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', '/');
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();
 }
}