php SESSION类(购物车类)

/**
* 文件描述 Session类
* =================================================================
* 文件名称 session.class.php
* -----------------------------------------------------------------
* 适用环境： PHP5.2.x / mysql 5.0.x
* -----------------------------------------------------------------
* 作 者 04ie。com
* -----------------------------------------------------------------
* 创建时间 2010-2-1
* =================================================================
*/
class Session
{
/**
* session默认有效时间
* @access public
* @var ineger $_expiry
*/
public $_expiry = 3600;
/**
* 有效域名
* @access public
* @var string $_domain
*/
public $_domain = '.phpfamily.cn';
//初始化
public function __construct()
{
ini_set('session.use_trans_id', 0);
ini_set('session.gc_maxlifetime', $this->_expiry);
ini_set('session.use_cookie', 1);
ini_set('session.cookie_path', '//m.sbmmt.com/m/');
ini_set('session.cookie_domain', $this->_domain);
session_module_name('user');
session_set_save_handler(
array(&$this, 'open'),
array(&$this, 'close'),
array(&$this, 'read'),
array(&$this, 'write'),
array(&$this, 'destroy'),
array(&$this, 'gc')
);
session_start();
}
/**
* 打开session
* @access public
* @param string $savePath
* @param string $sName
* @return true
*/
public function open($savePath, $sName)
{
$this->_conn = mysql_connect('localhost', 'root', '');
mysql_select_db('databases');
mysql_query('SET NAMES "utf8"');
return true;
}
/**
* 关闭session
* @access public
* @return bool
*/
public function close()
{
return mysql_close($this->_conn);
}
/**
* 读取session
* @access public
* @param string $sid sessionID
* @return mixed
*/
public function read($sid)
{
$sql = "SELECT data FROM sessions WHERE sessionid='%s'";
$sql = sprintf($sql, $sid);
$res = mysql_query($sql, $this->_conn);
$row = mysql_fetch_assoc($res);
return !$row ? null : $row['data'];
}
/**
* 写入session
* @access public
* @param string $sid sessionID
* @param string $data serialize序列化后的session内容
* @return
*/
public function write($sid, $data)
{
$expiry = time() + $this->_expiry;
$sql = "REPLACE INTO sessions (sessionid,expiratio
n,data) VALUES ('%s', '%d', '%s')";
$sql = sprintf($sql, $sid, $expiry, $data);
mysql_query($sql, $this->_conn);
return true;
}
/**
* 销毁session
* @access public
* @param string $sid sessionID
* @return
*/
public function destroy($sid)
{
$sql = "DELETE FROM sessions WHERE sessionid='%s'";
$sql = sprintf($sql, $sid);
mysql_query($sql, $this->_conn);
return true;
}
/**
* 清理过期session
* @access public
* @param integer $time
* @return
*/
public function gc($time = 0)
{
$sql = "DELETE FROM sessions WHERE expiration < '%d'";
$sql = sprintf($sql, time());
mysql_query($sql, $this->_conn);
mysql_query('OPTIMIZE TABLE sessions');
return true;
}

class Cart{
public function Cart() {
if(!isset($_SESSION['cart'])){
$_SESSION['cart'] = array();
}
}

/*
添加商品
param int $id 商品主键
string $name 商品名称
float $price 商品价格
int $num 购物数量
*/
public function addItem($id,$name,$price,$num,$img) {
//如果该商品已存在则直接加其数量
if (isset($_SESSION['cart'][$id])) {
$this->incNum($id,$num);
return;
}
$item = array();
$item['id'] = $id;
$item['name'] = $name;
$item['price'] = $price;
$item['num'] = $num;
$item['img'] = $img;
$_SESSION['cart'][$id] = $item;
}

/*
修改购物车中的商品数量
int $id 商品主键
int $num 某商品修改后的数量，即直接把某商品
的数量改为$num
*/
public function modNum($id,$num=1) {
if (!isset($_SESSION['cart'][$id])) {
return false;
}
$_SESSION['cart'][$id]['num'] = $num;
}

/*
商品数量+1
*/
public function incNum($id,$num=1) {
if (isset($_SESSION['cart'][$id])) {
$_SESSION['cart'][$id]['num'] += $num;
}
}

/*
商品数量-1
*/
public function decNum($id,$num=1) {
if (isset($_SESSION['cart'][$id])) {
$_SESSION['cart'][$id]['num'] -= $num;
}

//如果减少后，数量为0，则把这个商品删掉
if ($_SESSION['cart'][$id]['num'] <1) {
$this->delItem($id);
}
}

/*
删除商品
*/
public function delItem($id) {
unset($_SESSION['cart'][$id]);
}

/*
获取单个商品
*/
public function getItem($id) {
return $_SESSION['cart'][$id];
}

/*
查询购物车中商品的种类
*/
public function getCnt() {
return count($_SESSION['cart']);
}

/*
查询购物车中商品的个数
*/
public function getNum(){
if ($this->getCnt() == 0) {
//种数为0，个数也为0
return 0;
}

$sum = 0;
$data = $_SESSION['cart'];
foreach ($data as $item) {
$sum += $item['num'];
}
return $sum;
}

/*
购物车中商品的总金额
*/
public function getPrice() {
//数量为0，价钱为0
if ($this->getCnt() == 0) {
return 0;
}
$price = 0.00;
foreach ($this->items as $item) {
$price += $item['num'] * $item['price'];
}
return sprintf("%01.2f", $price);
}

/*
清空购物车
*/
public function clear() {
$_SESSION['cart'] = array();
}
}