// 刷新當(dāng)前頁面信息
public void refresh() {
if (totalPages <= 1) {
hasPrevious = false;
hasNext = false;
} else if (currentPage == 1) {
hasPrevious = false;
hasNext = true;
} else if (currentPage == totalPages) {
hasPrevious = true;
hasNext = false;
} else {
hasPrevious = true;
hasNext = true;
}
}
}
Action一：
public ActionForward queryWithPage(ActionMapping actionMapping,
ActionForm actionForm,
HttpServletRequest httpServletRequest,
HttpServletResponse httpServletresponse) {
Collection clInfos = null;//用于輸出到頁面的記錄集合
int totalRows;//記錄總行數(shù)
VehiclePropertyDAO vehicleDAO = new VehiclePropertyDAO();
//取得當(dāng)前表中的總行數(shù)
try {
totalRows = vehicleDAO.getRows("select count(*) from VehicleProperty");
} catch (Exception ex) {
servlet.log(ex.toString());
return actionMapping.findForward(Constants.FAILURE);
}
//通過PagerHelper類來獲取用于輸出到頁面的pager對象
Pager pager=PagerHelper.getPager(httpServletRequest,totalRows);
//取出從startRow開始的pageSize行記錄
try {
clInfos = vehicleDAO.findWithPage(pager.getPageSize(), pager.getStartRow());
} catch (Exception ex) {
servlet.log(ex.toString());
return actionMapping.findForward(Constants.FAILURE);
}
//把輸出的記錄集和pager對象保存到request對象中
httpServletRequest.setAttribute("CLINFOS", clInfos);
httpServletRequest.setAttribute("PAGER", pager);
return actionMapping.findForward(Constants.SUCCESS);
}
查詢語句select count(*) from VehicleProperty 也可以換成你需要的任意的條件（select count(*) from VehicleProperty where ..)
Action二:
DisplayAllAction 顯示數(shù)據(jù)頁面控制器
package com.jeffrey.messagelove;
import com.jeffrey.messagelove.*;
import com.jeffrey.messagelove.Pager;
import com.jeffrey.messagelove.hibernate.*;
/*
* @(#)DisplayAction.java 2005-5-2
*
* Copyright (c) 2005, Jeffrey Xu
*/
import org.apache.struts.action.*;
import java.util.*;
import javax.servlet.http.*;
/**
* 顯示頁面控制器
*/
public class DisplayAllAction extends Action {
private HibernateDAO hibernateDAO = new HibernateDAO();
private Pager pager = new Pager();
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
HttpSession session = request.getSession();
List messageList = null;
HQuery hquery = new HQuery();
int totalRows = 0;
int startRow = 0;
try {
totalRows = hibernateDAO.getRows("select count(*) from Message");
// 初始化頁面信息
pager.init(totalRows, Constants.RECORD_PER_PAGE);
} catch (Exception ex) {
ex.printStackTrace();
}
hquery.setQueryString("From Message order by m_sendDate desc");
String viewPage = (String) request.getParameter("viewPage");
String action = (String) request.getParameter("action");
// 跳轉(zhuǎn)至相應(yīng)頁面
if (viewPage != null && !viewPage.equals("")) {
try {
pager.setCurrentPage(Integer.parseInt(viewPage));
} catch (NumberFormatException e) {
e.printStackTrace();
}
}
if (action != null) {
// 根據(jù)傳遞進來的參數(shù)控制頁面的前進后退
if (action.equalsIgnoreCase("previous")) {
pager.previous();
} else if (action.equalsIgnoreCase("next")) {
pager.next();
} else if (action.equalsIgnoreCase("first")) {
pager.first();
} else if (action.equalsIgnoreCase("last")) {
pager.last();
}
}
try {
hquery.setPageStartNo(pager.getCurrentPage());
messageList = hibernateDAO.find(hquery);
} catch (Exception ex) {
ex.printStackTrace();
}
request.setAttribute("list", messageList);
session.setAttribute("pager", pager);
return mapping.findForward("display");
}
}
Action中PagerHelp類以及DAO
package com.jpcf.db.helper;
import javax.servlet.http.*;
public class PagerHelper {
public static Pager getPager(HttpServletRequest httpServletRequest,
int totalRows) {
//定義pager對象，用于傳到頁面
Pager pager = new Pager(totalRows);
//從Request對象中獲取當(dāng)前頁號
String currentPage = httpServletRequest.getParameter("currentPage");
//如果當(dāng)前頁號為空，表示為首次查詢該頁
//如果不為空，則刷新pager對象，輸入當(dāng)前頁號等信息
if (currentPage != null) {
pager.refresh(Integer.parseInt(currentPage));
}
//獲取當(dāng)前執(zhí)行的方法，首頁，前一頁，后一頁，尾頁。
String pagerMethod = httpServletRequest.getParameter("pageMethod");
if (pagerMethod != null) {
if (pagerMethod.equals("first")) {
pager.first();
} else if (pagerMethod.equals("previous")) {
pager.previous();
} else if (pagerMethod.equals("next")) {
pager.next();
} else if (pagerMethod.equals("last")) {
pager.last();
}
}
return pager;
}
}
DAO類
package com.jpcf.db.dao;
import com.jpcf.db.model.*;
import com.jpcf.db.helper.HibernateUtil;
import net.sf.hibernate.*;
import java.util.*;
import com.jpcf.db.controller.*;
public class VehiclePropertyDAO {
public Collection findWithPage(int pageSize, int startRow) throws
HibernateException {
Collection vehicleList = null;
Transaction tx = null;
try {
Session session = HibernateUtil.currentSession();
tx = session.beginTransaction();
Query q = session.createQuery("from VehicleProperty vp");
q.setFirstResult(startRow);
q.setMaxResults(pageSize);
vehicleList = q.list();
tx.commit();
} catch (HibernateException he) {
if (tx != null) {
tx.rollback();
}
throw he;
} finally {
HibernateUtil.closeSession();
}
return vehicleList;
}
public int getRows(String query) throws
HibernateException {
int totalRows = 0;
Transaction tx = null;
try {
Session session = HibernateUtil.currentSession();
tx = session.beginTransaction();
totalRows = ((Integer) session.iterate(query).next()).
intValue();
tx.commit();
} catch (HibernateException he) {
if (tx != null) {
tx.rollback();
}
throw he;
} finally {
HibernateUtil.closeSession();
}
return totalRows;
}
}

最新評論