分頁類系列之三

分页类之三

class Page {
	private $total; //查询所有的数据总记录数
	private $page; //当前第几页
	private $num; //每页显示记录的条数
	private $pageNum; //一共多少页
	private $offset; //从数据库中取记录的开始偏移数

	function __construct($total, $page=1, $num=5) {
		$this->total=$total;
		$this->page=$page;
		$this->num=$num;
		$this->pageNum=$this->getPageNum();
		$this->offset=$this->getOffset();
	}

	private function getPageNum(){
		return ceil($this->total/$this->num);
	}

	private function getNextPage() {
		if($this->page==$this->pageNum)
		return false;
		else
		return $this->page+1;
	}

	private function getPrevPage() {
		if($this->page==1)
		return false;
		else
		return $this->page-1;
	}
	//数据库查询的偏移量
	private function getOffset() {
		return ($this->page-1)*$this->num;
	}
	//当前页开始的记录数
	private function getStartNum() {
		if($this->total==0)
		return 0;
		else
		return $this->offset+1;
	}
	//当前页结束的记录数
	private function getEndNum() {
		return min($this->offset+$this->num,$this->total);
	}

	public function getPageInfo(){
		$pageInfo=array(
		"row_total" => $this->total,
		"row_num" => $this->num,
		"page_num" => $this->getPageNum(),
		"current_page" => $this->page,
		"row_offset" => $this->getOffset(),
		"next_page" => $this->getNextPage(),
		"prev_page" => $this->getPrevPage(),
		"page_start" => $this->getStartNum(),
		"page_end" => $this->getEndNum()
		);
		return $pageInfo;
	}
}
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