{ "error_code": 282133, "error_msg": "param text not exist"}怎么处理

header('Content-Type:application/json');
$text = "happy";
	// 调用情感倾向分析
	$client->sentimentClassify($text);
	$token = $b;//将获取的access_token值放进去
	// echo $token;
	$url = 'https://aip.baidubce.com/rpc/2.0/nlp/v1/sentiment_classify?access_token='. $token;
	// echo $url;
	$text = json_encode($text);
	$res = request_post($url , $text);//调用请求函数
	echo $res;  //将识别的数据输出到前端