<?php
//建立数据库连接
$link = mysql_connect()("localhost", "mysql_user", "mysql_passWord")
or die("Could not connect: " . mysql_error());

// 获取当前页数
if( isset()($_GET['page']) ){
$page = intval( $_GET['page'] );
}
else{
$page = 1;
}

// 每页数量
$PageSize = 10;

// 获取总数据量
$sql = "select count(*) as amount from table";
$result = mysql_query()($sql);
$row = mysql_fetch_row($result);
$amount = $row['amount'];

// 记算总共有多少页
if( $amount ){
if( $amount < $page_size ){ $page_count = 1; } //如果总数据量小于$PageSize，那么只有一页
if( $amount % $page_size ){ //取总数据量除以每页数的余数
$page_count = (int)($amount / $page_size) + 1; //如果有余数，则页数等于总数据量除以每页数的结果取整再加一
}else{
$page_count = $amount / $page_size; //如果没有余数，则页数等于总数据量除以每页数的结果
}
}
else{
$page_count = 0;
}

// 翻页链接
$page_string = '';
if( $page == 1 ){
$page_string .= '第一页|上一页|';
}
else{
$page_string .= '<a href=/blog_article/page/1/gt;第一页/lt;/a/gt;_/lt;a.html href=/blog_article/page/.html'.($page-1).'>上一页</a>|';
}

if( ($page == $page_count) || ($page_count == 0) ){
$page_string .= '下一页|尾页';
}
else{
$page_string .= '<a href=/blog_article/page/.html'.($page+1).'>下一页</a>|<a href=/blog_article/page/.html'.$page_count.'>尾页</a>';
}

// 获取数据，以二维数组格式返回结果
if( $amount ){
$sql = "select * from table order by id desc limit ". ($page-1)*$page_size .", $page_size";
$result = mysql_query($sql);
while ( $row = mysql_fetch_row($result) ){
$rowset[] = $row;
}
}else{
$rowset = array();
}
// 没有包含显示结果的代码，那不在讨论范围，只要用foreach就可以很简单的用得到的二维数组来显示结果
?>

<?php
// FileName: Pager.class.php
// 分页类，这个类仅仅用于处理数据结构，不负责处理显示的工作
Class Pager
{
var $PageSize; //每页的数量
var $CurrentPageID; //当前的页数
var $NextPageID; //下一页
var $PreviousPageID; //上一页
var $numPages; //总页数
var $numItems; //总记录数
var $isFirstPage; //是否第一页
var $isLastPage; //是否最后一页
var $sql; //sql查询语句

function Pager($option)
{
global $db;
$this->_setOptions($option);

// 总条数
if ( !isset($this->numItems) )
{
$res = $db->query($this->sql);
$this->numItems = $res->numRows();
}

// 总页数
if ( $this->numItems > 0 )
{
if ( $this->numItems < $this->PageSize ){ $this->numPages = 1; }
if ( $this->numItems % $this->PageSize )
{
$this->numPages= (int)($this->numItems / $this->PageSize) + 1;
}
else
{
$this->numPages = $this->numItems / $this->PageSize;
}
}
else
{
$this->numPages = 0;
}

switch ( $this->CurrentPageID )
{
case $this->numPages == 1:
$this->isFirstPage = true;
$this->isLastPage = true;
break;

case 1:
$this->isFirstPage = true;
$this->isLastPage = false;
break;

case $this->numPages:
$this->isFirstPage = false;
$this->isLastPage = true;
break;

default:
$this->isFirstPage = false;
$this->isLastPage = false;
}

if ( $this->numPages > 1 )
{
if ( !$this->isLastPage ) { $this->NextPageID = $this->CurrentPageID + 1; }
if ( !$this->isFirstPage ) { $this->PreviousPageID = $this->CurrentPageID - 1; }
}
return true;
}

/***
*
* 返回结果集的数据库连接
* 在结果集比较大的时候可以直接使用这个方法获得数据库连接，然后在类之外遍历，这样开销较小
* 如果结果集不是很大，可以直接使用getPageData的方式获取二维数组格式的结果
* getPageData方法也是调用本方法来获取结果的
*
***/
function getDataLink()
{
if ( $this->numItems )
{
global $db;
$PageID = $this->CurrentPageID;
$from = ($PageID - 1)*$this->PageSize;
$count = $this->PageSize;
$link = $db->limitQuery($this->sql, $from, $count); //使用Pear DB::limitQuery方法保证数据库兼容性
return $link;
}
else
{
return false;
}
}

/***
*
* 以二维数组的格式返回结果集
*
***/
function getPageData()
{
if ( $this->numItems )
{
if ( $res = $this->getDataLink() )
{
if ( $res->numRows() )
{
while ( $row = $res->fetchRow() )
{
$result[] = $row;
}
}
else
{
$result = array();
}
return $result;
}
else
{
return false;
}
}
else
{
return false;
}
}

function _setOptions($option)
{
$allow_options = array(
'PageSize',
'CurrentPageID',
'sql',
'numItems'
);

foreach ( $option as $key => $value )
{
if ( in_array($key, $allow_options) && ($value != null) )
{
$this->$key = $value;
}
}
return true;
}
}
?>

<?php
// FileName: test_pager.php
// 这是一段简单的示例代码，前边省略了使用pear db类建立数据库连接的代码
require "Pager.class.php";

if ( isset($_GET['page']) )
{
$page = (int)$_GET['page'];
}
else
{
$page = 1;
}

$sql = "select * from table order by id";
$pager_option = array(
"sql" => $sql,
"PageSize" => 10,
"CurrentPageID" => $page
);

if ( isset($_GET['numItems']) )
{
$pager_option['numItems'] = (int)$_GET['numItems'];
}

$pager = @new Pager($pager_option);
$data = $pager->getPageData();

if ( $pager->isFirstPage )
{
$turnover = "首页|上一页|";
}
else
{
$turnover = "<a href='/blog_article/page/1/amp;numItems/.html".$pager->numItems."'>首页</a>|<a href='/blog_article/page/.html".$pager->PreviousPageID."&numItems=".$pager->numItems."'>上一页</a>|";
}

if ( $pager->isLastPage )
{
$turnover .= "下一页|尾页";
}
else
{
$turnover .="<a href='/blog_article/page/.html".$pager->NextPageID."&numItems=".$pager->numItems."'>下一页</a>|<a href='/blog_article/page/.html".$pager->numPages."&numItems=".$pager->numItems."'>尾页</a>";
}
?>

<?php
class MemberPager extends Pager
{
function showMemberList()
{
global $db;
$data = $this->getPageData();
// 显示结果的代码
// ......
}
}

/// 调用
if ( isset($_GET['page']) )
{
$page = (int)$_GET['page'];
}
else
{
$page = 1;
}

$sql = "select * from members order by id";
$pager_option = array(
"sql" => $sql,
"PageSize" => 10,
"CurrentPageID" => $page
);

if ( isset($_GET['numItems']) )
{
$pager_option['numItems'] = (int)$_GET['numItems'];
}
$pager = @new MemberPager($pager_option);
$pager->showMemberList();
?>

<?php
function validate_email($email){
$exp="^[a-z'0-9]+([._-][a-z'0-9]+)*@([a-z0-9]+([._-][a-z0-9]+))+$";
if(eregi($exp,$email)){ //先用正则表达式验证email格式的有效性
if(checkdnsrr(array_pop(explode()("@",$email)),"MX")){//再用checkdnsrr验证email的域名部分的有效性
   return true;
}else{
   return false;
}
}else{
   return false;
}
}

//注意：checkdnsrr函数在win主机上是无效的!下面是国外某程序员提出的一种解决办法，另外写了个函数代替checkdnsrr函数：
function myCheckDNSRR($hostName, $recType=''){
if(!emptyempty($hostName)){
if( $recType=='' ) $recType="MX";
    exec("nslookup -type=$recType $hostName", $result);
foreach($result as $line){
if(eregi("^$hostName",$line)){
return true;
}
}
return false;
}
return false;
}