用thinkphp操作session

<?php
namespace Home\Controller;
use Think\Controller;

class Demo1Controller extends Controller {
    public function index(){
        $user = M("city")->select();
         
        $this->assign(‘list‘,$user);
         
        $this->display();
    }
    
    //session赋值
    public function test1() {
        session(‘username‘,‘admin‘);
        session(‘useralias‘,‘管理员‘);
        
        echo ‘session赋值‘;
    }
    
    //session取值
    public function test2() {
        echo ‘session取值<br />‘;
        echo ‘username：‘.session(‘username‘).‘<br/>‘;
        echo ‘useralias：‘.session(‘useralias‘).‘<br/>‘;
    }
    
    //删除session
    public function test3() {
        session(‘username‘,null);
        session(‘useralias‘,null);
    
        echo ‘删除session‘;
    }
    
    //判断session是否存在
    public function test4() {
        if(session(‘?username‘)) {
            echo ‘username存在<br/>‘;
        } else {
            echo ‘username不存在<br/>‘;
        }
        
        if(session(‘?useralias‘)) {
            echo ‘useralias存在‘;
        } else {
            echo ‘useralias不存在‘;
        }
    }
}