面向对象——sleep()、wakeup()和异常类

1、sleep(), wakeuup()实例

代码示例

<?php
    abstract class User{
        protected $name = '李明';
        private $age = 30;
    }
    class Infor extends User{
        public $sex = '男';
        private $isStudent = false;
        protected static $nationality = '中国/CHINA';
        public function __get($name)
        {
            return $this->$name;
        }
        public function __sleep(): array
        {
            return ['name', 'sex', 'isStudent'];
        }
        public function __wakeup()
        {
            $this->age = 35;
            $this->sex = '保密';
        }
    }
    $infor = new Infor();
    echo "序列化--" . serialize($infor);
    echo "<hr>";
    $in = serialize($infor);
    echo "反序列化--" ;
    var_dump(unserialize($in));
?>

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2、自定义异常类, 处理用户登录与验证

• __toString() 方法用于一个类被当成字符串时应怎样回应

代码示例

<?php
class MyException extends Exception
{
    public function __construct($message,$code){
        $this->code = $code;
        $this->message = $message;
    }
   //重写异常信息输出格式
    public function __toString()
    {
        return '登录失败！['.$this->code.']:'.$this->message;
    }
}
try{
    $username = $_POSt['username'];
    $password = $_POST['password'];
    if($username !='zcx123'){
        throw new MyException('用户名不存在',1);
    }elseif($password !='zcx123456'){
        throw new MyException('密码错误',2);
    }
}catch(MyException $e){
    echo $e;
}
?>

---

3、匿名函数

代码示例

<?php
interface iDb 
{
    public function __construct(...$params);
}
$res = (new class ('mysql:host=localhost;dbname=forum', 'root', 'root') implements iDb {
        private $db = null;
        public function __construct(...$params)
        {
            $this->db = new PDO($params[0],$params[1],$params[2]);
        }
        public function select($where="")
        {
            $where = empty($where) ? '' : ' WHERE ' . $where;
            return $this->db
            ->query('SELECT uId,uName FROM tb1_user ' . $where . ' LIMIT 4')
            ->fetchAll(PDO::FETCH_ASSOC);
        }
    }
)->select();
printf('<pre>%s</pre>', print_r($res, true));

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学习总结

本节课我们学习了sleep()、wakeup()、异常类和匿名函数。通过反复看视频和参考其他同学的作业对异常类知识基本了解，还需要后期的实战来强化。