num}</td><td>${b.title}</td><td>${b.writer}</td></tr>
</c:forEach>

<c:forEach begin="1" end="${paging.totalPages}" var="p">
    <c:choose>
        <c:when test="${p == paging.pageNo}"><strong>${p}</strong></c:when>
        <c:otherwise><a href="?page=${p}">${p}</a></c:otherwise>
    </c:choose>
</c:forEach>