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();