使用Hibernate分页有关问题

2012-07-15

使用Hibernate分页问题使用hibernate调用自己的分页类第一页数据出来了但是没有下一页的数据页码也没有走

使用Hibernate分页问题
使用hibernate调用自己的分页类第一页数据出来了但是没有下一页的数据页码也没有走断点总记录数和页码的分组数都计算出来了
这是分页类
package cn.jbit.renting.bean;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

/**
* Java Bean
* @author Administrator
*
*/
public class Pager implements Serializable{

//public static final int PAGE_RECORD = 6;
public static final int GROUP_RECORD = 5;//显示几组
public static int page_record;//每页显示几条数据
private int currentPage;// 当前页码
private int pageCount;// 总页数
private int recordCount;// 总记录数

private int currentGroup;// 当前组数
private int groupCount;// 总组数
private List<Integer> groupList;// 页面中需要的分组页索引
public int prevPage;
public int nextPage;

public int getPage_record() {
return page_record;
}

public void setPage_record(int page_record) {
this.page_record = page_record;
}

// 构造函数
public Pager(int page){
currentPage = page;
}

// 获取当前页页码
public int getCurrentPage(){
return currentPage;
}

// 获取下一页页码
public int getNextPage(){
if(currentPage < pageCount)
return currentPage+1;
else
return pageCount;
}
// 获取上一页页码
public int getPrevPage(){
if(currentPage <= 1)
return 1;
else
return currentPage - 1;
}

// 获取当前组数
public int getCurrentGroup(){
return currentGroup;
}

public List<Integer> getGroupList(){
// 计算当前组数
currentGroup = (int)Math.ceil((float)currentPage / GROUP_RECORD);

groupList = new ArrayList<Integer>();
int start = (currentGroup-1) * GROUP_RECORD;
int end = (start + GROUP_RECORD) < pageCount ? start + GROUP_RECORD : pageCount;
for (int i = start + 1; i <= end; i++) {
groupList.add(i);
}
return groupList;
}

// 获取总页数
public int getPageCount(){
return pageCount;
}

// 设置总记录数
public void setRecordCount(int recordCount) {
this.recordCount = recordCount;
pageCount = (int)Math.ceil(((float)recordCount / page_record));
}

// 获取总记录数
public int getRecordCount() {
return recordCount;
}
}

方法调用
/***
* 分页
*/
public List<House> SearchpageHouse(Pager pager) {
if(pager.getRecordCount() == 0){
pager.setRecordCount(getHouse().size());//总共多少条记录
}
String hql="from House";

Query query=session.createQuery(hql);
int start=(pager.getCurrentPage() - 1) * Pager.page_record;//起始位置
query.setFirstResult(start);
query.setMaxResults(start + Pager.page_record);//结束为止

List<House> list=query.list();
return list;

}

servlet里的调用
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html;UTF-8");
response.setCharacterEncoding("UTF-8");
request.setCharacterEncoding("UTF-8");
PrintWriter out = response.getWriter();
//HouseBiz house=new HouseBizImpl();
//List<House> houses=house.getHouse();
//request.setAttribute("houses", houses);
//request.getRequestDispatcher("MyJsp.jsp").forward(request, response);
HouseBiz hb=new HouseBizImpl();
String page=request.getParameter("page");
int p=1;
if(page!=null&&!(page.equals("")))
{
p=Integer.parseInt(page);
}
Pager pager=new Pager(p);
pager.setPage_record(3);//每页显示三条记录

//int size=2;
//List<House> list=hb.getpageHouse(index, size);

List<House> list=hb.SearchpageHouse(pager);
//int count=hb.getHouse().size();
//int topage=(count%size==0)?(count/size):(count/size+1);
//request.setAttribute("topage", topage);//最大页码
request.setAttribute("houses", list);
//request.setAttribute("index", index);//当前页码
request.setAttribute("paper", pager);
request.getRequestDispatcher("MyJsp.jsp").forward(request, response);
}
jsp页面

<table>
<c:forEach items="${houses}" var="houses">
<tr >
<td rowspan="3" style="width:50px"><img src="images/thumb_house.gif" /></td>
<td style="width:400px">${houses.title}</td>
<c:if test="${user!=null}">
<c:if test="${houses.user_id.id==user.id}">
<td rowspan="3" style="width:100px"><a>修改</a></td>
<td rowspan="3" style="width:100px"><a href="javascript:deleteHouse(${houses.id})">删除</a></td>
</c:if>
</c:if>
</tr>
<tr>
<td style="width:400px">${houses.street_id.name}--${houses.street_id.distrct_ID.name}</td>
</tr>
<tr>
<td style="width:400px">联系电话:${houses.contact}</td>
</tr>
</c:forEach>

</table>

<a href="GetItem?page=${requestScope.pager.prevPage }">上一页</a>
<c:forEach items="${requestScope.pager.groupList }" var="i">
<c:if test="${ i == pager.currentPage }">
${i}
</c:if>
<c:if test="${ i != pager.currentPage }">
<a href="GetItem?page=${i}">${i }</a>
</c:if>
</c:forEach>
<a href="GetItem?page=${requestScope.pager.nextPage }">下一页</a>
</div>

[解决办法]
提供给你一个万能分页类，只需要输入一个HQL语句即可实现分页

public class PagingModel {

private static Log logger = LogFactory.getLog(PagingModel.class);

/**
* 此hql只接受 select t from(FROM) 类的查询
* @param session
* @param hql
* @param currentPage
* @param pageSize
* @return
* @throws Exception
*/
public static PageController findPage(Session session, String hql ,long currentPage,
int pageSize) throws Exception {
logger.trace("entering");

long number = getRSCount(session, hql);
PageController page = findPage(number, session, hql, currentPage, pageSize);

logger.trace("exiting");
return page;
}

/**
* 此hql可以接受 select distinct .. from(FROM) 类的查询
* @param session
* @param hql
* @param currentPage
* @param pageSize
* @return
* @throws Exception
*/
public static PageController findPage2(Session session, String hql ,long currentPage,
int pageSize) throws Exception {
logger.trace("entering");

long number = getRSCount2(session, hql);
PageController page = findPage(number, session, hql, currentPage, pageSize);

logger.trace("exiting");
return page;
}

private static PageController findPage(long number, Session session, String hql ,long currentPage,
int pageSize) throws Exception {
logger.trace("entering");

long countPage = getMemberPageCount(number, pageSize);
if (currentPage > countPage) {
currentPage = countPage;
} else if (currentPage < 1) {
currentPage = 1L;
}
long firstNumber = (currentPage - 1) * pageSize;
if (firstNumber > number) {
firstNumber = (int)number;
}

Query query = session.createQuery(hql);
query.setFirstResult((int) firstNumber);
query.setMaxResults(pageSize);
List list = query.list();
PageController page = new PageController();
page.setTotalRecord(number);// 共多少记录
page.setCurPage((int) currentPage);// 当前页
page.setLastPage((int) countPage);// 共多少页
page.setResults(list);// 当前页的内容

logger.trace("exiting");
return page;
}

/**
* 获取当前查询共有多少页
* @param count
* @param pageCount
* @return
* @throws Exception
*/
private static long getMemberPageCount(long count, int pageSize) throws Exception{
logger.trace("entering");
long countPage = 0;

if(count % pageSize == 0){
countPage = count / pageSize;
}else{
countPage = count / pageSize + 1;
}

logger.trace("exiting");
return countPage;
}

/**
* 获取当前查询共有多少条记录
* @param session
* @param hql
* @return
* @throws Exception
*/
private static long getRSCount(Session session, String hql) throws Exception{

StringBuffer buffer = new StringBuffer();
int index = hql.indexOf("FROM") == -1 ? hql.indexOf("from") : hql.indexOf("FROM");
buffer.append("SELECT count(*) ");
buffer.append(hql.substring(index, hql.length()));

Query query = session.createQuery(buffer.toString());
Object o = query.uniqueResult();
Long l = Long.valueOf(o.toString());

logger.trace("exiting");
return l.longValue();
}

/**
* 获取当前查询共有多少条记录
* @param session
* @param hql
* @return
* @throws Exception
*/
private static long getRSCount2(Session session, String hql) throws Exception{
logger.trace("entering");

StringBuffer buffer = new StringBuffer();
int index_from = hql.indexOf("FROM") == -1 ? hql.indexOf("from") : hql.indexOf("FROM");
int index_distinct = hql.indexOf("DISTINCT") == -1 ? hql.indexOf("distinct") : hql.indexOf("DISTINCT");
int index_order = hql.indexOf("ORDER") == -1 ? hql.indexOf("order") : hql.indexOf("ORDER");
buffer.append("SELECT count(").append(hql.substring(index_distinct, index_from)).append(") ");
if (index_order < 0) {
buffer.append(hql.substring(index_from, hql.length()));
} else {
buffer.append(hql.substring(index_from, index_order));
}

Query query = session.createQuery(buffer.toString());
Object o = query.uniqueResult();
Long l = Long.valueOf(o.toString());

logger.trace("exiting");
return l.longValue();
}
}

public class PageController {
public final static int PAGE_SIZE = 10;

private List results;

private int curPage = 1;

private int perPage = 20;

private int prePage;

private int nextPage;

private int firstPage = 1;

private int lastPage;

private int recordStart = 1;

private long totalRecord = 0;

public PageController() {

}

public PageController(List results, int totalCount, Integer curPage,
Integer perPage) {
this.results = results;

if (totalCount > 0) {
this.totalRecord = totalCount;
}

if (perPage != null && perPage.intValue() > 0) {
this.perPage = perPage.intValue();
}

if (curPage != null && curPage.intValue() > 0) {
this.curPage = curPage.intValue();
}

if (this.curPage < 1) {
this.curPage = 1;
}

this.lastPage = (totalCount / this.perPage);
if (totalCount % this.perPage != 0) {
this.lastPage += 1;
}

if (this.curPage > this.lastPage) {
this.curPage = this.lastPage;
}

this.prePage = (this.curPage > 1) ? (this.curPage - 1) : 1;

this.nextPage = (this.curPage == this.lastPage) ? this.lastPage
: (this.curPage + 1);

recordStart = (this.curPage - 1) * this.perPage + 1;
}

public int getCurPage() {
return curPage;
}

public void setCurPage(int curPage) {
this.curPage = curPage;
}

public int getFirstPage() {
return firstPage;
}

public void setFirstPage(int firstPage) {
this.firstPage = firstPage;
}

public int getLastPage() {
return lastPage;
}

public void setLastPage(int lastPage) {
this.lastPage = lastPage;
}

public int getNextPage() {
return nextPage;
}

public void setNextPage(int nextPage) {
this.nextPage = nextPage;
}

public int getPerPage() {
return perPage;
}

public void setPerPage(int perPage) {
this.perPage = perPage;
}

public int getPrePage() {
return prePage;
}

public void setPrePage(int prePage) {
this.prePage = prePage;
}

public int getRecordStart() {
return recordStart;
}

public void setRecordStart(int recordStart) {
this.recordStart = recordStart;
}

public List getResults() {
return results;
}

public void setResults(List results) {
this.results = results;
}

public long getTotalRecord() {
return totalRecord;
}

public void setTotalRecord(long totalRecord) {
this.totalRecord = totalRecord;
}

public String getNavBar(String url, String param) {
StringBuffer str = new StringBuffer(url);
if (StringUtils.isEmpty(url)) {
return url.toString();
}

if (url.indexOf("?") != -1) {
str.append("&");
} else {
str.append("?");
}
str.append(param).append("=");

StringBuffer nav = new StringBuffer();
nav.append("共 ").append(totalRecord).append(
" 条记录    第 ").append(curPage)
.append(" 页 / 共 ").append(lastPage).append(
" 页    ");
nav.append("<a href=\"").append(str).append(this.firstPage).append(
"\">首页</a>    ");
nav.append("<a href=\"").append(str).append(this.prePage).append(
"\">上一页</a>    ");
nav.append("<a href=\"").append(str).append(this.nextPage).append(
"\">下一页</a>    ");
nav.append("<a href=\"").append(str).append(this.lastPage).append(
"\">尾页</a>    ");

return nav.toString();
}
}

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