微信小程序wx.request使用POST请求时后端无法获取数据解决办法

header: { "Content-Type": "application/x-www-form-urlencoded" },

wx.request({ 
 url: 'https://后端网址/user/updatePhone.html',
 method: 'POST',
 data: { phone: _phone, openid: _openid},
 header: { "Content-Type": "application/x-www-form-urlencoded" },
 success: res => {
 console.log(res.data);
 }
});

<?php
namespace app\car\controller;
use think\Controller;
use think\Db;
use think\Request;
 
class User extends Base
{
	public function _initialize(){		
		parent::_initialize();
	} 
 
 public function updatePhone(){
 if(!isset($_POST['phone'])||!isset($_POST['openid'])){
  header("Content-type: text/html; charset=utf-8"); 
  echo '参数错误'.$_POST['phone'];
  exit;
 }	
		$openid= trim($_POST['openid']);
		try{
			$updata['tel'] = trim($_POST['phone']);
			Db::name('user')->where('wxopenid',$openid)->update($updata);
			$code=1;
			$msg="修改成功";
		} catch (\Exception $e) {
			$code=0;
			$msg="修改失败";
		}
		return $this->outputMsg($code,$msg);
 }
}