一个PHP分页类的代码

<?
/**
* filename: ext_page.class.php
* @package:phpbean
* @author :feifengxlq<feifengxlq#gmail.com><http://www.phpobject.net/>
* @copyright :Copyright 2006 feifengxlq
* @license:version 2.0
* @create:2006-5-31
* @modify:2006-6-1
* @modify:feifengxlq 2006-11-4
* description: 分页类，四种分页模式
* 2.0增加功能：支持自定义风格，自定义样式，同时支持PHP4和PHP5,
* to see detail,please visit http://www.phpobject.net/blog/read.php?
* example:
* 模式四种分页模式：
require_once(../libs/classes/page.class.php);
$page=new page(array(total=>1000,perpage=>20));
echo mode:1<br>.$page->show();
echo <hr>mode:2<br>.$page->show(2);
echo <hr>mode:3<br>.$page->show(3);
echo <hr>mode:4<br>.$page->show(4);
开启AJAX：
$ajaxpage=new page(array(total=>1000,perpage=>20,ajax=>ajax_page,page_name=>test));
echo mode:1<br>.$ajaxpage->show();
采用继承自定义分页显示模式：
demo:http://www.phpobject.net/blog
*/
class page
{
/**
* config ,public
*/
var $page_name="PB_page";//page标签，用来控制url页
var $next_page=>;//下一页
var $pre_page=<;//上一页
var $first_page=First;//首页
var $last_page=Last;//尾页
var $pre_bar=<<;//上一分页条
var $next_bar=>>;//下一分页条
var $format_left=[;
var $format_right=];
var $is_ajax=false;//是否支持AJAX分页模式

/**
* private
*
*/
var $pagebarnum=10;//控制记录条的个数 。
var $totalpage=0;//总页数
var $ajax_action_name=;//AJAX动作名
var $nowindex=1;//当前页
var $url="";//url地址头
var $offset=0;

/**
* constructor构造函数
*
* @param array $array[total],$array[perpage],$array[nowindex],$array[url],$array[ajax]
*/
function page($array)
{
if(is_array($array)){
if(!array_key_exists(total,$array))$this->error(__FUNCTION__,need a param of total);
$total=intval($array[total]);
$perpage=(array_key_exists(perpage,$array))?intval($array[perpage]):10;
$nowindex=(array_key_exists(nowindex,$array))?intval($array[nowindex]):;
$url=(array_key_exists(url,$array))?$array[url]:;
}else{
$total=$array;
$perpage=10;
$nowindex=;
$url=;
}
if((!is_int($total))||($total<0))$this->error(__FUNCTION__,$total. is not a positive integer!);
if((!is_int($perpage))||($perpage<=0))$this->error(__FUNCTION__,$perpage. is not a positive integer!);
if(!empty($array[page_name]))$this->set(page_name,$array[page_name]);//设置pagename
$this->_set_nowindex($nowindex);//设置当前页
$this->_set_url($url);//设置链接地址
$this->totalpage=ceil($total/$perpage);
$this->offset=($this->nowindex-1)*$perpage;
if(!empty($array[ajax]))$this->open_ajax($array[ajax]);//打开AJAX模式
}
/**
* 设定类中指定变量名的值，如果改变量不属于这个类，将throw一个exception
*
* @param string $var
* @param string $value
*/
function set($var,$value)
{
if(in_array($var,get_object_vars($this)))
$this->$var=$value;
else {
$this->error(__FUNCTION__,$var." does not belong to PB_Page!");
}

}
/**
* 打开倒AJAX模式
*
* @param string $action 默认ajax触发的动作 。
*/
function open_ajax($action)
{
$this->is_ajax=true;
$this->ajax_action_name=$action;
}
/**
* 获取显示"下一页"的代码
*
* @param string $style
* @return string
*/
function next_page($style=)
{
if($this->nowindex<$this->totalpage){
return $this->_get_link($this->_get_url($this->nowindex+1),$this->next_page,$style);
}
return <span class=".$style.">.$this->next_page.</span>;
}

/**
* 获取显示“上一页”的代码
*
* @param string $style
* @return string
*/
function pre_page($style=)
{
if($this->nowindex>1){
return $this->_get_link($this->_get_url($this->nowindex-1),$this->pre_page,$style);
}
return <span class=".$style.">.$this->pre_page.</span>;
}

/**
* 获取显示“首页”的代码
*
* @return string
*/
function first_page($style=)
{
if($this->nowindex==1){
return <span class=".$style.">.$this->first_page.</span>;
}
return $this->_get_link($this->_get_url(1),$this->first_page,$style);
}

/**
* 获取显示“尾页”的代码
*
* @return string
*/
function last_page($style=)
{
if($this->nowindex==$this->totalpage){
return <span class=".$style.">.$this->last_page.</span>;
}
return $this->_get_link($this->_get_url($this->totalpage),$this->last_page,$style);
}

function nowbar($style=,$nowindex_style=)
{
$plus=ceil($this->pagebarnum/2);
if($this->pagebarnum-$plus+$this->nowindex>$this->totalpage)$plus=($this->pagebarnum-$this->totalpage+$this->nowindex);
$begin=$this->nowindex-$plus+1;
$begin=($begin>=1)?$begin:1;
$return=;
for($i=$begin;$i<$begin+$this->pagebarnum;$i++)
{
if($i<=$this->totalpage){
if($i!=$this->nowindex)
$return.=$this->_get_text($this->_get_link($this->_get_url($i),$i,$style));
else
$return.=$this->_get_text(<span class=".$nowindex_style.">.$i.</span>);
}else{
break;
}
$return.="\n";
}
unset($begin);
return $return;
}
/**
* 获取显示跳转按钮的代码
*
* @return string
*/
function select()
{
$return=<select name="PB_Page_Select">;
for($i=1;$i<=$this->totalpage;$i++)
{
if($i==$this->nowindex){
$return.=<option value=".$i." selected>.$i.</option>;
}else{
$return.=<option value=".$i.">.$i.</option>;
}
}
unset($i);
$return.=</select>;
return $return;
}

/**
* 获取mysql 语句中limit需要的值
*
* @return string
*/
function offset()
{
return $this->offset;
}

/**
* 控制分页显示风格
*
* @param int $mode
* @return string
*/
function show($mode=1)
{
switch ($mode)
{
case 1:
$this->next_page=下一页;
$this->pre_page=上一页;
return $this->pre_page().$this->nowbar().$this->next_page().第.$this->select().页;
break;
case 2:
$this->next_page=下一页;
$this->pre_page=上一页;
$this->first_page=首页;
$this->last_page=尾页;
return $this->first_page().$this->pre_page().[第.$this->nowindex.页].$this->next_page().$this->last_page().第.$this->select().页;
break;
case 3:
$this->next_page=下一页;
$this->pre_page=上一页;
$this->first_page=首页;
$this->last_page=尾页;
return $this->first_page().$this->pre_page().$this->next_page().$this->last_page();
break;
case 4:
$this->next_page=下一页;
$this->pre_page=上一页;
return $this->pre_page().$this->nowbar().$this->next_page();
break;
case 5:
return $this->pre_bar().$this->pre_page().$this->nowbar().$this->next_page().$this->next_bar();
break;
}

}
/*----------------private function (私有方法)-----------------------------------------------------------*/
/**
* 设置url头地址
* @param: String $url
* @return boolean
*/
function _set_url($url="")
{
if(!empty($url)){
//手动设置
$this->url=$url.((stristr($url,?))?&:?).$this->page_name."=";
}else{
//自动获取
if(empty($_SERVER[QUERY_STRING])){
//不存在QUERY_STRING时
$this->url=$_SERVER[REQUEST_URI]."?".$this->page_name."=";
}else{
//
if(stristr($_SERVER[QUERY_STRING],$this->page_name.=)){
//地址存在页面参数
$this->url=str_replace($this->page_name.=.$this->nowindex,,$_SERVER[REQUEST_URI]);
$last=$this->url[strlen($this->url)-1];
if($last==?||$last==&){
$this->url.=$this->page_name."=";
}else{
$this->url.=&.$this->page_name."=";
}
}else{
//
$this->url=$_SERVER[REQUEST_URI].&.$this->page_name.=;
}//end if
}//end if
}//end if
}

/**
* 设置当前页面
*
*/
function _set_nowindex($nowindex)
{
if(empty($nowindex)){
//系统获取

if(isset($_GET[$this->page_name])){
$this->nowindex=intval($_GET[$this->page_name]);
}
}else{
//手动设置
$this->nowindex=intval($nowindex);
}
}

/**
* 为指定的页面返回地址值
*
* @param int $pageno
* @return string $url
*/
function _get_url($pageno=1)
{
return $this->url.$pageno;
}

/**
* 获取分页显示文字，比如说默认情况下_get_text(<a href="">1</a>)将返回[<a href="">1</a>]
*
* @param String $str
* @return string $url
*/
function _get_text($str)
{
return $this->format_left.$str.$this->format_right;
}

/**
* 获取链接地址
*/
function _get_link($url,$text,$style=){
$style=(empty($style))?:class=".$style.";
if($this->is_ajax){
//如果是使用AJAX模式
return <a .$style. href="javascript:.$this->ajax_action_name.(\.$url.\)">.$text.</a>;
}else{
return <a .$style. href=".$url.">.$text.</a>;
}
}
/**
* 出错处理方式
*/
function error($function,$errormsg)
{
die(Error in file <b>.__FILE__.</b> ,Function <b>.$function.()</b> :.$errormsg);
}
}
$page=new page(array(total=>1000,perpage=>20));
echo mode:1<br>.$page->show();
echo <hr>mode:2<br>.$page->show(2);
echo <hr>mode:3<br>.$page->show(3);
echo <hr>mode:4<br>.$page->show(4);
echo <hr>开始AJAX模式:;
$ajaxpage=new page(array(total=>1000,perpage=>20,ajax=>ajax_page,page_name=>test));
echo mode:1<br>.$ajaxpage->show();
?>