PHP如何对接百度自然语言理解接口？

<?php
// 定义接口地址
$url = 'https://aip.baidubce.com/oauth/2.0/token';

// 定义API Key和Secret Key
$apiKey = 'your_api_key';
$secretKey = 'your_secret_key';

// 定义参数数组
$params = array(
    'grant_type' => 'client_credentials',
    'client_id' => $apiKey,
    'client_secret' => $secretKey
);

// 发送POST请求
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);

// 处理返回结果
$result = json_decode($response, true);
if(isset($result['access_token'])){
    $accessToken = $result['access_token'];
    // 调用接口
    $url = 'https://aip.baidubce.com/rpc/2.0/nlp/v1/lexer';
    $params = array(
        'text' => '这是一个测试文本',
        'access_token' => $accessToken
    );
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    $response = curl_exec($ch);
    // 处理返回结果
    $result = json_decode($response, true);
    if(isset($result['items'])){
        foreach($result['items'] as $item){
            echo $item['item'] . ' ';
        }
    }
}
?>