php实现分页功能的3种方法第1/3页

直接上代码，希望大家仔细阅读。

方法一：讲sql查询进行分页进行，需要调用几个函数，具体见脚本：
1.pager.class.php

<?php    class pager {    public $sql; //SQL查询语句    public $datanum; //查询所有的数据总记录数    public $page_size; //每页显示记录的条数    protected $_errstr;    protected $_conn;    protected $_query_id;    public function query($query)///这个函数有问题，暂时可以不用    {    $ret = false;    if (!empty($query)) {      if ($this->_conn === false || !is_resource($this->_conn)) {       warningLog(__METHOD__ . ': query sql with no connection', true);      return false;      }    $this->_query_id = @mysql_query($query, $this->_conn);    if ($this->_query_id === false) {    $this->_errstr = @mysql_error();    $ret = false;     } else {    $this->_errstr = 'SUCCESS';    $ret = $this->_query_id;      }    }     $msg = ($ret === false) ? 'false' : strval($ret);     debugLog(__METHOD__.": [$msg] returned for sql query [$query]");    return $ret;    }function __construct($sql,$page_size) {      $result = mysql_query($sql);      $datanum = mysql_num_rows($result);      $this->sql=$sql;      $this->datanum=$datanum;      $this->page_size=$page_size;    }    //当前页数    public function page_id() {      if($_SERVER['QUERY_STRING'] == ""){        return 1;      }elseif(substr_count($_SERVER['QUERY_STRING'],"page_id=") == 0){        return 1;      }else{        return intval(substr($_SERVER['QUERY_STRING'],8));      }    }    //剩余url值    public function url() {      if($_SERVER['QUERY_STRING'] == ""){        return "";      }elseif(substr_count($_SERVER['QUERY_STRING'],"page_id=") == 0){        return "&".$_SERVER['QUERY_STRING'];      }else{        return str_replace("page_id=".$this->page_id(),"",$_SERVER['QUERY_STRING']);      }    }    //总页数    public function page_num() {      if($this->datanum == 0){        return 1;      }else{        return ceil($this->datanum/$this->page_size);      }    }//数据库查询的偏移量    public function start() {      return ($this->page_id()-1)*$this->page_size;    }    //数据输出    public function sqlquery() {      return $this->sql." limit ".$this->start().",".$this->page_size;    }    //获取当前文件名    private function php_self() {      return $_SERVER['PHP_SELF'];    }    //上一页    private function pre_page() {      if ($this->page_id() == 1) { //页数等于1        return "<a href=".$this->php_self()."?page_id=1".$this->url().">上一页</a> ";      }elseif ($this->page_id() != 1) { //页数不等于1        return "<a href=".$this->php_self()."?page_id=".($this->page_id()-1).$this->url().">上一页</a> ";      }    }    //显示分页    private function display_page() {      $display_page = "";      if($this->page_num() <= 10){ //小于10页        for ($i=1;$i<=$this->page_num();$i++) //循环显示出页面          $display_page .= "<a href=".$this->php_self()."?page_id=".$i.$this->url().">".$i."</a> ";          return $display_page;      }elseif($this->page_num() > 10){ //大于10页        if($this->page_id() <= 6){          for ($i=1;$i<=10;$i++) //循环显示出页面            $display_page .= "<a href=".$this->php_self()."?page_id=".$i.$this->url().">".$i."</a> ";            return $display_page;        }elseif(($this->page_id() > 6) && ($this->page_num()-$this->page_id() >= 4)){          for ($i=$this->page_id()-5;$i<=$this->page_id()+4;$i++) //循环显示出页面            $display_page .= "<a href=".$this->php_self()."?page_id=".$i.$this->url().">".$i."</a> "; return $display_page;        }elseif(($this->page_id() > 6) && ($this->page_num()-$this->page_id() < 4)){          for ($i=$this->page_num()-9;$i<=$this->page_num();$i++) //循环显示出页面            $display_page .= "<a href=".$this->php_self()."?page_id=".$i.$this->url().">".$i."</a> ";            return $display_page;        }      }    }    //下一页    private function next_page() {      if ($this->page_id() < $this->page_num()) { //页数小于总页数        return "<a href=".$this->php_self()."?page_id=".($this->page_id()+1).$this->url().">下一页</a> ";      }elseif ($this->page_id() == $this->page_num()) { //页数等于总页数        return "<a href=".$this->php_self()."?page_id=".$this->page_num().$this->url().">下一页</a> ";      }    }    // 设置分页信息    public function set_page_info() {      $page_info = "共".$this->datanum."条 ";      $page_info .= "<a href=".$this->php_self()."?page_id=1".$this->url().">首页</a> ";      $page_info .= $this->pre_page();      $page_info .= $this->display_page();      $page_info .= $this->next_page();      $page_info .= "<a href=".$this->php_self()."?page_id=".$this->page_num().$this->url().">尾页</a> ";      $page_info .= "第".$this->page_id()."/".$this->page_num()."页";      return $page_info;    }  }?>