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
@Override
public 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dao
NewsDetailDaoImpl 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() %>] <a href="<%=path %>/servlet/NewsServlet?pageIndex=<%=page2.getPageIndex()+1%>">下一页</a> <a href="#">末页</a> </p>
</ul>