青岛城乡建筑设计院有限公司/济南seo优化外包服务公司

分页实现：

实现数据的分页显示，需要以下几个关键步骤：

①确定每页显示的总页数

②计算显示的总页数

③编写SQL语句

实现效果如图所示：

 

 

当点击下一页时，地址栏地址为?pageIndex=2

1、创建util包，Page类，定义相关属性并进行封装：

package cn.news.util;import java.util.List;import cn.news.entity.NewsDetail;public class Page {//当前页private int pageIndex;//页面记录数private int pageSize;//本业显示真实数据private List<NewsDetail> list;//总页数private int totalPages;//总记录数private int totalRecords;public int getPageIndex() {return pageIndex;}public void setPageIndex(int pageIndex) {this.pageIndex = pageIndex;}public int getPageSize() {return pageSize;}public void setPageSize(int pageSize) {this.pageSize = pageSize;}public List<NewsDetail> getList() {return list;}public void setList(List<NewsDetail> list) {this.list = list;}public int getTotalPages() {return totalPages;}public void setTotalPages(int totalPages) {this.totalPages = totalPages;}public int getTotalRecords() {return totalRecords;}public void setTotalRecords(int totalRecords) {this.totalRecords = totalRecords;}
}

 

 

2、在Dao实现类NewsDetailDaoImpl定义获取新闻当前页的数据的方法getonePage，并植入两个参数pageIndex, pageSize

    @Overridepublic List<NewsDetail> getonePage(int pageIndex, int pageSize)throws Exception {List<NewsDetail> list=new ArrayList<NewsDetail>();String sql="select top "+pageSize+" * from newsDetails where newsId not in(select top "+(pageIndex-1)*pageSize+" newsId from newsDetails)";ResultSet rs=executeQuery(sql);if(rs!=null){while(rs.next()){NewsDetail news=new NewsDetail();news.setNewsId(rs.getInt("newsId"));news.setNewsTitle(rs.getString("newsTitle"));news.setNewsContent(rs.getString("newsContent"));news.setNewsCreateDate(rs.getDate("newsCreateDate"));news.setNewsAuthor(rs.getString("newsAuthor"));news.setNewsCategoryId(rs.getInt("newsCategoryId"));list.add(news);}}return list;}

3、在NewsServlet类中把数据传递给Jsp页面

package cn.news.servlet;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import cn.news.entity.NewsDetail;
import cn.news.impl.NewsDetailDaoImpl;
import cn.news.util.Page;public class NewsServlet extends HttpServlet {/***/public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request,response);}/***/public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//实例化daoNewsDetailDaoImpl dao=new NewsDetailDaoImpl();try {Page page=new Page();//默认3条数据int pageSize=3;page.setPageSize(pageSize);//当前页int myindex=1;String pageIndex=request.getParameter("pageIndex");if(pageIndex!=null&&(!pageIndex.equals(""))){myindex=Integer.parseInt(pageIndex);}else {myindex=1;}//当前页赋值
                page.setPageIndex(myindex);int mytotalPages=0;int totalPages=dao.getAllCount();if(totalPages%pageSize==0){mytotalPages=totalPages/pageSize;}else{mytotalPages=totalPages/pageSize+1;}page.setTotalPages(mytotalPages);//泛型数据List<NewsDetail> list= dao.getonePage(page.getPageIndex(), pageSize);page.setList(list);request.setAttribute("list", page);request.getRequestDispatcher("/index.jsp").forward(request, response);//List<NewsDetail> list=dao.getAllNews();
            } catch (Exception e) {e.printStackTrace();}}}

4、在index.jsp页面得到泛型集合，并获取当前页数和下一页

    <%Page page2=(Page)request.getAttribute("list");for(NewsDetail item:page2.getList()){%><li><a href='newspages/news_read.jsp'><%=item.getNewsTitle() %></a><span><%=item.getNewsCreateDate() %></span></li><%}%><p align="right"> 当前页数:[<%=page2.getPageIndex() %>/<%=page2.getTotalPages() %>]&nbsp; <a href="<%=path %>/servlet/NewsServlet?pageIndex=<%=page2.getPageIndex()+1%>">下一页</a> <a href="#">末页</a> </p></ul>