YII behaviors使用

<?php
/**
* Created by PhpStorm.
* Date: 2016/5/27
* Time: 14:16
*/
namespace frontend\libs;
use Yii;
use yii\base\Action;
use yii\base\ActionFilter;

class FilterTest extends ActionFilter{

//在action之前运行，可用来过滤输入
public function beforeAction($action) {
echo '在调用action前显示<br/>';
return TRUE;//如果返回值为false,则action不会运行
}

//在action之后运行，可用来过滤输出
public function afterAction($action, $result) {
return $result.'在调用action后显示<br/>';//可以对action输出的$result进行过滤，retun的内容会直接显示
}
}

<?php
/**
* Created by PhpStorm.
* Date: 2016/5/27
* Time: 14:19
*/
namespace frontend\controllers;

use yii\web\controller;

class TestbehaviorController extends Controller{

public function behaviors(){
return [
'test'=>[
'class'=>'frontend\libs\FilterTest',//调用过滤器
],
];
}
public function actionFilter(){
return "当前action显示<br/>";//返回的内容会递交给过滤器，由afterAction处理
}
}