PHP实现适用于文件内容操作的分页类

<?php class StrPage { private $current;  //当前页  private $file;  //操作文件 private $totalPage;  //总的页数 private $url;  //传递的参数 private $pageLen;  //每页显示的长度  function __construct( $file,$len = 200 ){ $this->file = file_get_contents($file); $this->pageLen = $len; $this->current = isset($_GET['page'])?$_GET['page']:1; $this->totalPage = $this->getTotalPage(); $this->url = $this->getUrl(); }   //获取到这个文件总的长度 private function getTotalPage(){ return ceil(strlen($this->file)/$this->pageLen); }  //获取当前传递的参数,保留参数，page参数动态变化 private function getUrl(){ $url =parse_url($_SERVER['REQUEST_URI']); parse_str($url['query'],$queryArr); unset($queryArr['page']); $queryStr = http_build_query($queryArr); return $url['path'].'?'.$queryStr.'&page=';  }   //首页 private function first(){ if($this->current>1)  return "<a href='".$this->url."1'>首页</a>"; } //上一页 private function pre(){ if( $this->current > 1 )  return "<a href='".$this->url.($this->current-1)."'>上一页</a>"; } //下一页 private function next(){ if( $this->current < $this->totalPage)  return "<a href='".$this->url.($this->current+1)."'>下一页</a>"; } //最后一页 private function end(){ if( $this->current < $this->totalPage )  return "<a href='".$this->url.$this->totalPage."'>末页</a>"; }  public function pageList(){ $pageListStr = ''; for ($i=1;$i<=$this->totalPage;$i++){  if($i==$this->current){  $pageListStr.="<span style='font-size:20px;color:#f00'>".$i."</span> ";  }else{  $pageListStr.="<a href='".$this->url.$i."'>".$i." </a>";  } } return $pageListStr; }  public function pageStyle($style=1){  switch ($style){  case 1:   return "共有".$this->totalPage."页".$this->first().$this->pre().$this->pageList().$this->next().$this->end();   break;  case 2;  return $this->pageList();  break;  } }  public function getContents(){ $prePageLen = strlen($this->subStrs($this->current-1)); $currentPageLen = strlen($this->subStrs($this->current)); return substr($this->file, $prePageLen,$currentPageLen-$prePageLen); }  public function subStrs($page){   $string = '';  $len= $page*$this->pageLen;  for( $i=0; $i<$len; $i++ ){   if( ord(substr($this->file,$i,1))>0xa0 ){   $string .= substr($this->file,$i,3);   $i = $i+2;  }else{   $string .= substr($this->file, $i,1);  }  }  return $string;   } }