为什么 PHP 没有捕获“找不到类"?错误? [英] Why doesn't PHP catch a "Class not found" error?

问题描述

在以下示例中，如果该类不存在，我想捕获错误并创建一个 Null 类.

In the following example, if the class does not exist, I want to catch the error and create a Null class instead.

但尽管我有 try/catch 语句，PHP 只是告诉我 Class 'SmartFormasdfasdf' not found.

But in spite of my try/catch statements, PHP simply tells me Class 'SmartFormasdfasdf' not found.

如何让 PHP 捕获找不到类"错误?

<?php
class SmartFormLogin extends SmartForm {
    public function render() {
        echo '<p>this is the login form</p>';
    }
}

class SmartFormCodeWrapper extends SmartForm {
    public function render() {
        echo '<p>this is the code wrapper form</p>';
    }
}

class SmartFormNull extends SmartForm {
    public function render() {
        echo '<p>the form "' . htmlentities($this->idCode) . '" does not exist</p>';
    }
}

class SmartForm {

    protected $idCode;

    public function __construct($idCode) {
        $this->idCode = $idCode;
    }

    public static function create($smartFormIdCode) {
        $className = 'SmartForm' . $smartFormIdCode;
        try {
            return new $className($smartFormIdCode);
        } catch (Exception $ex) {
            return new SmartFormNull($smartformIdCode);
        }
    }
}

$formLogin = SmartForm::create('Login');
$formLogin->render();
$formLogin = SmartForm::create('CodeWrapper');
$formLogin->render();
$formLogin = SmartForm::create('asdfasdf');
$formLogin->render();
?>

解决方案:

谢谢@Mchl，我当时就是这样解决的:

Solution:

Thanks @Mchl, this is how I solved it then:

public static function create($smartFormIdCode) {
  $className = 'SmartForm' . $smartFormIdCode;
  if(class_exists($className)) {
    return new $className($smartFormIdCode);
  } else {
    return new SmartFormNull($smartFormIdCode);
  }
} 

推荐答案

因为这是一个致命错误.使用 class_exists() 函数检查类是否存在.

Because it's a fatal error. Use class_exists() function to check if class exist.

另外:PHP 不是 Java - 除非您重新定义默认错误处理程序，否则它将引发错误而不是抛出异常.

Also: PHP is not Java - unless you redefined default error handler, it will raise errors and not throw exceptions.

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