javaweb分页功能

==SQL语句==

select * from table order by id desc limit (curPage-1)*pageSize,pageSize

curPage : 当前页

pageSize : 每页显示的条数

==Dao层设计==

public List<Goods> getGoodsPaging(int curPage,int pageSize){
		String sql = "select * from goods order by gid desc limit ?,?";
		Connection conn = null;
		PreparedStatement ps = null;
		ResultSet rs = null;
		List<Goods> gList = new ArrayList<Goods>();
		try {
			conn = db.getConnection();
			ps = conn.prepareStatement(sql);
			ps.setInt(1, (curPage-1)*pageSize);
			ps.setInt(2, pageSize);
			log.info(ps.toString());
			rs = ps.executeQuery();
			while(rs.next()){
				Goods goods = new Goods();
				goods.setGid(rs.getInt("gid"));
				goods.setGname(rs.getString("gname"));
				goods.setGpicName(rs.getString("gpicName"));
				goods.setGprice(rs.getFloat("gprice"));
				gList.add(goods);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			db.release(rs, ps, conn);
		}
		return gList;
	}

返回从数据库查到的list集合,并且还要得到数据库总条数,用于求得总共多少页(没copy上来)

==业务层设计==

++得到总页数++

public int getTotalPage(){
        // getTotal() 为数据总条数
		return this.getTotal() % this.offset ==0 ?
		    this.getTotal() / this.offset:this.getTotal() / this.offset+1;
	}

每一页得到的数据

// 按照分页得到数据
public List<Goods> getGoodsPaging(int curPage,int limit){
		return goodsDao.getGoodsPaging(curPage,limit); //调用Dao层方法
	}

Servlet

protected void doGet(HttpServletRequest req, HttpServletResponse resp)
			throws ServletException, IOException {
		ServletContext application = this.getServletContext();
		
		//调用getParameter方法通过url传参方式得到当前页值
		String pageIndex = (String) req.getParameter("curPage");
		int curPage = pageIndex == null?1:Integer.valueOf(pageIndex); // 如果为空，当前页则赋值1
		PageUtils pu = new PageUtils(curPage); //实例化分页工具类并传入当前页

		req.setAttribute("curPage", curPage); // 当前页
		req.setAttribute("totalPage", pu.getTotalPage()); // 总页数
		req.setAttribute("goodsList",pu.getDataByPage()); // 每页的数据

		req.getRequestDispatcher("/WEB-INF/index_show.jsp").forward(req, resp);
	}

==View层设计==

循环展示当前页的数据

<tbody>
	<c:if test="${requestScope.curPage != null }">
		<c:set var="curPage" value="${requestScope.curPage }"></c:set>
		<c:set var="totalPage" value="${requestScope.totalPage }"></c:set>
	</c:if>
	<c:forEach items="${requestScope.goodsList }" var="g">
		<tr>
			<td><img class=" img-responsive"
				src="image/${g.gpicName}.jpg" style="height: 40px;width: 70px;" />
			</td>
			<td>${g.gname }</td>
			<td><font color="red">¥${g.gprice }</font></td>
			<td><a href="okCart/addCart?gid=${g.gid }">添加到购物车</a></td>
		</tr>
	</c:forEach>
</tbody>

显示分页条

<c:if test="${requestScope.curPage != null }">
	<c:set var="curPage" value="${requestScope.curPage }"></c:set>
	<c:set var="totalPage" value="${requestScope.totalPage }"></c:set>
	<nav aria-label="Page navigation">
		<ul class="pagination">
			<li><a href="/okCart/"> 首页</a></li>
			<c:forEach begin="1" end="${totalPage }" var="i">
				<c:if test="${curPage==i}">
			        <li class="active"><span>${i }</span></li>
				</c:if>
				<c:if test="${curPage!=i}">
			    	<li><a href="/okCart/index?curPage=${i }">${i }</a></li>
				</c:if>
			</c:forEach>
			<li><a href="/okCart/index?curPage=${totalPage }">尾页</a></li>
		</ul>
	</nav>
</c:if>

---

最终显示效果图

附上PageUtils.class

/**
 * @类功能说明：    分页工具类
 * @作者：汪思源
 * @创建时间：2018-7-13 下午3:16:34
 * @版本：V1.0
 */
public class PageUtils {
	private GoodsService goodsSer;
	private int curPage;//当前页
	private int offset = 5;//每页显示条数
	public PageUtils(int curPage){
		this.goodsSer = new GoodsService();
		this.curPage = curPage;
	}

	/**
	 * 得到总数据条数
	 * @参数： @return
	 * @return int
	 * @throws
	 */
	public int getTotal(){
		return goodsSer.getGoodsTotal();
	}

	/**
	 * 得到总页数
	 * @参数： @return
	 * @return int
	 * @throws
	 */
	public int getTotalPage(){
		return this.getTotal() % this.offset ==0 ?this.getTotal() / this.offset:this.getTotal() / this.offset+1;
	}

	/**
	 * 通过分页得到数据
	 * @参数： @return
	 * @return List<Goods>
	 * @throws
	 */
	public List<Goods> getDataByPage(){
		return goodsSer.getGoodsPaging(curPage, offset);
	}
}