YII框架学习笔记之命名空间、操作响应与视图操作示例

<?php
/****假设有三个同名的类，输出的值为A，B,C****/
use a\b\c\apple;
use d\e\f\apple as bApple;
use g\h\i\apple;
$app = new apple();//A
$app = new bApple();//B
$app = new \Apple();//C 调用的是全局的

<?php 
namespace app\controllers;
use yii\web\Controller;
use yii\data\Pagination;
use app\models\Country;
class CountryController extends Controller
{
  public function actionIndex()//不叫方法叫操作
  {
    $request = \YII::$app- request;//能够获取到url值
    echo $request- get('id',20);//如果没有传参可以设置默认值
    if($request- isGet) //isPut
    {
      echo "this is get method";
    }
    echo $request- userIP;//获取用户IP
    $res = \YII::$app- response;//获取响应状态
    $res- statusCode = 404;//人为设置响应状态码
    //$res- headers- add('pragma','no-cache');//设置head不设置缓存
    $res- headers- set('pragma','max-age=5');//设置head缓存5分？秒钟
    $res- headers- remove('pragma');
    //跳转
    $res- headers- add("location","http://www.baidu.com");
    $this- redirect("http://www.baidu.com",302);
    //文件下载
    $res- headers- add('content-disposition','attachment;filename="a.jpg"');
    $res- sendFile("robots.txt");
  }
}

<?php
namespace app\controllers;
use yii\web\Controller;
class HelloController extends Controller
{
public function actionIndex()
{
$hellp_str = "hello God!";
$data = array();
$data["view_hello_str"] = $hello_str;
return $this- renderPartial("index",$data);
}
}
? 

$helper_str = "hello world!<script console.log(111);</script "

<?php
use yii\helpers\Html;//转义
use yii\helpers\HtmlPurifier;//过滤html
<h1 <?= Html::encode($view_hello_str);? </h1  <!--Html::encode() 能防止跨站脚本攻击，转义html标签-- 
<h1 <?= HtmlPurifier::process($view_hello_str);? </h1 
<?= $this- render('_overview') ? <!--在一个视图中调用另一个视图-- 

public $layout=false/'layout'

$this- layout=false/'layout'

$this- context- layout=false/'layout'