自己写的php分页类

<?php
class page {
    private $pageSize;
    private $countNum;
    private $pageCount;
    private $currentPage;
    private $showNumCount; //要显示的数字链接的个数
    public $start; //开始位置
    private $prev; //上一页链接
    private $next; //下一页链接
    private $num;
    public $pageStr;
    private $top;
    private $bottom;
    private $select;
    private $url;
    
    //构造函数
     function __construct($countNum, $pageSize = 5) {
        $this->url=$this->getURL();
         $this->countNum = $countNum;
        $this->pageSize = $pageSize;
        $this->pageCount = ceil ( ($this->countNum) / ($this->pageSize) );
        $this->currentPage = $this->getCurrentPage ();
        $this->getStart ();
        $this->getPagePrevAndNext ();
        $this->getPageNum ();
        $this->getTopAndBottom();
        $this->select=$this->getSelect();
        
        $this->mkPage();
        
    }
    
    //获得当前页函数
    private function getCurrentPage() {
        if (isset ( $_GET ["page"] ) && ! empty ( $_GET ["page"] )) {
            $page = $_GET ["page"];
            if ($page < 1) {
                $page = 1;
            }
            if ($page > $this->pageCount) {
                $page = $this->pageCount;
            }
        } else {
            $page = 1;
        }
        return $page;
    }
    
    //获得开始位置函数
    private function getStart() {
        $this->start = ($this->currentPage - 1) * $this->pageSize;
    }
    
    //获得get字符串
    private function  getURL(){
        $url="";
        
        foreach ($_GET as $key=>$val){
            if($key!="page"){
        $url==""?$url.=$key."=".$val:$url.="&".$key."=".$val;
        }
        }
        return  $url."&";
    }
    
    //获得上一页下一页链接函数
    private function getPagePrevAndNext() {
        $pagePrev = $this->currentPage - 1>0?$this->currentPage-1:1;
        $pageNext = $this->currentPage + 1>$this->pageCount?$this->pageCount:$this->currentPage+1;
        
        $this->prev = "<a href='?{$this->url}page=$pagePrev'>上一页</a>";
        $this->next = "<a href='?{$this->url}page=$pageNext'>下一页</a>";
    }
    
    //获得数字链接函数
    public  function getPageNum($showNumCount = 11) {
        $str = "";
        $this->showNumCount = $showNumCount;
        if (($this->showNumCount) > ($this->pageCount)) {
            for($i = 1; $i <= ($this->pageCount); $i ++) {
                if ($i == $this->currentPage) {
                    $str .= $i . "&nbsp;";
                } else {
                    $str .= "<a href='?{$this->url}page=$i'>$i</a>&nbsp;";
                }
            }
        } else {
            $step= round(($this->showNumCount-1)/2);
            if (($this->currentPage) < $step||($this->currentPage)==$step) {
                for($i = 1; $i <= $this->showNumCount; $i ++) {
                    if ($i == $this->currentPage) {
                        $str .= $i . "&nbsp;";
                    } else {
                        $str .= "<a href='?{$this->url}page=$i'>$i</a>&nbsp;";
                    }
                }
            } elseif ($step + ($this->currentPage) > $this->pageCount) {
                for($i = ($this->pageCount - $this->showNumCount + 1); $i <= $this->pageCount; $i ++) {
                    if ($i == $this->currentPage) {
                        $str .= $i . "&nbsp;";
                    } else {
                        $str .= "<a href='?{$this->url}page=$i'>$i</a>&nbsp;";
                    }
                }
            } else {
                for($i = $this->currentPage - $step; $i <= $this->currentPage + $step; $i ++) {
                    if ($i == $this->currentPage) {
                        $str .= $i . "&nbsp;";
                    } else {
                        $str .= "<a href='?{$this->url}page=$i'>$i</a>&nbsp;";
                    }
                }
            }
        }
        $this->num = $str;
    }
    
    //获得首位页链接
    private function getTopAndBottom(){
        $this->top=$this->currentPage==1?"":"<a href='?{$this->url}page=1'>首页</a>";
        $this->bottom=$this->currentPage==$this->pageCount?"":"<a href='?{$this->url}page={$this->pageCount}'>尾页</a>";
    }
    
    //获得下拉列表链接
    private function getSelect(){
        $str="总共{$this->pageCount}页&nbsp;";
        $str.="当前第";
        $str.="<script type=\"text/javascript\">function selectsubmit(val){window.location.href='?{$this->url}page='+val}</script>
        <select id=\"selectlist\" onchange=\"selectsubmit(this.value);\">";
        for ($i=1;$i<=$this->pageCount;$i++){
             $selected=$i==($this->currentPage)?"selected='selected'":"";
        $str.="<option $selected value='$i'>$i</option>";
        }
        $str.="</select>";
        $str.="页";
        return $str;
    }

    //生成分页链接
    function mkPage() {
        $this->pageStr =$this->top."&nbsp;". $this->prev . "&nbsp;" . $this->num . "&nbsp;" . $this->next."&nbsp;".$this->bottom."&nbsp;{$this->select}";
    }

}
?>