php pdo自动分页类代码与例子

<?php 
/**
* 类名: PdoPage
* 作者：谢声涛 shishengsoft@gmail.com
* 描述: 继承自PDO类，增加了自动分页功能，类似MS ADO组件的自动分页功能。
*/ www.jb200.com
//-------------开始--------------- 
class PdoPage extends PDO {
public $RecordCount = 0; // 记录集的记录总数 
public $AutoPage = false;// 启用自动分页功能 
public $PageSize = 0;// 每页的记录行数 
public $CurrentPage = 0; // 当前页 
public $Pages = 0;// 总页数 
public $BOF = false; // 游标到记录集之前 
public $EOF = false; // 游标到记录集之后 
private $RecordSet = null;  // 记录集
private $mCurrentRow = -1;  // 记录集中当前游标位置 
private $Rows = 0;//总记录数 
// 关闭连接 
public function Close(){unset($this);}
// 分页查询 
public function QueryEx($SqlString){ 
// 是否启用自动分页功能 
if($this->AutoPage){ 
// 检查PageSize参数 
if ($this->PageSize <=0) die("警告：PageSize不能为负数或零。"); 
// 计算总记录数 
$rs = @parent::query($this->rebuildSqlString($SqlString)); 
$this->Rows = $rs->fetchColumn();
// 计算总页数 
if ($this->Rows < $this->PageSize) {$this->Pages = 1;} 
elseif ($this->Rows % $this->PageSize) {$this->Pages = intval($this->Rows/$this->PageSize)+1;} 
else {$this->Pages = intval($this->Rows/$this->PageSize);} 
// 约束CurrentPage值，使之位于1到Pages之间。 
if($this->CurrentPage < 1) {$this->CurrentPage =1;} 
if($this->CurrentPage > $this->Pages) {$this->CurrentPage = $this->Pages;}
//计算偏移量 
$Offset = $this->PageSize * ($this->CurrentPage - 1); 
// 重组sql语句,SqlString有分号则去掉 
$SqlString = str_replace(";","",$SqlString) . " LIMIT $Offset,$this->PageSize;"; 
} 
// 查询并返回记录集 
$rs = new PDOStatement(); 
$rs = @parent::query($SqlString); 
$this->RecordSet = $rs->fetchAll();//returns an array. 
$this->RecordCount = count($this->RecordSet); 
if(!$this->AutoPage){$this->Pages = (!$this->RecordCount)?0:1;} 
return $this->RecordCount; 
}
// 取得字段值 
public function FieldValue($FieldName=""){ 
return ($this->RecordSet[$this->mCurrentRow][$FieldName]); 
}
//--------移动记录集游标--------------- 
public function Move($RowPos){ 
if ($RowPos<0) $RowPos = 0; 
if ($RowPos > $this->RecordCount-1) $RowPos = $this->RecordCount-1; 
$this->mCurrentRow = $RowPos; 
$this->EOF = false; 
$this->BOF = false;
} 
public function MoveNext(){ 
if($this->mCurrentRow < $this->RecordCount-1){ 
$this->mCurrentRow++; 
$this->EOF = false; 
$this->BOF = false; 
} 
else{ 
$this->EOF = true; 
} 
} 
public function MovePrev(){ 
if($this->mCurrentRow > 0){ 
$this->mCurrentRow--; 
$this->EOF = false; 
$this->BOF = false; 
}else{ 
$this->BOF = true; 
}
} 
public function MoveFirst(){ 
$this->mCurrentRow = 0; 
$this->EOF = false; 
$this->BOF = false; 
}
public function MoveLast(){ 
$this->mCurrentRow = $this->RecordCount-1; 
$this->EOF = false; 
$this->BOF = false; 
} 
//-------------------------------------------------- 
// 用于执行插入、修改、删除等操作 
public function Execute($SqlString){ 
return @parent::query($SqlString); 
} 
//-----------------私有函数----------------------------- 
// 重新构造SQL语句，如将"select * from tb2"改写为"select count(*) from tb2"，旨在提高查询效率。 
private function rebuildSqlString($SqlString){ 
if(preg_match("/select[ ,./w+/*]+ from/",$SqlString,$marr)){
$columns = preg_replace("/select|from/","",$marr[0]);
$columns = preg_replace("//*/","/*",$columns); 
$result = preg_replace("/$columns/"," count(*) ",$SqlString);
return $result; 
} 
}
//-------------结束----------------------------------- 
} 
//-------------结束----------------------------------- 
?> 

<? 
include_once("./pdopage_class.php"); 
$db = new PdoPage("mysql:host=localhost;dbname=mydb","root","123456"); 
$db->Execute("set character set gbk;"); 
$db->AutoPage = false; 
$db->PageSize = 6; 
$db->CurrentPage = 1; 
$db->QueryEx("select * from tb2;"); 
$db->MoveFirst(); 
while (!$db->EOF) { 
echo  $db->FieldValue("id"),"/t",$db->FieldValue("name"),"/t",$db->FieldValue("age"),"/n"; 
$db->MoveNext(); 
} 
$db->Close(); 

?>