第一步：获取access_token:

<?php$clientId = '';     // 替换为你的 PayPal Client ID
$clientSecret = ''; // 替换为你的 PayPal Client Secret// PayPal API 请求的 URL
$url = "https://api-m.sandbox.paypal.com/v1/oauth2/token";// 初始化 cURL
$ch = curl_init();// 设置 cURL 请求的参数
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_USERPWD, $clientId . ":" . $clientSecret);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/x-www-form-urlencoded'));
curl_setopt($ch, CURLOPT_POSTFIELDS, "grant_type=client_credentials");// 执行请求
$response = curl_exec($ch);// 检查请求是否出错
if (curl_errno($ch)) {echo 'Error:' . curl_error($ch);
} else {// 打印响应结果echo $response;
}// 关闭 cURL
curl_close($ch);

第二步：创建订单：

<?php$accessToken = ''; // 替换为你的访问令牌
$paypalRequestId = '7b92603e-77ed-4896-8e78-5dea2050476a'; // 替换为你的 PayPal 请求 ID// API URL
$url = "https://api-m.sandbox.paypal.com/v2/checkout/orders";// 创建订单的数据
$data = ["intent" => "CAPTURE","purchase_units" => [["reference_id" => "d9f80740-38f0-11e8-b467-0ed5f89f718b","amount" => ["currency_code" => "USD","value" => "1.00"]]],"payment_source" => ["paypal" => ["experience_context" => ["return_url" => "https://example.com/returnUrl","cancel_url" => "https://example.com/cancelUrl"]]]
];// 初始化 cURL
$ch = curl_init();// 设置 cURL 参数
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json','PayPal-Request-Id: ' . $paypalRequestId,'Authorization: Bearer ' . $accessToken,
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));// 执行请求并获取响应
$response = curl_exec($ch);// 检查是否有错误
if (curl_errno($ch)) {echo 'Error:' . curl_error($ch);
} else {// 输出响应echo $response;
}// 关闭 cURL
curl_close($ch);