YII的lazy loading

版本1
require('class\class1.php');
require('class\class1.php');

if($is_girl){
    echo 'this is a girl';
    $class1 = new Class1;
}else{
    echo "this is a boy";
    $class2 = new Class2;
}

版本2
if($is_girl){
    echo 'this is a girl';
    require('class\class1.php');

    $class1 = new Class1;
}else{
    echo "this is a boy";
    require('class\class1.php');
    $class2 = new Class2;
}

版本3
function my_loader($class){
    require('class\class1.php');
    require('class\class1.php');
}
spl_auto_register('my_loader');

if($is_girl){
    echo 'this is a girl';
    $class1 = new Class1;
}else{
    echo "this is a boy";
    $class2 = new Class2;
}

版本4
function my_loader($class){
    require('class\\'.$class.'.php');
}
spl_auto_register('my_loader');

if($is_girl){
    echo 'this is a girl';
    $class1 = new Class1;
}else{
    echo "this is a boy";
    $class2 = new Class2;
}

yii\wendor\yiisoft\yii2\yii.php