php+pdo实现的购物车类完整示例

<?php
session_start();
class Cart
{
public $pdo = null;
public function __construct($config)
{
$host = $config['host'];
$user = $config['user'];
$db = $config['db'];
$pwd = $config['pwd'];
if (empty($_SESSION['user_id'])) {
return show(0, '请先登录');
}
try {
$this- pdo = new PDO("mysql:host=$host;dbname=$db", "$user", "$pwd", array(PDO::ATTR_ERRMODE =  PDO::ERRMODE_EXCEPTION));
$this- pdo- query("set names utf8");
} catch (PDOException $e) {
echo $e- getMessage();
}
}
//添加商品到购物车
public function add_cart($productid, $num)
{
$sql = "select price from shop_product where id=?";
$stmt = $this- pdo- prepare($sql);
$stmt- execute(array($productid));
$data = $stmt- fetch(PDO::FETCH_ASSOC);
$price = $data['price'];
$createtime = time();
$sql = "select * from shop_cart where productid=? and userid=?";
$stmt = $this- pdo- prepare($sql);
$stmt- execute(array($productid, $_SESSION['user_id']));
$data = $stmt- fetch(PDO::FETCH_ASSOC);
if ($data) {
$sql = "update shop_cart set num=num+? where userid=? and productid=?";
$params = array($num, $_SESSION['user_id'], $productid);
} else {
$sql = "insert into shop_cart(productid,num,userid,price,createtime) values(?,?,?,?,?)";
$params = array($productid, $num, $_SESSION['user_id'], $price, $createtime);
}
$stmt = $this- pdo- prepare($sql);
$stmt- execute($params);
$rows = $stmt- rowCount();
return $rows ?
show(1, 'ok', $rows) :
show(0, 'fail');
}
//修改购买数量
public function change_num($productid, $num)
{
$sql = "update shop_cart set num=? where userid=? and productid=?";
$stmt = $this- pdo- prepare($sql);
$stmt- execute(array($num, $_SESSION['user_id'], $productid));
$rows = $stmt- rowCount();
return $rows ?
show(1, 'ok', $rows) :
show(0, 'fail');
}
//清空购物车
public function clear_cart()
{
$sql = "delete from shop_cart where userid=?";
$stmt = $this- pdo- prepare($sql);
$this- pdo- execute(array($this- user_id));
$rows = $stmt- rowCount();
return $rows ?
show(1, 'ok', $rows) :
show(0, 'fail');
}
//从购物车中删除商品
public function remove_cart($productid)
{
$sql = "delete from shop_cart where productid=? and userid=?";
$stmt = $this- pdo- prepare($sql);
$stmt- execute(array($productid, $_SESSION['user_id']));
$rows = $stmt- rowCount();
return $rows ?
show(1, 'ok', $rows) :
show(0, 'fail');
}
}
//处理数据
function show($status, $message, $data = array())
{
$result = array(
'status' =  $status,
'message' =  $message,
'data' =  $data
);
exit(json_encode($result));
}
//简单使用
$user = [
'host' =  '',
'user' =  'root',
'pwd' =  'root',
'db' =  'shop',
];
$productid = intval($_POST['productid']);
$num = intval($_POST['num']);
$cart = new Cart($user);
//添加到购物车
$cart- add_cart($productid, $num);
//删除指定的商品
$cart- remove_cart($productid);
//清空
$cart- clear_cart();
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