Press release System < pagination >

Paging implementation:

The following key steps are required to achieve paginated display of data:

① determine the total number of pages displayed per page

② calculate the total number of pages displayed

③ Writing SQL statements

Implementation results:

When you click on the next page, the Address bar address is? pageindex=2

1. Create Util package, page class, define related attributes and encapsulate:

 PackageCn.news.util;Importjava.util.List;ImportCn.news.entity.NewsDetail; Public classPage {//Current Page    Private intPageIndex; //Page Record Count    Private intpageSize; //Dramatic show real Data    PrivateList<newsdetail>list; //Total Pages    Private intTotalPages; //Total Record Count    Private inttotalrecords;  Public intGetpageindex () {returnPageIndex; }     Public voidSetpageindex (intPageIndex) {         This. PageIndex =PageIndex; }     Public intgetpagesize () {returnpageSize; }     Public voidSetPageSize (intpageSize) {         This. pageSize =pageSize; }     PublicList<newsdetail>getList () {returnlist; }     Public voidSetlist (list<newsdetail>list) {         This. List =list; }     Public intgettotalpages () {returnTotalPages; }     Public voidSettotalpages (inttotalpages) {         This. TotalPages =TotalPages; }     Public intgettotalrecords () {returntotalrecords; }     Public voidSettotalrecords (inttotalrecords) {         This. totalrecords =totalrecords; }}

2, in the DAO implementation class Newsdetaildaoimpl definition obtains the news current page data method Getonepage, and implants two parameters pageindex, pageSize

@Override PublicList<newsdetail> Getonepage (intPageIndex,intpageSize)throwsException {List<NewsDetail> list=NewArraylist<newsdetail>(); String SQL= "SELECT Top" +pagesize+ "* from Newsdetails where newsId not in (select Top" + (pageIndex-1) *pagesize+ "NewsId from Newsdet ails) "; ResultSet RS=executeQuery (SQL); if(rs!=NULL)            {                 while(Rs.next ()) {Newsdetail News=NewNewsdetail (); 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); }            }            returnlist; }

3, in the Newsservlet class to pass data to the JSP page

 PackageCn.news.servlet;Importjava.io.IOException;Importjava.util.List;Importjavax.servlet.ServletException;ImportJavax.servlet.http.HttpServlet;Importjavax.servlet.http.HttpServletRequest;ImportJavax.servlet.http.HttpServletResponse;ImportCn.news.entity.NewsDetail;ImportCn.news.impl.NewsDetailDaoImpl;ImportCn.news.util.Page; Public classNewsservletextendsHttpServlet {/**     */     Public voiddoget (httpservletrequest request, httpservletresponse response)throwsservletexception, IOException {doPost (request,response); }    /**         */     Public voidDoPost (httpservletrequest request, httpservletresponse response)throwsservletexception, IOException {//Instantiate DAONewsdetaildaoimpl dao=NewNewsdetaildaoimpl (); Try{Page page=NewPage (); //Default 3 Data            intPagesize=3;            Page.setpagesize (pageSize); //Current Page            intMyindex=1; String PageIndex=request.getparameter ("PageIndex"); if(pageindex!=NULL&& ("!pageindex.equals")) {Myindex=Integer.parseint (PageIndex); }Else{Myindex=1; }                //Current Page AssignmentPage.setpageindex (Myindex); intMytotalpages=0; inttotalpages=Dao.getallcount (); if(totalpages%pagesize==0) {mytotalpages=totalpages/pageSize; }                Else{mytotalpages=totalpages/pagesize+1;                                } page.settotalpages (Mytotalpages); //Generic DataList<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. Get the generic collection on index.jsp page and get the current page and next page

    <%        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" > Current page: [<%=page2.getpageindex ()%>/<%=page2.gettotalpages ()%>]& nbsp <a href= "<%=path%>/servlet/newsservlet?pageindex=<%=page2.getpageindex () +1%>" > Next </a> <a href= "#" > End </a> </p>      </ul>

Press release System < pagination >