PHP cURL -如何发送请求的正文？

$data = "name=John&age=25";
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$data = array(
    'name' => 'John',
    'age' => 25
);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$data = array(
    'file' => new CURLFile('/path/to/file.jpg')
);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

$ch = curl_init();

// 设置请求URL
curl_setopt($ch, CURLOPT_URL, "https://api.example.com/endpoint");

// 设置请求方法为POST
curl_setopt($ch, CURLOPT_POST, true);

// 设置请求正文数据
$data = "name=John&age=25";
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);

// 执行请求并获取响应
$response = curl_exec($ch);

// 检查是否有错误发生
if(curl_errno($ch)){
    echo 'cURL error: ' . curl_error($ch);
}

// 关闭cURL资源
curl_close($ch);