购物车单例模式

  1 <?php
  2 /**
  3  * php 购物车类
  4  * 单例模式
  5 */
  6  class Cart{
  7  static protected $ins; //实例变量
  8  protected $item = array(); //放商品容器
  9 
 10  //禁止外部调用
 11  final protected function __construct(){
 12  }
 13 
 14  //禁止克隆
 15  final protected function __clone(){
 16  }
 17 
 18  //类内部实例化
 19  static protected function Getins(){
 20  if(!(self::$ins instanceof self)){
 21  self::$ins = new self();
 22  }
 23 
 24  return self::$ins;
 25  }
 26 
 27  //为了能使商品跨页面保存，把对象放入session里
 28  public function Getcat(){
 29  if(!($_SESSION['cat']) || !($_SESSION['cat'] instanceof self)){
 30  $_SESSION['cat'] = self::Getins();
 31  }
 32 
 33  return $_SESSION['cat'];
 34  }
 35 
 36  //入列时的检验，是否在$item里存在.
 37  public function Initem($goods_id){
 38  if($this->Gettype() == 0){
 39  return false;
 40  }
 41  if(!(array_key_exists($goods_id,$this->item))){
 42  return false;
 43  }else{
 44  return $this->item[$goods_id]['num']; //返回此商品个数
 45  }
 46  }
 47 
 48  //添加一个商品
 49  public function Additem($goods_id,$name,$num,$price){
 50  if($this->Initem($goods_id) != false){
 51  $this->item[$goods_id]['num'] += $num;
 52  return;
 53  }
 54 
 55  $this->item[$goods_id] = array(); //一个商品为一个数组
 56  $this->item[$goods_id]['num'] = $num; //这一个商品的购买数量
 57  $this->item[$goods_id]['name'] = $name; //商品名字
 58  $this->item[$goods_id]['price'] = $price; //商品单价
 59  }
 60 
 61  //减少一个商品
 62  public function Reduceitem($goods_id,$num){
 63  if($this->Initem($goods_id) == false){
 64  return;
 65  }
 66  if($num > $this->Getunm($goods_id)){
 67  unset($this->item[$goods_id]);
 68  }else{
 69  $this->item[$goods_id]['num'] -=$num;
 70  }
 71  }
 72 
 73  //去掉一个商品
 74  public function Delitem($goods_id){
 75  if($this->Initem($goods_id)){
 76  unset($this->item[$goods_id]);
 77  }
 78  }
 79 
 80  //返回购买商品列表
 81  public function Itemlist(){
 82  return $this->item;
 83  }
 84 
 85  //一共有多少种商品
 86  public function Gettype(){
 87  return count($this->item);
 88  }
 89 
 90  //获得一种商品的总个数
 91  public function Getunm($goods_id){
 92  return $this->item[$goods_id]['num'];
 93  }
 94 
 95  // 查询购物车中有多少个商品
 96  public function Getnumber(){
 97  $num = 0;
 98  if($this->Gettype() == 0){
 99  return 0;
100  }
101 
102  foreach($this->item as $k=>$v){
103  $num += $v['num'];
104  }
105  return $num;
106  }
107 
108  //计算总价格
109  public function Getprice(){
110  $price = 0;
111  if($this->Gettype() == 0){
112  return 0;
113  }
114 
115  foreach($this->item as $k=>$v){
116  $price += $v['num']*$v['num'];
117  }
118  return $price;
119  }
120 
121  //清空购物车
122  public function Emptyitem(){
123  $this->item = array();
124  }
125  }
126 ?>

<?php
session_start();
header("Content-type = text/html; charset=utf-8");
include_once('Cart.php');
$cart = Cart::Getcat();
$cart->Additem('1','php学习教程(脚本学堂版)','5','9999');

$cart->Additem('1','php学习教程(脚本学堂版)','52','9999');
$cart->Additem('2','php学习教程(脚本学堂版)2','52','99992');
print_r($cart);
var_dump($_SESSION['cat']);
?>