http访问get链接得到一个xml的结果，而postman访问的get链接得到的是json的结果，怎么保持一致，

方法一.在输出之前，强制定义下输出格式

<?php
namespace api\controllers;

use yii\rest\Controller;
use api\models\Article;
use yii\db\Query;

//自定义资源

class Top3Controller extends Controller
{
    public function actionIndex()
    {
        //  \Yii::$app->response->format = \yii\web\Response::FORMAT_XML;
        \Yii::$app->response->format = \yii\web\Response::FORMAT_JSON;
         $top3 = (new Query())->from('article')->select(['*'])->orderBy('id desc')->limit(3)->all();
        return $top3;
    }
}

?>

方法二

api\config\main.php文件的components中增加对response的配置

'response' => [
    'class' => 'yii\web\Response',
    'on beforeSend' => function ($event) {
        $response = $event->sender;
        $response->format = yii\web\Response::FORMAT_JSON;
    },
],