一个用JSP实现的分页的类及调用方法

//PageCt.java 分页的类
/*
*** @version ***********
*** Created on 2001年6月25日, 下午14:41
**************************************
*/
package vod;
import java.sql.*;
import java.util.*;

public class PageCt
{
private long l_start; //开始纪录
private long l_end; //结束纪录
private long l_curpage; //当前页数
private long l_totalnum;//总记录数
private int int_num=5; //每页10条
private long l_totalpage; //总的页数

public void Init(long currentpage,long totalnum)
{
l_curpage = currentpage;
l_totalnum = totalnum;

if (currentpage＞=0)
{
if (currentpage＞=(long)Math.ceil((double)l_totalnum/(double)int_num))
l_curpage = (long)Math.floor((double)l_totalnum/(double)int_num);
else
l_curpage = currentpage;
}
else
{
l_curpage = 0;
}
l_start = l_curpage * int_num;
l_end = l_start + int_num;
if (l_end ＞ l_totalnum)
l_end = l_totalnum;
l_totalpage = (long)Math.ceil((double)l_totalnum/(double)int_num);
}
public long getCurpage()
{
return l_curpage;
}
public long getPrepage()
{
if (l_curpage-1＞=0)
{
return l_curpage-1;
}
else
{
return 0;
}
}
public long getNextpage()
{
if (l_curpage+1＜=l_totalpage)
{
return l_curpage+1;
}
else
{
return l_totalpage;
}
}
public long getTotalnum()
{
return l_totalnum;
}
public long getTotalpage()
{
return l_totalpage;
}
public long getStart()
{
return l_start;
}
public long getEnd()
{
return l_end;
}

};
===============================================
//调用例子
＜%
/*
*** @author 马毅 ***********
*** @version ***********
*** Created on 2001年6月12日, 下午17:13
**************************************
*/
＜%@ page import="java.sql.*"%＞
＜%@ page import="java.lang.*"%＞
＜%@ page contentType="text/html;charset=gb2312" %＞
＜jsp:useBean id="PageCount" scope="page" class="kstest.PageCt" /＞
＜jsp:useBean id="sqlbean" scope="page" class="vod.sql_data" /＞
＜html＞
＜head＞
＜TITLE＞测试＜/TITLE＞
＜STYLE＞
body,table{font-size:9pt}
A:link {
COLOR: #000084; TEXT-DECORATION: none
}
A:visited {
COLOR: #000084; TEXT-DECORATION: none
}
A:hover {
COLOR: black; TEXT-DECORATION: underline
}
.ourfont {
FONT-SIZE: 9pt
}
＜/STYLE＞
＜/head＞
＜body bgcolor=#eff3ff＞
＜center＞
＜font color=#000084＞＜h3＞Test for Test＜/h3＞＜/font＞
＜hr width=600 color=#b5dbff＞
＜br＞
＜%
ResultSet rs0 = sqlbean.executeQuery("select count(*) from UserList );
rs0.next();
long data_num=rs0.getLong(1);
long Current_Page = 0;
String currentpage=(String)request.getParameter("currentpage");
if (currentpage != null && !currentpage.equals(""))
{
Current_Page = Integer.parseInt(request.getParameter("currentpage"));
}
String Query_Page=(String)request.getParameter("Query_Page");
if (Query_Page!=null && !Query_Page.equals(""))
{
Current_Page = Integer.parseInt(request.getParameter("Query_Page"))-1;
}
PageCt.Init(Current_Page,data_num);
long l_start = PageCt.getStart();
long l_end = PageCt.getEnd();
//查询记录
ResultSet rs = sqlbean.executeQuery("select * from UserList " );
long i=0;
while((i＜l_start) && rs.next())
{
i++;
}
//输出查询结果
long j=0;
while(rs.next() && (i＜l_end))
{
j=i+1;
String col2 = rs.getString(2);
String col3 = rs.getString(3);
String col4 = rs.getString(4);
String col5 = rs.getString(5);
String col6 = rs.getString(6);
String col7 = rs.getString(7);
String col8 = rs.getString(8);
//打印所显示的数据
out.println("＜table border=0 width=600＞");
out.println("＜tr＞＜td colspan=2＞＜font color=#000084＞" + j + "、"+(col2==null?"":col2)+"＜/font＞＜/td＞＜/tr＞＜tr＞＜td colspan=2＞答案："+(col3==null?"":col3)+"＜/td＞＜/tr＞");
out.println("＜tr＞＜td＞  选项1："+(col4==null?"":col4)+"＜/td＞＜td＞  选项2："+(col5==null?"":col5)+"＜/td＞＜/tr＞");
out.println("＜tr＞＜td＞  选项3："+(col6==null?"":col6)+"＜/td＞＜td＞  选项4："+(col7==null?"":col7)+"＜/td＞＜/tr＞");
if (col8!=null && !col8.equals(""))
{
out.println("＜tr＞＜td colspan=2＞备注："+col8+"＜/td＞＜/tr＞");
}
out.println("＜/table＞＜br＞");
i++;
}
%＞
＜table width=600＞
＜tr bgcolor=#b5dbff＞
＜form method=GET action=index.jsp＞
＜td width=80 align=center valign=bottom＞共 ＜%=PageCt.getTotalnum()%＞ 条＜/td＞
＜td width=80 align=center valign=bottom＞＜%=PageCt.getCurpage()+1%＞/＜%=PageCt.getTotalpage()%＞ 页＜/td＞
＜td width=120 align=center＞查看第 ＜input type=text name=Query_Page size=3＞ 页＜/td＞
＜td width=50 align=center valign=bottom＞＜a href=index.jsp?currentpage=＜%=PageCt.getPrepage()%＞＞上页＜/a＞＜/td＞
＜td width=50 align=center valign=bottom＞＜a href=index.jsp?currentpage=＜%=PageCt.getNextpage()%＞＞下页＜/a＞
＜/td＞
＜/tr＞
＜/table＞
＜br＞＜br＞＜br＞
＜table cellspacing=20＞
＜tr＞
＜td＞问题包含＜input type=text name=question_str size=10 value=＜% if (question_str != null) out.println(question_str); %＞ ＞＜/td＞
＜td＞答案包含＜input type=text name=answer_str size=10 value=＜% if (answer_str != null) out.println(answer_str); %＞ ＞＜/td＞
＜td＞选项包含＜input type=text name=sel_str size=10 value=＜% if (sel != null) out.println(sel); %＞ ＞＜/td＞
＜/tr＞
＜tr＞
＜td colspan=3 align=center＞＜input type=submit value=查询＞＜/td＞
＜/tr＞
＜/form＞
＜/table＞
＜br＞＜br＞
＜a href="insert.jsp"＞添加＜/a＞
＜center＞
＜/body＞
＜/html＞

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