php银联支付接口demo

<?php
// 银联支付配置信息
$merId = '商户号';
$merKey = '商户密钥';
$orderId = '订单号';
$amount = '订单金额';
$notifyUrl = '回调地址';

// 构建支付请求参数
$params = [
    'merId' => $merId,
    'orderId' => $orderId,
    'amount' => $amount,
    'notifyUrl' => $notifyUrl,
];

// 签名
$sign = sign($params, $merKey);

// 构建支付请求URL
$url = 'https://pay.unionpay.com/api/preauth';
$params['sign'] = $sign;
$queryString = http_build_query($params);

// 跳转到支付页面
header("Location: $url?$queryString");

/**
 * 签名函数
 * @param array $params 请求参数
 * @param string $merKey 商户密钥
 * @return string 签名结果
 */
function sign($params, $merKey) {
    ksort($params);
    $str = '';
    foreach ($params as $key => $value) {
        $str .= "&$key=$value";
    }
    $str = substr($str, 1) . '&key=' . $merKey;
    return md5($str);
}
?>