php 购物车类的实现代码(单例模式)

3. /**

4. * php 购物车类
5. * 单例模式
6. * Edit bbs.it-home.org
7. */
8. class Cart{
9. static protected $ins; //实例变量
10. protected $item = array(); //放商品容器

11. //禁止外部调用

12. final protected function __construct(){
13. }

14. //禁止克隆

15. final protected function __clone(){
16. }

17. //类内部实例化

18. static protected function Getins(){
19. if(!(self::$ins instanceof self)){
20. self::$ins = new self();
21. }

22. return self::$ins;

23. }

24. //为了能使商品跨页面保存，把对象放入session里

25. public function Getcat(){
26. if(!($_SESSION['cat']) || !($_SESSION['cat'] instanceof self)){
27. $_SESSION['cat'] = self::Getins();
28. }

29. return $_SESSION['cat'];

30. }

31. //入列时的检验，是否在$item里存在.

32. public function Initem($goods_id){
33. if($this->Gettype() == 0){
34. return false;
35. }
36. if(!(array_key_exists($goods_id,$this->item))){
37. return false;
38. }else{
39. return $this->item[$goods_id]['num']; //返回此商品个数
40. }
41. }

42. //添加一个商品

43. public function Additem($goods_id,$name,$num,$price){
44. if($this->Initem($goods_id) != false){
45. $this->item[$goods_id]['num'] += $num;
46. return;
47. }

48. $this->item[$goods_id] = array(); //一个商品为一个数组

49. $this->item[$goods_id]['num'] = $num; //这一个商品的购买数量
50. $this->item[$goods_id]['name'] = $name; //商品名字
51. $this->item[$goods_id]['price'] = $price; //商品单价
52. }

53. //减少一个商品

54. public function Reduceitem($goods_id,$num){
55. if($this->Initem($goods_id) == false){
56. return;
57. }
58. if($num > $this->Getunm($goods_id)){
59. unset($this->item[$goods_id]);
60. }else{
61. $this->item[$goods_id]['num'] -=$num;
62. }
63. }

64. //去掉一个商品

65. public function Delitem($goods_id){
66. if($this->Initem($goods_id)){
67. unset($this->item[$goods_id]);
68. }
69. }

70. //返回购买商品列表

71. public function Itemlist(){
72. return $this->item;
73. }

74. //一共有多少种商品

75. public function Gettype(){
76. return count($this->item);
77. }

78. //获得一种商品的总个数

79. public function Getunm($goods_id){
80. return $this->item[$goods_id]['num'];
81. }

82. // 查询购物车中有多少个商品

83. public function Getnumber(){
84. $num = 0;
85. if($this->Gettype() == 0){
86. return 0;
87. }

88. foreach($this->item as $k=>$v){

89. $num += $v['num'];
90. }
91. return $num;
92. }

93. //计算总价格

94. public function Getprice(){
95. $price = 0;
96. if($this->Gettype() == 0){
97. return 0;
98. }

99. foreach($this->item as $k=>$v){

100. $price += $v['num']*$v['num'];
101. }
102. return $price;
103. }

104. //清空购物车

105. public function Emptyitem(){
106. $this->item = array();
107. }
108. }
109. ?>

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调用示例：

2. include_once('Cart.php');
3. $cart = Cart::Getcat();
4. $cart->Additem('1','php学习教程(程序员之家版)','5','9999');
5. print_r($cart);
6. ?>

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