php分页类 增强版

<?php//==============分页类的实现===============/* *@param  *$pageSize    每页大小 *$sumRecord   总记录条数 *$sumPage     总页数 *$currentPage 当前页数 *$url         页面的url地址 *$num         分页的数字显示个数 */class Page{    private $pageSize;    private $sumRecord;    private $sumPage;    private $currentPage;    private $url;    private $num;      public function __construct($sumRecord, $pageSize, $currentPage, $num=5)    {$this->pageSize    = $pageSize;$this->sumRecord   = $sumRecord;$this->currentPage = $currentPage;$this->num         = $num;$this->sumPage = ceil($this->sumRecord/$this->pageSize);$this->getUrl();    }        private function first()   //首页    {if($this->currentPage !=1 ){    return "<a href='".$this->url."1'>首页</a>\n";} else {    return "首页\n";}    }    private function prevPage()//上一页    {if($this->currentPage > 1){    return "<a href='".$this->url.($this->currentPage-1)."'>上一页</a>\n";} else {    return "上一页\n";}    }    private function middle()//中间的数字页面    {$middleStr = "";$start     = 1;if($this->currentPage >=1 && $this->currentPage <= floor($this->num/2)+1) {//当前面小于显示页数的一半时 显示前num个    for($i=1; $i <= $this->num && $i <= $this->sumPage; $i++) {if($i == $this->currentPage){    $middleStr .=$i."\n";} else {    $middleStr .="<a href='".$this->url.$i."'>".$i."</a>\n";}    }}else if($this->currentPage >= ($this->sumPage- floor($this->num/2) ) ) {//当前面大于（总页数）减去（显示页数的一半）时 显示后num个    if(($this->sumPage - $this->num) > 0) {$start = $this->sumPage - $this->num + 1;    } else {$start =1;    }    for($i= $start; $i <= $this->sumPage; $i++) {if($i == $this->currentPage){    $middleStr .=$i."\n";} else {    $middleStr .="<a href='".$this->url.$i."'>".$i."</a>\n";}    }} else {    $start = $this->currentPage - floor($this->num/2) ;    for($i = $start; $i < $start + $this->num; $i++) {if($i == $this->currentPage){    $middleStr .=$i."\n";} else {    $middleStr .="<a href='".$this->url.$i."'>".$i."</a>\n";}    }}return $middleStr;    }    private function postPage()//下一页    {if($this->currentPage < $this->sumPage){    return "<a href='".$this->url.($this->currentPage+1)."'>下一页</a>\n";} else {    return "下一页\n";}    }    private function last()   //尾页    {if($this->currentPage != $this->sumPage){    return "<a href='".$this->url.$this->sumPage."'>尾页</a>\n";} else {    return "尾页\n";}    }        private function getUrl()    {$url   = $_SERVER['REQUEST_URI'];$param = parse_url($url);if(isset($param['query'])) {    parse_str($param['query'],$query);       unset($query['page']);    if(count($query)) {$this->url = $param['path']."?".http_build_query($query)."&page=";    } else {$this->url = $param['path']."?page=";    }} else {    $this->url = $param['path']."?page=";}    }    public function showPaging()    {$str = "第{$this->currentPage}/{$this->sumPage}页 共{$this->sumRecord}条记录\n";$str .= $this->first();$str .= $this->prevPage();$str .= $this->middle();$str .= $this->postPage();$str .= $this->last();echo $str;    }}$page  = isset($_GET['page'])? $_GET['page']: 1;$pager = new Page(201, '20', $page);$pager->showPaging();