对于instanceof的多态开关（考虑继承）：

switch(true) {  
    case $objectToTest instanceof TreeRequest:
        echo "tree request";
        break;
    case $objectToTest instanceof GroundRequest:
        echo "ground request";
        break;
}

对于类名应完全匹配的开关：

$class = get_class($objectToTest);

switch($class) {  
    case 'TreeRequest':
        echo "tree request";
        break;
    case 'GroundRequest':
        echo "ground request";
        break;
}

以下是比较正确的：

$class = get_class($objectToTest);

switch($class) {  
    case TreeRequest::class:
        echo "tree request";
        break;
    case GroundRequest::class:
        echo "ground request";
        break;
}

这样就可以正确地比较名称空间（您不必键入它们），如果名称空间或类名等任何内容发生更改，您将收到一个体面的IDE错误，通知您代码已损坏。

使用match表达式，结果如下所示：

return match(get_class($object)) {  
   TreeRequest::class => "tree request",
   GroundRequest::class => "ground request",
   default => "default request"
}

记住它忽略了继承并且只接受当前类。考虑继承的匹配表达式：

return match(true) {  
   $object instanceof TreeRequest=> "tree request",
   $object instanceof GroundRequest => "ground request",
   default => "default request"
}